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Running hot...where do I start

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Old 07-31-2011, 09:43 PM
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Running hot...where do I start

I did a search but could not find a topic discussing what I am experiencing. I have an 04 GT Auto with about 120K on it. I just bought the car last November so I am unsure of everything that has/hasn't been done to it besides all the mods I have done to it. Here is my issue:

I have a ScangaugeII on the car so I could monitor the read outs from the car in a "true" reading instead of relying on our dummy gauges. I had noticed when I ran the Texas 8 in April that my car kept wanting to overheat. After speaking with some awesome guys down in Texas while I was there, we came to the conclusion that since I was an auto and I was paddle shifting the whole run through the mountain, my tranny was getting hot which in return was overheating the engine. I spoke to another guy on the run, who was having the same issue before, and he told me he installed a tranny cooler and it worked and help. So, I did the same and by monitoring the scangaugeII before the install of the tranny cooler and then after, I noticed between a 15-30 degree drop in tranny temp depending on the day. While this is awesome, I am still noticing that on a day with the weather between 95-108 degrees, my car will run consistently between 205-230 degrees. It even when I am on the highway, it will not run lower than 205 degrees. When I am stopped at a light or at a drive-thru for food, the car will start getting up around the 230 degree mark. Speaking with Jimmy, Renesis on the boards, we both agree its an issue but we are unsure which parts to start with first. We are unsure if I need to install a second oil cooler, water pump, thermostat, or radiator? Where would be a great place to start before I start throwing 2K or more into the car to replace them all? I would like to and I will replace them all since the car has the mileage on it however I cannot do them all at once...so I would like to replace the one or combo of them that is causing the car to run hotter than normal first.

Any suggestions? Thank you in advance.
Old 07-31-2011, 10:33 PM
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If it gets hot while you're stopped, the first thing to check is the cooling fans. Make sure they're coming on. I don't remember the details, but there's an aftermarket fan controller available that brings them on sooner than stock.

If it never goes below 205 degrees, even on cooler days, check the thermostat.

Ken
Old 07-31-2011, 11:20 PM
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Did you have your AC turned on?
AC would add about 10degrees when in idle...
Old 08-01-2011, 03:49 AM
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The first thing to check is to make sure you have good airflow across the radiator... Not just that the fans are operating normally, but also that the fins are not clogged with debris.

The next thing I'd look into is replacing the thermostat. If it's still the original one... After 120,000 miles, it's time to lay it to rest anyway.
Old 08-01-2011, 04:27 AM
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Fans
Thermostat
Water pump
Radiator
rad hoses

not many other choices
Old 08-01-2011, 08:32 AM
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Check the $100 thread in my sig. There were several things that together helped me, some are listed above. I think closing up the holes did the most.
Old 08-01-2011, 02:22 PM
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I will definitely be replacing the thermostat and since I have to remove the water pump anyways to get to the thermostat, I may as well do it at the same time...especially when I can just get the combo from Mazmart. As for having the AC on, yes it was on however I do not think that even with adding 10 degrees for the AC I shouldn't be running at 220 degrees at times. Unless the weather is in the 80's, my car never runs colder than 205 degrees except at initial start up. As for the fans, how do I test if they are working properly? I have witnessed them on and running and them turning on while the AC is on. Is there something to look for or listen for on the fans?
Old 08-01-2011, 02:24 PM
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Originally Posted by Highspeed
I will definitely be replacing the thermostat and since I have to remove the water pump anyways to get to the thermostat, I may as well do it at the same time...especially when I can just get the combo from Mazmart. As for having the AC on, yes it was on however I do not think that even with adding 10 degrees for the AC I shouldn't be running at 220 degrees at times. Unless the weather is in the 80's, my car never runs colder than 205 degrees except at initial start up. As for the fans, how do I test if they are working properly? I have witnessed them on and running and them turning on while the AC is on. Is there something to look for or listen for on the fans?
The thermostat is a good thing to replace, but you don't have to remove the wp to get to it. They are in two different locations.
Old 08-02-2011, 11:30 AM
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On the topic of fans...

There is a mod to have the fans run on low at all times. This might help with the whole cooling thing. Right now the fans do not come on until the car is pretty hot. Changing the thermostat will not help.

Try this: https://www.rx8club.com/showpost.php...3&postcount=25

If you have a soldering iron, you are in for about 3 dollars tops. If not, $10.

If it makes a difference, then you need to address the fan on temps. You can just use this mod, buy a kit, or get an AP. I like the AP idea best.

I just pulled my low temp thermostat out BTW and went back to stock. I learned that if the car is too cool, it actually will stay in open loop mode and the ECU is not part of the program.

Mike
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