Random overheating and then cools down. HELP :(
01-29-2015, 12:32 PM
#27
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
I read on another thread that the fans stay on after shutting the car when the coolant temperature is over 230F. Isn't that way too high? So every single time that happened to me, I was inches away from blowing my engine?
Has it ever happened to you guys?
Can a radiator cap that's not holding the correct pressure cause a car to overheat?
01-29-2015, 12:51 PM
#28
Driving my unreliable rx8
Well 230 is not true I've gotten fans on when i stop multiple times and the temps were not too high. Some times for minutes and sometimes for seconds.
I don't know what you mean by testing them but you might be able to.
A bad cap can cause fluid to boil
And give you hot spots which can be very bad.
I don't know what you mean by testing them but you might be able to.
A bad cap can cause fluid to boil
And give you hot spots which can be very bad.
01-29-2015, 03:08 PM
#30
Both fans run at the same speed. There is a relay stepper process that switches them from in series (low) to parallel (high). The low mod triggers the series mode.
If you have a situation where only one fan is on, the one that is off is bad. If one is on, it will just blow hot air back through the other side and in front of the radiator. I have a post someplace that walks through this, I believe, or at least a pointer to the appropriate schematic. I will look for it.
This post has the drawing. https://www.rx8club.com/series-i-tro...8/#post4252471
If you have a situation where only one fan is on, the one that is off is bad. If one is on, it will just blow hot air back through the other side and in front of the radiator. I have a post someplace that walks through this, I believe, or at least a pointer to the appropriate schematic. I will look for it.
This post has the drawing. https://www.rx8club.com/series-i-tro...8/#post4252471
01-30-2015, 03:08 AM
#31
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
Well 230 is not true I've gotten fans on when i stop multiple times and the temps were not too high. Some times for minutes and sometimes for seconds.
I don't know what you mean by testing them but you might be able to.
A bad cap can cause fluid to boil
And give you hot spots which can be very bad.
I don't know what you mean by testing them but you might be able to.
A bad cap can cause fluid to boil
And give you hot spots which can be very bad.
Both fans run at the same speed. There is a relay stepper process that switches them from in series (low) to parallel (high). The low mod triggers the series mode.
If you have a situation where only one fan is on, the one that is off is bad. If one is on, it will just blow hot air back through the other side and in front of the radiator. I have a post someplace that walks through this, I believe, or at least a pointer to the appropriate schematic. I will look for it.
This post has the drawing. https://www.rx8club.com/series-i-tro...8/#post4252471
If you have a situation where only one fan is on, the one that is off is bad. If one is on, it will just blow hot air back through the other side and in front of the radiator. I have a post someplace that walks through this, I believe, or at least a pointer to the appropriate schematic. I will look for it.
This post has the drawing. https://www.rx8club.com/series-i-tro...8/#post4252471
Does Fan 2 (left side of the car) sound noticeably louder than Fan 1? My Fan 1 (or fans, I don't know if both come on at the same time) stay on before reaching 208F, even with the AC off. Why is that? When I do turn on the AC, Fan 2 kicks in and cools the car down. It's so loud haha.
Also, I've been looking at some fan diagrams. What does "refrigerant pressure switch" mean?
01-30-2015, 10:04 AM
#32
Driving my unreliable rx8
My ambient is from 35-110. Most summers are upper 90- low 100's. In Louisiana ambient was in the 90's all summer and my fans stayed on a lot more.
Refrigerant switch is for the AC
Refrigerant switch is for the AC
01-30-2015, 10:46 AM
#33
on high, they are loud. if one is not loud, tis broken
if one is burned, and shorted, the other will always be on high, and will come on. at the low point. if it is open, same thing, but it will not come on until the high point
Posted From RX8Club.com Android App
if one is burned, and shorted, the other will always be on high, and will come on. at the low point. if it is open, same thing, but it will not come on until the high point
Posted From RX8Club.com Android App
01-30-2015, 10:46 AM
#34
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
Weird thing is, when I shut my car off at 222F, the fans did not stay on. But when I turned the key to ON, the fans turned on.I'm still wondering why it randomly climbs to 220-sh. Every other time it'd max out at 215F in slow moving traffic, and then drop down to 207F while idling.
