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2000 Toyota Camry slight overheating

A couple days ago I saw that my Toyota Camry was overheating, the gauge was going about 3/4s of the way and then returning to normal. I had then replaced the T-stat but noticed the fans were not running, so I replaced the relay as it tested bad. The fans then started to work when the A/C was turned on, but I noticed the car was still going 3/4s of the way then returning to normal. So, I took it to a mechanic and looked for his opinion on it, he tested it and said that everything is working fine and when the engine gets hot enough the fans kick on, bit the gauge still hits 3/4s hot and then returns to normal. My mechanic said that he has seen this before in other car models and that everything is working as intended. I was just wondering if this is a common occurrence with some cars? Or should I look for other possible problems? I’ve never personally owned a car that looked like it was overheating then quickly corrected itself.


Change the radiator cap and see of that helps, cheap and easy to do. The cap regulates the pressure of the system, and if it is going bad, it can cause temp spikes like you are seeing.

Agree with @BustedKnuckles. You might need to change your thermostat also in the near future. I had to do this when my Jeep Cherokee started doing the same thing. It eventually got to the point where the thermostat closed up and did not reopen.

I’ll definitely try the radiator cap, thank you. I just replaced the thermostat in addition to the relay. So, hopefully the radiator cap keeps the temp. gauge normal.

Has this car always had temp gauge swings?

Not that I know of. Another thing I’ve noticed is while it sits idle after it’s been running awhile it’ll heat up all the way until near redline and then the fans will kick on, could there be some kind of delay with the sensor?

It’s passed a cooling system diagnostic and it’s temperatures read normal. The fans just wont kick on until it hits about 210-220 degrees and that seems to be nearing red line. The temperature gauge displays that this is occurring, which makes it look like it’s overheating. I’m wondering if there is a delay in that though?

The upper radiator hose design on the 5s-fe motor is a booger. It has a giant hump in it that needs to be pushed down and almost milked like a cow so all the air pockets can work themselves out. It sounds like that’s what you should be doing first, as this is very important, anf the first thing I do whenever I repair a 5s-fe motor (assuming it’s not a v6-1mz-fe). Do this when the vehicle is COLD COLD. Never take the cap off when hot, obviously. Burping the air, squeezing the upped radiator hose while pushing the entire thing down is crucial, but it takes 2-3 minutes. If you have an air pocket, it will trap behind the t-stat, eventually pressure and coolant that’s up to temp will open it, but the gauge may be high. There are 3 temp sensors on the 4 cyl camry. one for gauge, one for fans, and one for EFI. But the bigger question is, why did it start? You may have a leak. When the temp gauge moves past half, it’s usually bc air has replaced the lost coolant. How’s your H2O pump? making noise? Any tell-tale red crusty coolant marks? We need those answers first, but I be when you properly purge the air, and fix any leaks that may be there, you’ll be back to normal. I highly doubt any of the 3 sensors are bad. BTW, I’m a Toyota Master Tech with almost 20 years experience. Good luck.

btw, once you milk the hose and get the air out, you need to run the vehicle at idle with the cap off and continue to burp the air. And then run the car at 2000 rpm for a couple of minutes, letting more air purge. The let it sit at idle for a few more until fans kick on. Then top off system, put a good cap on, and let us know if it’s fixed.

Why did Honda design a cooling system that requires a tech with a phd to bled the air? Car delivered from factory is fine. As long as the owner never has a leak it’s cool. Any repair that affects coolant level now requires a factory trained tech to massage? Oh, and don’t worry about overheating alum head motors. Nothing serious. That’s how Honda/Toyota gets new car sales.