Rx8 operating temps (coolant temps)
03-24-2015, 09:08 AM
#53
Registered
Join Date: Jan 2015
Posts: 232
Likes: 0
Received 0 Likes
on
0 Posts
220*f is kinda hot in my opinion.
My 04 would turn the fans on @ 212*f, then turn off at 202*f.
I installed a fan kit that turns them on @ 190*f and back off at 181*f. I haven't seen my coolant temps go above 195*f since.
I'm pretty sure the thermostat opens at 180*f cause that's what temp I sit at while cruising on a open road.
Please note the kit I use is not popular here due to the fact that the man who makes it apparently scammed a bunch of members here under a different company name. My own personal experience dealing with him was good though... Buyer beware.
My 04 would turn the fans on @ 212*f, then turn off at 202*f.
I installed a fan kit that turns them on @ 190*f and back off at 181*f. I haven't seen my coolant temps go above 195*f since.
I'm pretty sure the thermostat opens at 180*f cause that's what temp I sit at while cruising on a open road.
Please note the kit I use is not popular here due to the fact that the man who makes it apparently scammed a bunch of members here under a different company name. My own personal experience dealing with him was good though... Buyer beware.
03-24-2015, 09:15 AM
#54
Registered
Join Date: Jan 2015
Posts: 232
Likes: 0
Received 0 Likes
on
0 Posts
Let me know how that goes if you don't mind.
When I bought this kit I didn't do much research on it and it turns out "MindsEyeEngineering" is really a guy named Scott that owned another company that ripped off some forum members here. When I delt with them I had no problems though.
When I bought this kit I didn't do much research on it and it turns out "MindsEyeEngineering" is really a guy named Scott that owned another company that ripped off some forum members here. When I delt with them I had no problems though.
07-01-2016, 06:51 PM
#55
Recently out of curiosity I started to track my temperature. For my 04 RX8, it is normally at 228 F. It fluctuates to 234F and then back to 228F. Now that I read this post, I'm starting to worry that my car is heating too much. It still feel fine, well I honestly wouldn't know how it'd feel with temperature under 200F. My engine coolant reservoir is bad, and I have plenty of coolant in there. What else should I check or change out?
07-01-2016, 07:42 PM
#56
It should be running between 180F and 200F unless it's really really hot outside (hotter than it gets in MO).
Is your surge tank not holding pressure? How do you know it's bad?
A good start would be to flush the coolant system, then go on with replacing things like pressure cap and the thermostat.
Is your surge tank not holding pressure? How do you know it's bad?
A good start would be to flush the coolant system, then go on with replacing things like pressure cap and the thermostat.
07-02-2016, 12:43 AM
#57
Sicker than your average
Join Date: Nov 2012
Location: Colombo, Sri Lanka
Posts: 1,015
Likes: 0
Received 14 Likes
on
13 Posts
Originally Posted by Enrique2014
Recently out of curiosity I started to track my temperature. For my 04 RX8, it is normally at 228 F. It fluctuates to 234F and then back to 228F. Now that I read this post, I'm starting to worry that my car is heating too much. It still feel fine, well I honestly wouldn't know how it'd feel with temperature under 200F. My engine coolant reservoir is bad, and I have plenty of coolant in there. What else should I check or change out?
07-02-2016, 08:08 AM
#58
Registered
Join Date: Jan 2015
Posts: 232
Likes: 0
Received 0 Likes
on
0 Posts
If you have a hairline crack right below your radiator cap, then this can contribute to high temps. I drove around 105 to 110F ambient temperatures with AC on and never go beyond 205 F. My setup is only stock rad and fan control kit. Add more water than coolant and check your fan speed.
07-02-2016, 11:52 AM
#59
Sicker than your average
Join Date: Nov 2012
Location: Colombo, Sri Lanka
Posts: 1,015
Likes: 0
Received 14 Likes
on
13 Posts
No cracks in my case. Car is pretty much new. Fans are new. Coolant radio is 30:70. My car will stay below 200F while moving at speed. It's only when I'm idling. HEAT SOAK is the issue here 
If I'm stuck in traffic for over 40 mins, the coolant temp will slowly creep to 220F. Turning off the AC will bring it back down to 206F (that's when the fans go into low speed).
It was 102F today and my car was mostly around 215F. A little better than I expected but still kinda high.