01-30-2015, 10:53 AM
#35
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
What's open? :/
For some odd reason, the fan on the right side of the car (Fan 1) isn't as loud as the fan on the left side (Fan 2). Also, the fans stay on on low (not loud lol) before the fan on temp (208F), even with the AC off.
01-31-2015, 02:05 AM
#38
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
--UPDATE--
Today I took the car out this afternoon in 88F weather and left it idling for a few minutes. After about 30 minutes in, it slowly creeped up to 210F and dropped back down to 208F.
I had to move to another place 200m in front so I floored it to get up to 35mph. Temp shot up to 215F and slowly dropped down as I came to a stop. Again, while idling, temp went up to 215F, I knew something was wrong coz it never used to go this high when idling (I'm talking before this whole overheat issue started last month), so I turned the heater on full and watched it slowly drop to 206F. Turning the AC back on, it would slowly creep up to 215F. I had to turn on the heater again to drop it down. All this while idling.
THIS IS STARTING TO LOOK LIKE A FAN ISSUE
To confirm that, I took the car on about a 2 mile empty road, while getting there, the temp was around 210-212F. Temp seemed to level out while moving. So I got to the road and floored it to get up to around 70mph. Temp shot up to 215F again, and as I put it back into 5th, slowly went down to 206F. Turned around and came back down the same road, floored it to get to 50mph, temp went up to 213F and as I was cruising down at around 40mph, temps went down to around 210F. (I remember a few months back, temp would drop down to around 190F cruising down the same road, maybe going a little faster.)
Got off that road and kept shifting around 4000rpm until I got home, temp peaked at 213F, went back down to 208F when I dropped the revs.
So it seems like driving it hard and keeping the speed up keeps the car cooler. Granny shifting at 1500rpm and going slow heats the car.
Maybe it's coz the water pump is moving more water?
So in conclusion, radiator issue or fan issue?
Today I took the car out this afternoon in 88F weather and left it idling for a few minutes. After about 30 minutes in, it slowly creeped up to 210F and dropped back down to 208F.
I had to move to another place 200m in front so I floored it to get up to 35mph. Temp shot up to 215F and slowly dropped down as I came to a stop. Again, while idling, temp went up to 215F, I knew something was wrong coz it never used to go this high when idling (I'm talking before this whole overheat issue started last month), so I turned the heater on full and watched it slowly drop to 206F. Turning the AC back on, it would slowly creep up to 215F. I had to turn on the heater again to drop it down. All this while idling.
THIS IS STARTING TO LOOK LIKE A FAN ISSUE
To confirm that, I took the car on about a 2 mile empty road, while getting there, the temp was around 210-212F. Temp seemed to level out while moving. So I got to the road and floored it to get up to around 70mph. Temp shot up to 215F again, and as I put it back into 5th, slowly went down to 206F. Turned around and came back down the same road, floored it to get to 50mph, temp went up to 213F and as I was cruising down at around 40mph, temps went down to around 210F. (I remember a few months back, temp would drop down to around 190F cruising down the same road, maybe going a little faster.)
Got off that road and kept shifting around 4000rpm until I got home, temp peaked at 213F, went back down to 208F when I dropped the revs.
So it seems like driving it hard and keeping the speed up keeps the car cooler. Granny shifting at 1500rpm and going slow heats the car.
Maybe it's coz the water pump is moving more water?
So in conclusion, radiator issue or fan issue?
Last edited by Aston177; 01-31-2015 at 02:13 AM.
01-31-2015, 09:20 AM
#39
Driving my unreliable rx8
Pull your radiator, bring it to a shop, to be rodded and vatted. If that doesn't work then take a good look at fans.
What are you using to monitor temps? Where ate you located?
What are you using to monitor temps? Where ate you located?
