Next troubleshooting steps? Base '00 coupe getting hot

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Sep 8, 2025 | 02:51 PM

#21

redzg

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From: Orlando Florida

I, for one, would have to think about trying a new temperature sending unit.

Sep 8, 2025 | 02:51 PM

#22

viffer

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From: East TN

Quote:

Originally Posted by lucky131969

Sounds like you missed the point of the exercise. The point of using the IR thermometer was to check correlation between indicated(gauge) and thermostat housing(IR gun). Cold engine, rise, thermostat opening, etc......not just at max indicated temp. It does sound like you are getting a good heat exchange though. I assume that when you took the 225 reading at the thermostat housing, the fans were running on high?

Yes, the fans were on high when I made that temp check and came on high at the correct indicated temp.I did make checks as the engine heated up, and it seemed the thermostat housing was mostly about 15-20deg or so cooler than the indicated temp as the engine heated up. It did open at about 185 again as well, the IR showed about 15 lower than that at that point.

Sep 8, 2025 | 03:57 PM

#23

lucky131969

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From: Dyer, IN

Quote:

Originally Posted by viffer

Ok then. Nothing more to add. Perhaps a trusted shop can help you out.

Last edited by lucky131969; Sep 8, 2025 at 05:02 PM.

Sep 9, 2025 | 09:51 AM

#24

viffer

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From: East TN

So it appears that the radiator might be doing it's job if those in and out temp readings are accurate, so I guess that would seem to indicate that there may not be enough circulation, or possibly air pockets. Unless there are better idea's I'm thinking of swapping the thermostat and surge tank cap, and possibly the coolant temp sensor as well as long as I have the system drained, and see if that has any effect. At this point I'd like to take it to a shop but just getting it to the closest shop that knows these cars would cost a lot more than these parts and my time, so that's not really a feasible option this time unfortunately. Not sure how else to proceed here, but as always any other input or idea's are greatly appreciated.

Sep 9, 2025 | 12:40 PM

#25

tabbruzz

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From: Central NJ

Are you 100% sure that there is no leak? Possible a tiny one at the bottom or the surge tank or a crack in the plastic section of the radiator? Are you using dexcool? Could use traditional as well, but they should not be mixed. To me it seems that there may be some amount of air in the system.....

Sep 9, 2025 | 03:29 PM

#26

viffer

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From: East TN

Quote:

Originally Posted by tabbruzz

I'm not 100% sure, but fairly confident there aren't any leaks. The fluid level hasn't gone down at all over time and there are never any drips on the floor under it. I finally have the tools to jack the car up, and will be able to take a closer look underneath as well, and see if there are any signs of fluid or leaks. I can also try to bleed out any air before I do anything else, in case you are right. Also it is Dex-Cool, and that is what I will be using as well if I end up draining the system. Thanks!

Nov 15, 2025 | 10:55 AM

#27

viffer

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From: East TN

Well I finally have a followup, I ended up taking the car to the shop after all. Looking closer at things almost everything in the cooling system was still original and in bad shape. The hoses were all shot, the hose clamps all very corroded. I'm actually surprised none ever came apart! The coolant overflow tank was seeping at the seams, etc. The mechanic did determine the high temp issue was the thermostat after all, so as long as he was draining the system might as well replace everything and be good for years to come. He changed all the hoses and clamps, put on a new overflow tank and 18psi cap, put in a new water pump and thermostat and housing, temp sensor, coolant and oil change and a number of other unrelated smaller issues. The radiator is the only thing that wasn't replaced. I've got a few days running now, and it's never gotten above 210 is city traffic, and holds about 200 on freeways. Cost a few bucks but the piece of mind is definitely worth it when I take it on road trips. Now it looks like the interior is going to need some long over due attention, there's always something!