I'm having a hard time believing that your STOCK cooling system NEVER goes over 205F in 110F weather
If I'm stuck in traffic for over 40 mins, the coolant temp will slowly creep to 220F. Turning off the AC will bring it back down to 206F (that's when the fans go into low speed). It was 102F today and my car was mostly around 215F. A little better than I expected but still kinda high.
I'm having a hard time believing that your STOCK cooling system NEVER goes over 205F in 110F weather
Last edited by Nisaja; 07-02-2016 at 11:58 AM.
07-02-2016, 01:51 PM
#60
The only way to get around heat soak is to stop things from getting hot. Vent your engine bay, relocate your battery, get rid of that airbox, triple your coolant capacity, even just setting your fans to come on at lower temperatures (or wire high speed to a manual switch) would help.
There are plenty of solutions because it's a very small problem, and now that we've identified it fix it.
07-02-2016, 03:11 PM
#62
usually during the summer in Missouri, the temperature stays between 80's to low 90's. I only started looking at coolant temp after I noticed my temperature gauge rise a little. You know how the needle is usually two or three ticks below the halfway mark? Well when I was out driving, I noticed mine two or three ticks past the halfway mark. I got a little freaked out, so I just let of the gas and put it in 5th gear since I was in 4th. I just kept an eye on the gauge and it dropped back to the usual 2 or 3 ticks below the half way mark. Yesterday I took the car out again and the same thing happened. It goes fro 2 to 3 below the halfway mark, to 2 to 3 above the half way mark, it kept doing this on and off while i drove for a good 15-20 minutes. I kept an eye on my coolant temperature and watched it go from 228F to 234F and then back down to 228. Which brought me to my question, has my car always done this or have I never noticed? To me the car feels normal when I drive, its not sluggish.
07-02-2016, 03:14 PM
#63
My 8 has original radiator and original coolant reservoir. I already flushed the coolant about a year ago and added new coolant. I bought a new coolant reservoir, I just haven't gotten around to replacing it yet since I've heard its a PITA. I should probably check and replace the radiator too, as I've noticed that it has a few pebbles imbedded in it, whenever I'm under the car.
07-03-2016, 12:34 AM
#64
Sicker than your average
Join Date: Nov 2012
Location: Colombo, Sri Lanka
Posts: 1,015
Likes: 0
Received 14 Likes
on
13 Posts
Originally Posted by Legot
It's because of the humidity. Water in the air takes out more heat, faster, than dry air.
The only way to get around heat soak is to stop things from getting hot. Vent your engine bay, relocate your battery, get rid of that airbox, triple your coolant capacity, even just setting your fans to come on at lower temperatures (or wire high speed to a manual switch) would help.
There are plenty of solutions because it's a very small problem, and now that we've identified it fix it.
The only way to get around heat soak is to stop things from getting hot. Vent your engine bay, relocate your battery, get rid of that airbox, triple your coolant capacity, even just setting your fans to come on at lower temperatures (or wire high speed to a manual switch) would help.
There are plenty of solutions because it's a very small problem, and now that we've identified it fix it.
I don't think turning on the fans manually would help because when i'm idling with the AC on, the fans are already on full speed. This only happens when i'm idling. When I'm traveling at speed, the car stays at around 195F. It's only when I'm sitting in one place for over 30 mins the coolant starts to climb. It doesn't jump to 220F. It gradually increases over like a 20 min period. Specially when stuck in traffic, with the road and surrounding cars heat. Traffic over here can get pretty insane! Complete gridlock for 1 hour is not uncommon. That's when this car suffers 
weirdly, it was 102F yesterday and the car idled in traffic at 208F. Sometimes even when it's 95F outside, the coolant would hit 220F at idle. Pretty inconsistent. And this happens to ALL the RX-8s here. Yes, ALL. A friend of mine has a 2010 R3, bone stock, 12k miles on the clock, and he basically runs the whole time with the heater on to keep the temps below 210F.
The struggle is real
Originally Posted by 9krpmrx8
Mine was just sitting in traffic with the AC on for over 20 minutes, never went above 195F. It's 96F with 41% Humidity right now.
Idling for 20 mins at 195F is a dream come true to me.
Last edited by Nisaja; 07-03-2016 at 12:36 AM.