01-31-2015, 11:09 AM
#40
if it were me, I would put foam around radiator, easy and cheap. thus makes sure the outside air goes through the radiator.
if that does not work, make sure nothing went through the grill and is blocking air flow.
test at 50 mph to take the fans out of the equation. the air through the grill at 50 is way more than the fans can push
I assume the tray in front of radiator is installed
if it is still over 200, at 50, on a level road, I would look for a thermostat or radiator problem. I pull a trailer, up hill, at 70, and only hit 185, factory thermostat, foam.
if that does not work, make sure nothing went through the grill and is blocking air flow.
test at 50 mph to take the fans out of the equation. the air through the grill at 50 is way more than the fans can push
I assume the tray in front of radiator is installed
if it is still over 200, at 50, on a level road, I would look for a thermostat or radiator problem. I pull a trailer, up hill, at 70, and only hit 185, factory thermostat, foam.
The following users liked this post:
Kamal El (10-19-2018)
01-31-2015, 01:15 PM
#41
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
What's rodded and vatted btw?From my android tablet running Torque. Sri Lanka haha. Pretty hot over here.
if it were me, I would put foam around radiator, easy and cheap. thus makes sure the outside air goes through the radiator.
if that does not work, make sure nothing went through the grill and is blocking air flow.
test at 50 mph to take the fans out of the equation. the air through the grill at 50 is way more than the fans can push
I assume the tray in front of radiator is installed
if it is still over 200, at 50, on a level road, I would look for a thermostat or radiator problem. I pull a trailer, up hill, at 70, and only hit 185, factory thermostat, foam.
if that does not work, make sure nothing went through the grill and is blocking air flow.
test at 50 mph to take the fans out of the equation. the air through the grill at 50 is way more than the fans can push
I assume the tray in front of radiator is installed
if it is still over 200, at 50, on a level road, I would look for a thermostat or radiator problem. I pull a trailer, up hill, at 70, and only hit 185, factory thermostat, foam.
I peeped in. Nothing went though the front grill.
Yes, the tray is in place.
Gotcha! I'll do that first thing I wake up. What temp should I see and how fast should it drop to that temp? It's around 80-92F here.
01-31-2015, 01:57 PM
#42
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
--3RD UPDATE--
Car only runs hot when idling under the sun in hot weather.
Took the car again this evening, got it up to 213F when sprinting followed by a slow crawl. Dropped back down to 203F while idling with the AC on. It did not run hot throughout the journey. Same ambient temp as before when it ran hot.
So lost right now
Car only runs hot when idling under the sun in hot weather.
Took the car again this evening, got it up to 213F when sprinting followed by a slow crawl. Dropped back down to 203F while idling with the AC on. It did not run hot throughout the journey. Same ambient temp as before when it ran hot.
So lost right now
01-31-2015, 06:54 PM
#43
this is what the foam is for.
sitting still, fans suck hot air through radiator. it cannot get out of engine bay easy, so it sneaks around the radiator, and gets sucked back through. the hot air does not cool the car well
at speed, enough cool air is blasted through the grill to overcome the problem.
foam..
sitting still, fans suck hot air through radiator. it cannot get out of engine bay easy, so it sneaks around the radiator, and gets sucked back through. the hot air does not cool the car well
at speed, enough cool air is blasted through the grill to overcome the problem.
foam..
02-01-2015, 02:40 PM
#44
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
this is what the foam is for.
sitting still, fans suck hot air through radiator. it cannot get out of engine bay easy, so it sneaks around the radiator, and gets sucked back through. the hot air does not cool the car well
at speed, enough cool air is blasted through the grill to overcome the problem.
foam..
sitting still, fans suck hot air through radiator. it cannot get out of engine bay easy, so it sneaks around the radiator, and gets sucked back through. the hot air does not cool the car well
at speed, enough cool air is blasted through the grill to overcome the problem.
foam..
I did the highway test you mentioned.
81F ambient temp. The highway was around 1km long so I couldn't keep doing it for long. Entered the highway at 50mph, temp was 208F. It slowly dropped to 203F, and then as I was slowing down coming towards the exit, dropped to 199F. It did not go lower than that, but maybe it would have, if I stayed on the highway for longer.
After getting off the highway, I tried my best to maintain 50mph. Temp stayed around 203F.
Flooring it would get it up to 215F.
