over heating
05-09-2015, 05:44 AM
#1
New Member
Thread Starter
Join Date: May 2015
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
over heating
I am new to this forum. My name is Kelly I have a 2004 Mazda RX8 with 78,000 miles. I bought it in October 2015 I am the second owner. It started over heating Thursday while i was picking my kids up from school. I have been reading the treads here and thought that someone on here could help figure out what was wrong. No warning lights came on the dash, the fan didn't even kick on, but my coolant bottle was low. I sat at the school till the engine cooled and put water in the bottle. I drove it home and it has been parked ever since.
Last edited by kelly2004RX8; 05-09-2015 at 05:57 AM.
05-09-2015, 07:47 AM
#2
Well, it's very hard to say exactly what it could be...
The good news is, it "could be" relatively cheap and easy to fix:
- could be a bad thermostat
- or a water pump
- or you could a slow leak in the bottle or a hose somewhere and when the coolant level get low enough it over heats. (The sensor in the bottle is a known issue)
The bad news:
- It could be the radiator. The plastic on the radiator commonly (read always) after time becomes brittle and cracks, and there is a small connector that commonly breaks off.
The ugly:
The rotary engine is very sensitive to overheating.
That said if you caught it quick enough you may be ok, however the common theme is if you see the Temperature gauge move you're already screwed.
I'm just guessing here but this doesn't sound like it's going to be cheap.
You're going to have to have a mechanic look at it.
I would also recommend getting a compression test.
Good luck and keep us updated please
edit: Or the low speed rad fan is burnt out
The good news is, it "could be" relatively cheap and easy to fix:
- could be a bad thermostat
- or a water pump
- or you could a slow leak in the bottle or a hose somewhere and when the coolant level get low enough it over heats. (The sensor in the bottle is a known issue)
The bad news:
- It could be the radiator. The plastic on the radiator commonly (read always) after time becomes brittle and cracks, and there is a small connector that commonly breaks off.
The ugly:
The rotary engine is very sensitive to overheating.
That said if you caught it quick enough you may be ok, however the common theme is if you see the Temperature gauge move you're already screwed.
I'm just guessing here but this doesn't sound like it's going to be cheap.
You're going to have to have a mechanic look at it.
I would also recommend getting a compression test.
Good luck and keep us updated please
edit: Or the low speed rad fan is burnt out
Last edited by wcs; 05-09-2015 at 08:33 AM.
05-09-2015, 02:29 PM
#3
Welcome.
A few questions. How did you know it overheated? Was it just spitting water? That will give us a place to start thinking. For me, the first time mine got hot is scared me. I did most of the things in the Congrats thread below, then wrote the thread to share. Making sure the fans work and making sure the air flows the right way are 2 big things.
A few questions. How did you know it overheated? Was it just spitting water? That will give us a place to start thinking. For me, the first time mine got hot is scared me. I did most of the things in the Congrats thread below, then wrote the thread to share. Making sure the fans work and making sure the air flows the right way are 2 big things.
05-09-2015, 11:21 PM
#5
Thanks,
Smoke or Steam? If the pressure cap releases you will see the steam, you may see the needle go up at the same time. A lot of folks will tell you that the world ends if the temp gauge moves. You did the right thing shutting down as soon as you saw something wrong. Mine almost pegged the gauge. I did not notice until the AC cut off because it was so hot. My bad. You likely did better than I did. I put another 60,000 miles on my car since then, with a lot of track time. There are a few things to check. I am assuming some familiarity with the mechanics of the car, about the same level as my kids and/or wife. If these steps bother you, get some help.
I highly recommend getting something that will tell you the car is running hot. Some like the ODBII connector with a smart phone and app. Personally, I want something always on and in the car. 3 of our 4 cars have an ultragauge. They are about $60. You buy them directly from their website. I think they give you a rebate if you prove you followed the installation instructions. If you can borrow something that will read the ODBII data, that is great. It should be able to tell you temp. If you post your location, there may be a local member that can help.
First, fill it back up with water and see if it starts. If you get a lot of steam out of of the exhaust, or it will not start, things could be bad. This is the first test. Do not tighten the filler cap past the first little click. You do not want to pressurize the cooling system. You just want to keep it from burping out coolant.
Second, you can test the fans. After the car starts, let it run a minute, then turn on the AC. The fans on the radiator should come on. You should be able to hear them. They only run when the compressor runs, but it will run for a few minutes when you first start the car. I recommend having the hood up. If they do not come on, you have likely found a culprit. The same is true if only one comes on. First check the fuses for the fans, then check the relays. There are a few threads here about troubleshooting the fans.
Third, if they do come on, it is time to check the thermostat. This is best done with something that can tell you engine temp. Without that, you risk overheating again as well as getting a burn from hot coolant. If you do not have the device, you can continue, just be VERY careful. There is hot water and a risk of burns. Turn off the AC. Very carefully remove the radiator cap (remember, it is not all the way attached, so there is no pressure in the system). Make sure there is water still in the tank. Add some if it has gone down. You should be able to see it. Watch it closely. After several minutes, you should see it start to move around. It may go up and down, it may swirl. This is the thermostat opening. If this happens, you have a thermostat that works, a water pump that that works, and if the fans came on you have all the necessary pieces of a cooling system.
This is where it is really nice to have the gauge that reads temp. If you have one, tighten the radiator cap all the way. Then watch the temp. You should see it rise to about 185, sit there for a few minutes, then start to rise again. The pause is when the thermostat opens, it starts to rise again after all the cold water in the radiator has entered the engine. It will rise until the fans come on around 210 degrees or so. Then the fans should kick on, and the temp will go down a bit.