07-03-2016, 01:36 AM
#65
Maybe you could get an auxiliary radiator? They're fun and effective! You'd just need a fan and somewhere to put it, I'd recommend stacking it with the passenger side oil cooler and running it in series post heater core.
Good point about the fans, i didn't think about that. You could still just cut holes in your hood, as long as you make them look pretty they'll look pretty.
Good point about the fans, i didn't think about that. You could still just cut holes in your hood, as long as you make them look pretty they'll look pretty.
07-03-2016, 03:07 AM
#66
Registered
Join Date: Jan 2015
Posts: 232
Likes: 0
Received 0 Likes
on
0 Posts
No cracks in my case. Car is pretty much new. Fans are new. Coolant radio is 30:70. My car will stay below 200F while moving at speed. It's only when I'm idling. HEAT SOAK is the issue here If I'm stuck in traffic for over 40 mins, the coolant temp will slowly creep to 220F. Turning off the AC will bring it back down to 206F (that's when the fans go into low speed).
It was 102F today and my car was mostly around 215F. A little better than I expected but still kinda high.
I'm having a hard time believing that your STOCK cooling system NEVER goes over 205F in 110F weather
If I'm stuck in traffic for over 40 mins, the coolant temp will slowly creep to 220F. Turning off the AC will bring it back down to 206F (that's when the fans go into low speed). It was 102F today and my car was mostly around 215F. A little better than I expected but still kinda high.
I'm having a hard time believing that your STOCK cooling system NEVER goes over 205F in 110F weather
Its all stock but fan control kit turns the fan on at full speed around 188F. its Humid outside and fans keep running on high speed and thats why it never go above 205 F even in 105 to 110F ambient. Currently me and my mechanic guy is thinking of a solution to rapidly decrease coolant temps if its gets above 200F by implementing something new. It will be fun, will post results in few days and will explain all about it
Last edited by RX8 pearl red; 07-03-2016 at 03:10 AM.
07-05-2016, 01:18 AM
#67
Sicker than your average
Join Date: Nov 2012
Location: Colombo, Sri Lanka
Posts: 1,015
Likes: 0
Received 14 Likes
on
13 Posts
Originally Posted by RX8 pearl red
Its all stock but fan control kit turns the fan on at full speed around 188F. its Humid outside and fans keep running on high speed and thats why it never go above 205 F even in 105 to 110F ambient. Currently me and my mechanic guy is thinking of a solution to rapidly decrease coolant temps if its gets above 200F by implementing something new. It will be fun, will post results in few days and will explain all about it
How long have you been stuck in traffic? I'm sure it has to go above 205F with a stock cooling system.
Doesn't matter how low the trigger temp of the fans are, if the fans aren't spinning fast enough to maintain that temp, the temp will rise. That's my problem.
07-05-2016, 05:14 AM
#68
Registered
Join Date: Jan 2015
Posts: 232
Likes: 0
Received 0 Likes
on
0 Posts
Because I run the AC the fans are on full speed, so my car stays below 205F too, but only up to 20 mins. After that heat soak is inevitable
How long have you been stuck in traffic? I'm sure it has to go above 205F with a stock cooling system.
Doesn't matter how low the trigger temp of the fans are, if the fans aren't spinning fast enough to maintain that temp, the temp will rise. That's my problem.
How long have you been stuck in traffic? I'm sure it has to go above 205F with a stock cooling system.
Doesn't matter how low the trigger temp of the fans are, if the fans aren't spinning fast enough to maintain that temp, the temp will rise. That's my problem.
Well, We don't have traffic jams here for like hours, I've been stuck in traffic for 15 to 20 minutes in summer heat couple of times. Strange thing is that on Idle with AC on, temps don't climb. it stays between 197F to 202F. temps only climb when i rev up with AC on and rise up to 205F and as soon as i let go of the throttle, temps come down to 197F in 2 or 3 minutes. Please understand that all this reading in with the AC on. Without AC, i never see above 195 F whether i am in traffic, doing high revving or idling or driving in summer heat.
I occasional clean my AC grill alongwith my rad. sealed all sides of the rad. and just use my fan control kit. that all about it
Thread
Thread Starter
Forum
Replies
Last Post
Nisaja
New Member Forum
2
08-06-2015 01:27 AM