02-01-2015, 05:03 PM
#45
Finally, a keyboard...
If all the water is hot, it will take a bit to cool it down. But, from what you described, I would go with the foam and the fan on low mod. I am back to my factory tune chasing a different problem (means factory fan on points) and I freaked out when the temp when to 203 (usually runs 185). I immediately switched on the fans, and the temp started going down about a degree a minute all the way to 185. If all you had was a KM, and dropped it that far, (sounds like a degree every 15 seconds or so) I think you have an airflow problem. I could just be that the factory foam finally gave up. There may still be a different issue, but you need to get this one fixed no matter what. I strongly suggest the fans on low mod as well. I ground the wire on mine to the bolt right in front of the fuse box. I is configured that way right now.
If all the water is hot, it will take a bit to cool it down. But, from what you described, I would go with the foam and the fan on low mod. I am back to my factory tune chasing a different problem (means factory fan on points) and I freaked out when the temp when to 203 (usually runs 185). I immediately switched on the fans, and the temp started going down about a degree a minute all the way to 185. If all you had was a KM, and dropped it that far, (sounds like a degree every 15 seconds or so) I think you have an airflow problem. I could just be that the factory foam finally gave up. There may still be a different issue, but you need to get this one fixed no matter what. I strongly suggest the fans on low mod as well. I ground the wire on mine to the bolt right in front of the fuse box. I is configured that way right now.
02-02-2015, 06:45 AM
#46
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
Finally, a keyboard... If all the water is hot, it will take a bit to cool it down. But, from what you described, I would go with the foam and the fan on low mod. I am back to my factory tune chasing a different problem (means factory fan on points) and I freaked out when the temp when to 203 (usually runs 185). I immediately switched on the fans, and the temp started going down about a degree a minute all the way to 185. If all you had was a KM, and dropped it that far, (sounds like a degree every 15 seconds or so) I think you have an airflow problem. I could just be that the factory foam finally gave up. There may still be a different issue, but you need to get this one fixed no matter what. I strongly suggest the fans on low mod as well. I ground the wire on mine to the bolt right in front of the fuse box. I is configured that way right now.
Yes, it's most probably a foam issue. I took the car to the service station to get it washed and I told them to wash the radiator as well. They sprayed a chemical to loosen up the dirt and then blasted it with a water gun. As they were doing that, the foam at the bottom of the radiator was moving and exposing the engine side due to the air pressure of the water gun. It was loose. I'm sure it lets a lot of air out while moving. Also, they were pretty brittle. I poked it with a screwdriver and it made a dent haha.
Sadly, it seems like I did more harm than good. Blasting it with water bent the radiator fins
Here is a pic of my radiator right now.
I feel like a complete idiot now. Think this will increase my temps even more?
02-02-2015, 06:53 AM
#47
You gonna eat that?
iTrader: (1)
But doesn't running the AC on force the fans to go on high? Since I'm in a hot climate and I have the AC on 24/7, isn't it kind of pointless?
Yes, it's most probably a foam issue. I took the car to the service station to get it washed and I told them to wash the radiator as well. They sprayed a chemical to loosen up the dirt and then blasted it with a water gun. As they were doing that, the foam at the bottom of the radiator was moving and exposing the engine side due to the air pressure of the water gun. It was loose. I'm sure it lets a lot of air out while moving. Also, they were pretty brittle. I poked it with a screwdriver and it made a dent haha.
Sadly, it seems like I did more harm than good. Blasting it with water bent the radiator fins
Here is a pic of my radiator right now.
I feel like a complete idiot now. Think this will increase my temps even more?
Yes, it's most probably a foam issue. I took the car to the service station to get it washed and I told them to wash the radiator as well. They sprayed a chemical to loosen up the dirt and then blasted it with a water gun. As they were doing that, the foam at the bottom of the radiator was moving and exposing the engine side due to the air pressure of the water gun. It was loose. I'm sure it lets a lot of air out while moving. Also, they were pretty brittle. I poked it with a screwdriver and it made a dent haha.
Sadly, it seems like I did more harm than good. Blasting it with water bent the radiator fins
Here is a pic of my radiator right now.
