93 camry xle v6 overheating

[davemac2]

This car has driven me nuts for the past two years. I've gone thru 3 rads, and now it is overheating after a 40 min highway drive. It won't overheat under street driving conditions. The rad has been replaced since the old one appeared to leak, but this has made no difference. It seems to have lost coolant, but I'm not sure if it is overflowing out of the reservoir or somewhere else. I test drove it last nite again and as I was pulling back into the garage from a 40min highway run, it just started to overheat. I looked the rad area and engine over and could not find any coolant leaking whatsover. It also did not seem have lost much coolant if any. The area around the waterpump appears completely dry as well. The exhaust has no coolant smell at all. The car starts up just fine in the morning after sitting, so it doesn't seem like coolant is seeping into the cylinders. I did a block test this morning and it was negative. I retried that test twice after running the engine for 40mins at idle to get it hot, and again negative. I also pulled all 6 plugs and they all appear dry and exactly the same. The coolant in the system has been completely clean as well as the engine oil. Ie. no cross contamination. The symptom points to a blown head gasket, but the testing so far says no. I'm going to try a compression/pressure test to see if I can blow air from the cylinders back into the cooling system and check cylinder compression. Besides that, I'm at a loss as to what else I can do to narrow this one down.

Some ques:

1. I guess this could also be a corroded or slipping water pump not circulating enough water with the cooling system gettng overwelmed, but I assume this is not too common?

2. Has anyone else had overheating symptoms similar to mine on this V6 3zvfe engine that turned out to be something besides the head gasket?

3. One thing I need to check again is whether the hydraulic rad fan is coming on full speed when the overheating begins. After 45-1hr of highway driving, does this fan usually come on at high speed with moderate ambient temps? Can anybody comment on their experience with that? I would think at highway speeds, there would be enough air flow to cool the rad without the fan at all under normal operation.

I am hesitant to pull the head(s) unless I can determine for sure it is a head gasket. Too much bloody work! Someone mentioned on an older thread about pulling the thermostat to have a look at the water pump impeller since you can see the outer part of it from the thermo housing. Is that true?

Any help is appreciated.

dave mc

[BamZipPow]

With all that you've put into it so far...I'd go ahead and pull the water pump then...

[Luckynumber5]

The water pump is a decent DIY job ont he 3vz, nothing in particular is a pain its just a tiring job.

If the problem is not in the water pump it is possible the system has a clog on one of the many cooling passages on the block, you could try a total system flush and run some mineral deposit remover through to try and break up and large chunks of rust or deposit that can develop. It is a cast iron block after all.

[Camryv6xle]

i had all those symtptoms and all i needed to do was replace the waterpump. but while i was at it i changed the belts and everthing too. i say from my very similar experience to change the water pump. i have a 1mz fe btw, dont know if that would make a difference in this case but ill throw that out there. good luck with this.

[davemac2]

I took the waterpump off today. It looks almost brand new. No corrosion, and the impeller seems to be attached to the shaft solidly. I'll replace the pump and timing belt anyways as well as the thermostat, but now I'm at a loss since the block test was negative for exhaust gases. The only other thing I'm going to check for is a collapsing lower hose at high RPM when it is starting to overheat, and maybe do a chemical flush on the block.

Otherwise, I guess I will need to take it to someone else to get a 2nd opinion.


dave mc

[xtremeskier97]

Man I have the exact same problems with my 3vz, but I AM losing coolant sometimes because it's boiling out of the overflow. This happens about once a month to me, and I have to refill the coolant and bleed the system.

Im thinking mine IS the water pump, but I havent done all the tests you have.\

I also question whether or not the hydraulic fan is actually working like it should. Id love to just convert to electric like Eye8 has.

[davemac2]

Originally Posted by xtremeskier97

Man I have the exact same problems with my 3vz, but I AM losing coolant sometimes because it's boiling out of the overflow. This happens about once a month to me, and I have to refill the coolant and bleed the system.

Im thinking mine IS the water pump, but I havent done all the tests you have.\

I also question whether or not the hydraulic fan is actually working like it should. Id love to just convert to electric like Eye8 has.

For me though, the fact that it is overheating on the highway eliminates the fan entirely since the rad should be getting plenty of air on its own. I bought some chemical cleaner yesterday, so I'll give that a shot next.

dave mc

[toyomoho]

You did a chemical test of the coolant for exhaust gases and this was neg?

Does running the heater full on help lower the temps?

Does the car have the bottom plastic air skirt installed below the radiator.

Plugged CAT.

http://en.allexperts.com/q/Toyota-Re.../f_4103504.htm

[davemac2]

Originally Posted by toyomoho

You did a chemical test of the coolant for exhaust gases and this was neg?

Yes, 3X, negative

Does running the heater full on help lower the temps?

A bit.

Does the car have the bottom plastic air skirt installed below the radiator.

yes, but for the camry, I don't think that can really cause an overheat per say since that rad has direct cooling thru the grill.

Plugged CAT.

http://en.allexperts.com/q/Toyota-Re.../f_4103504.htm

Interesting, I'll have to look into that one, but I doubt it. The car seems to have lots of power.

I'm not sure i f I trust this new cheapie rad I bought off Ebay. I'm wondering if its cooling capacity is bad. I'm about ready to throw in the towel on this one and get a shop to take a shot at it. It almost left me stranded today. The only thing I may do before that is try another rad and replace both coolant caps. Then again, I think I've reached my limit both in frustration and time.

dave mc

[llcoolpass]

****O K one thing I know very well isthe cooling system failure modes on this car, so davemac2, listen up, to answer one of your questions.

secondly, you tested the comrpession and see no signs of head gasket failure.
ok, let's move on.

you have new radiator, but old hoses.

you notice the problem more on the highway.

question1: what does the dash temp gauge read?
question2: is the a/c on?
question3: what is the ambient temp in your driving range?
question4: what is the vac pressure at idle [to check for clog catalytic converter as toyomobo rightly asked]?
question5: how fast is it that you are going on highway?
question6: when warmed up, if you rev the engine to 2000 in neutral with parking brake on, does the cooling fan come on high speed from a slow speed? if not, check the temp gauge see if it starts going up. also, at the same time, if it starts going up, do not rev engine anymore, but turn off engine for a few. Then, come back here and post....
question7: did you bleed the cooling system properly [with the heater on full hot full fan, and fill with 50:50 or 40:60 coolant:distilled water]?


fact: being on the highway does NOT preclude car overheating. under some conditions it can still happen , folks, on the car in question i promise i'm not lieing.

so if you answer those questions, I can take you to the next step ....

[xtremeskier97]

Where do you get the head gasket leak detector and how much does it cost?

[BamZipPow]

I was gonna question about the hoses as well but I would think if you replaced the radiator 3 times the hoses would've been a cheaper choice.

[llcoolpass]

xtremeskier, there is a cooling system pressure check tool that's usually 30 dollars.

the rest is leakdown testing using comrpessed air source and building pressure into the combustion chamber.

or in simple easy way is compression check and vacuum check [less accurate ways but helpful] and checking spark plugs and combustion chamber after engine is turned off to see if coolant is therein withdrawn by the pressure difference due to cooling and so on.

[davemac2]

Originally Posted by xtremeskier97

Where do you get the head gasket leak detector and how much does it cost?

http://www.amazon.com/Universal-Test.../dp/B000I17Z68 $25

dave mc

[new echo owner]

Sounds like your radiator caps are letting the coolant out but not letting it back into the cooling system. Have you check the hose in the coolant reservoir to make sure it is flowing both ways?

N.E.O.