If all of this works out, check out the cooling related mods in the Congrats thread below. Specifically the fans on low mod and the foam around the radiator mod. Both helped me a great deal.
Smoke or Steam? If the pressure cap releases you will see the steam, you may see the needle go up at the same time. A lot of folks will tell you that the world ends if the temp gauge moves. You did the right thing shutting down as soon as you saw something wrong. Mine almost pegged the gauge. I did not notice until the AC cut off because it was so hot. My bad. You likely did better than I did. I put another 60,000 miles on my car since then, with a lot of track time. There are a few things to check. I am assuming some familiarity with the mechanics of the car, about the same level as my kids and/or wife. If these steps bother you, get some help.
I highly recommend getting something that will tell you the car is running hot. Some like the ODBII connector with a smart phone and app. Personally, I want something always on and in the car. 3 of our 4 cars have an ultragauge. They are about $60. You buy them directly from their website. I think they give you a rebate if you prove you followed the installation instructions. If you can borrow something that will read the ODBII data, that is great. It should be able to tell you temp. If you post your location, there may be a local member that can help.
First, fill it back up with water and see if it starts. If you get a lot of steam out of of the exhaust, or it will not start, things could be bad. This is the first test. Do not tighten the filler cap past the first little click. You do not want to pressurize the cooling system. You just want to keep it from burping out coolant.
Second, you can test the fans. After the car starts, let it run a minute, then turn on the AC. The fans on the radiator should come on. You should be able to hear them. They only run when the compressor runs, but it will run for a few minutes when you first start the car. I recommend having the hood up. If they do not come on, you have likely found a culprit. The same is true if only one comes on. First check the fuses for the fans, then check the relays. There are a few threads here about troubleshooting the fans.
Third, if they do come on, it is time to check the thermostat. This is best done with something that can tell you engine temp. Without that, you risk overheating again as well as getting a burn from hot coolant. If you do not have the device, you can continue, just be VERY careful. There is hot water and a risk of burns. Turn off the AC. Very carefully remove the radiator cap (remember, it is not all the way attached, so there is no pressure in the system). Make sure there is water still in the tank. Add some if it has gone down. You should be able to see it. Watch it closely. After several minutes, you should see it start to move around. It may go up and down, it may swirl. This is the thermostat opening. If this happens, you have a thermostat that works, a water pump that that works, and if the fans came on you have all the necessary pieces of a cooling system.
This is where it is really nice to have the gauge that reads temp. If you have one, tighten the radiator cap all the way. Then watch the temp. You should see it rise to about 185, sit there for a few minutes, then start to rise again. The pause is when the thermostat opens, it starts to rise again after all the cold water in the radiator has entered the engine. It will rise until the fans come on around 210 degrees or so. Then the fans should kick on, and the temp will go down a bit.
If all of this works out, check out the cooling related mods in the Congrats thread below. Specifically the fans on low mod and the foam around the radiator mod. Both helped me a great deal.
05-20-2015, 02:42 PM
#11
Registered
Join Date: Apr 2015
Location: Denver, CO
Posts: 80
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for posting this thread about the overheating. It got me to do a thorough check on my coolant tank last night and found that it appears to be low. I did read up that the little floater is common to just sink in the tank and not register properly so people tend to unplug their sensor so as to not see the light on.
I did not know this before about the sensor and when looking at my tank out of curiosity I noticed there was the top plug zip tied to the plug going to the unit with the "H" on top and then the other plug was dangling and covered in grime. I googled the site and found that this is the coolant sensor plug and that people like to unplug is because their coolant light always comes on due to a sunk floater. Turns out my coolant was a tad low and since I had no coolant I put some water in there (hope thats ok!) I tell you trying to read the coolant tank was pretty damn hard to do, I couldnt tell where the level was at. but found that someone posted it needs to be filled to the lowest level on the vertical open slot on the left side (as there are 2 vertical slots). I am hoping this is correct and anyone tell me otherwise if I filled it incorrectly that way.
Now I am debating the ultragauge which 04Green posted up. I wouldn't mind getting one if it tells all the things I saw on the website about temps and mpg. If anyone else uses that I imagine it will tell me the coolant/water temp hopefully so I can just set it to whatever is the dangerous temp and set the alarm to go off if it gets there so I can shut the car off quickly. It looks like that temp from other threads is 210-215 correct?
I did not know this before about the sensor and when looking at my tank out of curiosity I noticed there was the top plug zip tied to the plug going to the unit with the "H" on top and then the other plug was dangling and covered in grime. I googled the site and found that this is the coolant sensor plug and that people like to unplug is because their coolant light always comes on due to a sunk floater. Turns out my coolant was a tad low and since I had no coolant I put some water in there (hope thats ok!) I tell you trying to read the coolant tank was pretty damn hard to do, I couldnt tell where the level was at. but found that someone posted it needs to be filled to the lowest level on the vertical open slot on the left side (as there are 2 vertical slots). I am hoping this is correct and anyone tell me otherwise if I filled it incorrectly that way.
Now I am debating the ultragauge which 04Green posted up. I wouldn't mind getting one if it tells all the things I saw on the website about temps and mpg. If anyone else uses that I imagine it will tell me the coolant/water temp hopefully so I can just set it to whatever is the dangerous temp and set the alarm to go off if it gets there so I can shut the car off quickly. It looks like that temp from other threads is 210-215 correct?
Thread
Thread Starter
Forum
Replies
Last Post
05rx8mazda
RX-8 Parts For Sale/Wanted
18
11-28-2015 09:42 AM
Learners_Permit
Series I Interior, Audio, and Electronics
8
09-27-2015 07:38 PM