I feel like a complete idiot now. Think this will increase my temps even more?
02-02-2015, 11:49 AM
#48
Good news is that those are your condensor fins, not radiator...
Here is the deal with the foam.. With the car sitting still, and the fans on, the air behind the bumper and in front of the radiator gets pulled through the radiator, and into the engine compartment. It gets hot on the way. The path out of the engine compartment is not simple. The fans blow it up, there is no outlet that direction, so you get a layer of hot air, filling the engine bay, with more being blow in by the fans. That air can get out by going out the wheel wells, or out the bottom OR, by going back around the radiator to when the fans are drawing from. singe the fans are drawing from that side, this is a really easy route. Now, instead of 100 degree outside air going through the radiator, you have 100 degree air mixed with some 200 degree air. If the AC is on, it further heats the air, and the radiator cannot dump heat to the high temp air all that well.
At speed, there is enough air getting crammed through the grill to generate pressure and keep the air from going around the radiator, and your temps drop because the radiator is seeing cooler air.
If the fans are on high, and you are not moving much, it makes it worse. AC on is even worse. If the nose were not on the car, it is not as bad.
My event was getting stuck in traffic, with the AC on, and I noticed somethign was wrong when the ac quit working, the temp gauge was way over to the right. It was like 95 degrees out.
My fix is in the congrats thread. Basically, fans on low and foam. When I finished this, I could sit in a hot parking lot, with the AC on max, and not see 200 degrees, all day long and be freezing in the car. My daughter was late geting out of something, so I know I am good like this for 20 minutes.
You may well need a radiator. But, if this is the problem, all the radiator in the world will not solve it, unless the new one comes with something to seal the front from the back.
Here is the deal with the foam.. With the car sitting still, and the fans on, the air behind the bumper and in front of the radiator gets pulled through the radiator, and into the engine compartment. It gets hot on the way. The path out of the engine compartment is not simple. The fans blow it up, there is no outlet that direction, so you get a layer of hot air, filling the engine bay, with more being blow in by the fans. That air can get out by going out the wheel wells, or out the bottom OR, by going back around the radiator to when the fans are drawing from. singe the fans are drawing from that side, this is a really easy route. Now, instead of 100 degree outside air going through the radiator, you have 100 degree air mixed with some 200 degree air. If the AC is on, it further heats the air, and the radiator cannot dump heat to the high temp air all that well.
At speed, there is enough air getting crammed through the grill to generate pressure and keep the air from going around the radiator, and your temps drop because the radiator is seeing cooler air.
If the fans are on high, and you are not moving much, it makes it worse. AC on is even worse. If the nose were not on the car, it is not as bad.
My event was getting stuck in traffic, with the AC on, and I noticed somethign was wrong when the ac quit working, the temp gauge was way over to the right. It was like 95 degrees out.
My fix is in the congrats thread. Basically, fans on low and foam. When I finished this, I could sit in a hot parking lot, with the AC on max, and not see 200 degrees, all day long and be freezing in the car. My daughter was late geting out of something, so I know I am good like this for 20 minutes.
You may well need a radiator. But, if this is the problem, all the radiator in the world will not solve it, unless the new one comes with something to seal the front from the back.
02-04-2015, 01:54 PM
#50
Registered
Thread Starter
Join Date: Jun 2013
Posts: 321
Likes: 0
Received 0 Likes
on
0 Posts
First of all, I am extremely sorry for the late reply. Ive been caught up with work and still couldn't take out the bumper and seal around the radiator
Thank you so much for the detailed explanation. Yes, I totally get it now. It's definitely the foam around the radiator. The foam on my car is moving freely so it's not sealing properly.
So, you stopped a full on overheat from sealing around the radiator? WOW. I'm definitely doing those 2 mods now lol.
I don't think the bent fins caused an issue. Temps are still the same. I drove around a lot yesterday and the temp dropped when idling :/ It really seems like it only overheats when it's sunny. Never when it's not. Temps climb to around 213F when flooring. At one point, I kept the revs up in30mph traffic and it went up to 217F :/ I'll have to wait till Monday to seal around the radiator
Yeah I'm planning on doing that once I remove the bumper to seal around the radiator. Bents fins aren't affecting temps though
Thanks for the replies guys. Really appreciate it. Since there is no serious problem with my car, I'm gonna keep driving it until Monday. I'll let you guys know how the temps are after sealing around
Good news is that those are your condensor fins, not radiator...
