97 Toyota Camry overheating, WHY?

Hello, I have a 97 Camry that looked like it had a small oil leak coming from the head gasket. It needed oil added every few days or so, so I changed the head gasket and now it overheats!

I changed the T-Stat, no luck

I took the radiator out and flushed it. It seemed to flow great too. I had the garden hose on full blast going in the top and it was coming out of the bottom just as fast with no back pressure out the top. So I think the radiator is good.

I’m pretty sure the fan was kicking on at the correct time but just to be sure I hard wired it so it’s always on if the key is no, still over heating

Compression test shows 200, 209, 209, 211. That’s pretty good right?

Just to be sure that the exhaust was not leaking through the new head gasket and heating up the coolant I did a liquid block test. Where you suck air out of the radiator cap and then it goes through a chemical which will change color if it contains exhaust gases. Not only did the liquid not change color, it was very hard to get any air out of the radiator, indicating that the system is tightly sealed correct?

The car is not loosing any coolant

I changed the coolant gauge sensor as well, still shows overheating.

Before I changed the sensor out I bought a thermometer and put it in the radiator. I was able to leave the cap off even after it started to get hot. The coolant did start to rise a little but I just bled it off from the drain plug at the bottom as it got higher, making sure to leave it full and not get any air. And the temp stayed below 200. This made me think that it was not overheating and thus the new sensor. This was not the case though. I realized that the coolant coming from the engine was very hot and then going into the radiator where it could cool down via my always running fan and then go past my thermometer.

The heater works great and even helps cool the engine down. This means that the heater core is not blocked and that the water pump works correct?

So after all of this I decided that there must be something blocking a coolant port. SOOO I took it all apart again only to find no blockages. I can see very well down into the block and fairly well through the cooling ports on the head and everything looks fine.

I also checked out the water pump and that looks great. Still in great shape and the bearing is not worn at all.

There was only ONE thing that was wrong on the engine (that I found) and that was the throttle body gasket. It was put on the wrong way so as not to fully block that air passage that I believe is pulled from the block into the throttle body. Does anyone think this could cause overheating?
Or any other suggestions before I put it all back together. Thank you very much.

‘It needed oil added every few days or so, so I changed the head gasket and now it overheats!’

My first guess is you have an engine oil flow problem. Gunked up engine so to speak. No easy fix for that.

I’m going to ask what maybe a dumb question. Are are sure you put the head gasket on the right way?? Another question, are you sure you put the drive belt on the right way. I have heard of belts being put on wrong, and while tight they spin the water pump backwards which causes it to not flow water correctly.

One more thought: are you certain that you have the correct headgasket? Did the parts place look it up by the VIN number? Manufacturers often make suttle changes during production runs that can have huge impacts on coolant flow.

Is it really overheating?
Could be a damaged temp sensor.

Warm it up with the radiator cap off.
Can you see coolant flowing from the top hose?

Yes I’m fairly certain that is it actually overheating. Like I said i took the cap off and took the temp of the coolant in the radiator and that was good, below 200. But then I felt the top hose and it was very hot, way to hot to touch. Not to mention I changed the temp sensor anyway and it still shows overheating. I have also checked the wire to the gauge and the gauge, both of which are good.

It is the correct head gasket. Confirmed by the manufacture date and the engine code, not the vin but the engine code under the hood. 5F-SE I believe? In either case it was checked.

The water pump runs from the timing belt and I didn’t have to take that all the way off. Not to mention I do not believe it would even be possible to put it on the wrong way so as the water pump would spin in the other direction.

The oil looks fine, I don’t think that is the problem. I wanted to avoid this embarrassing fact but I guess I can’t any longer. It was not the head gasket that was leaking oil. I changed it out and then it kept leaking oil. come to find out it was the oil pressure sending unit located in the head directly above the HG so it was dripping down onto where the head meets the block. So it looked it it was coming from the HG. After I changed out the oil pressure sending unit it stopped leaking. Wish I just did that in the first place…

Does anyone know what the flow rate of a stock water pump is? Is it more than a garden hose on full blast? If so I may have blocked up the radiator? And flowing the hose through it makes it look like it’s flowing good but if the engine flows faster then that it may still be clogged?

Take the radiator out and have it flow tested ot get an infrared temp reading gun and check for cooler areas of the radiator.

I think that you either have the wrong head gasket or you put it on upside down. Upside down would be more likely as the gasket looks symmetrical end to end, but its not and it would partially block the passages between the head and the block.

I just put the head back on today. I did end up taking the water pump out all the way to look at the passages and everything is clear. I can shine a light in one hole and see it in the next and then I just kept going like that all the way around the block and then the head also.

The head gasket can only go on one way. There are two cylinders that stick up out of the block about a half inch and are about the same in diameter. If you flip the HG the other holes are too small to fit over these. And I checked every passage with every hole in the HG and they all line up.

I think I’m going to keep putting it back together and then if it still over heats I’ll go after the radiator. No sense to pay to have it checked now right?

Whoa…you changed the head gasket and now it overheats. What IMMEDIATELY comes to mind is that you have an Air pocket in your cooling system. This can be burped out.

Your “test” of the radiator is a little bit flawed…you cannot judge the ability of any radiator to shed heat by doing what you described. The ability of the rad to shed heat is in the tiny little passageways you see when you look at the rad…those solid looking lines in the rad carry water…and they clog up with crap and with mineral deposits if you use common tap water in the system…if they are clogged…it wont shed heat. Your test did not do enough to show how well those passageways are flowing…and radiators DO GO BAD because of this. Half of them might be clogged while the others are flowing properly…but my money is in the Air pocket issue…that is Super important

So first…I would try burping your cooling system properly…you may have a bleed nipple you may not…you need to look and read up. IT IS A MUST for the cooling system to work properly. Your rad may also be suspect…theyre rather cheap so if you do swap it out it wont hurt anything.


I also thought about air trapped in the cooling system.

OP had no issues reported on overheating before gasket change. Just an oil leak. Stick to the fundamental issues.

Did you compare the original head gasket to the new replacement gasket? Is it possible that your car may have had a cylinder head or engine replacement previously that you don’t know about, and that the different engine may use a different gasket?

How does the car run? Does it rev up normally and have plenty of power? Any check engine light? Having the camshaft off by a couple of teeth could make an engine run significantly hotter. or having the cams mistimed to one another could cause this. Did you remove the cams from the engine?

Did you replace the thermostat and install the new one backwards?

Sorry if these questions seem stupid…