Here is the deal with the foam.. With the car sitting still, and the fans on, the air behind the bumper and in front of the radiator gets pulled through the radiator, and into the engine compartment. It gets hot on the way. The path out of the engine compartment is not simple. The fans blow it up, there is no outlet that direction, so you get a layer of hot air, filling the engine bay, with more being blow in by the fans. That air can get out by going out the wheel wells, or out the bottom OR, by going back around the radiator to when the fans are drawing from. singe the fans are drawing from that side, this is a really easy route. Now, instead of 100 degree outside air going through the radiator, you have 100 degree air mixed with some 200 degree air. If the AC is on, it further heats the air, and the radiator cannot dump heat to the high temp air all that well.
At speed, there is enough air getting crammed through the grill to generate pressure and keep the air from going around the radiator, and your temps drop because the radiator is seeing cooler air.
If the fans are on high, and you are not moving much, it makes it worse. AC on is even worse. If the nose were not on the car, it is not as bad.
My event was getting stuck in traffic, with the AC on, and I noticed somethign was wrong when the ac quit working, the temp gauge was way over to the right. It was like 95 degrees out.
My fix is in the congrats thread. Basically, fans on low and foam. When I finished this, I could sit in a hot parking lot, with the AC on max, and not see 200 degrees, all day long and be freezing in the car. My daughter was late geting out of something, so I know I am good like this for 20 minutes.
You may well need a radiator. But, if this is the problem, all the radiator in the world will not solve it, unless the new one comes with something to seal the front from the back.
Here is the deal with the foam.. With the car sitting still, and the fans on, the air behind the bumper and in front of the radiator gets pulled through the radiator, and into the engine compartment. It gets hot on the way. The path out of the engine compartment is not simple. The fans blow it up, there is no outlet that direction, so you get a layer of hot air, filling the engine bay, with more being blow in by the fans. That air can get out by going out the wheel wells, or out the bottom OR, by going back around the radiator to when the fans are drawing from. singe the fans are drawing from that side, this is a really easy route. Now, instead of 100 degree outside air going through the radiator, you have 100 degree air mixed with some 200 degree air. If the AC is on, it further heats the air, and the radiator cannot dump heat to the high temp air all that well.
At speed, there is enough air getting crammed through the grill to generate pressure and keep the air from going around the radiator, and your temps drop because the radiator is seeing cooler air.
If the fans are on high, and you are not moving much, it makes it worse. AC on is even worse. If the nose were not on the car, it is not as bad.
My event was getting stuck in traffic, with the AC on, and I noticed somethign was wrong when the ac quit working, the temp gauge was way over to the right. It was like 95 degrees out.
My fix is in the congrats thread. Basically, fans on low and foam. When I finished this, I could sit in a hot parking lot, with the AC on max, and not see 200 degrees, all day long and be freezing in the car. My daughter was late geting out of something, so I know I am good like this for 20 minutes.
You may well need a radiator. But, if this is the problem, all the radiator in the world will not solve it, unless the new one comes with something to seal the front from the back.
Thank you so much for the detailed explanation. Yes, I totally get it now. It's definitely the foam around the radiator. The foam on my car is moving freely so it's not sealing properly.
So, you stopped a full on overheat from sealing around the radiator? WOW. I'm definitely doing those 2 mods now lol.
I don't think the bent fins caused an issue. Temps are still the same. I drove around a lot yesterday and the temp dropped when idling :/ It really seems like it only overheats when it's sunny. Never when it's not. Temps climb to around 213F when flooring. At one point, I kept the revs up in30mph traffic and it went up to 217F :/ I'll have to wait till Monday to seal around the radiator
Thanks for the replies guys. Really appreciate it. Since there is no serious problem with my car, I'm gonna keep driving it until Monday. I'll let you guys know how the temps are after sealing around