Rather than continue to jack the local mechanics thread, I'll make a new one.

Here's the background - I have a '92 Toyota Camry, V6 Engine. I recently had to replace the radiator after the top reservoir cracked in spectacular fashion. While I was at it, I replaced the thermostat, which I had discovered was stuck.

So, all is well and good, I think. I put all the pieces back, flush the system with water for good measure, drain, etc. I then filled the radiator with coolant and the coolant reservoir, drove it for a bit to work the air out, opened up the radiator and filled it again to top it off.

Here's the problem - when I drive it for a little bit, it's great - temperature is normal, etc. After awhile, the temperature starts creeping up into the red, and when I stop, the coolant in the reservoir tank is boiling over. Sometimes when it's crawling up to the red, it'll climb back down a little - never back to "normal" operating temperature, but enough to notice. But, it always seems to climb back up to red.

I've looked specifically for coolant leaks, and I'm not seeing any from any of the hoses or the water inlet pipe. I have seen it drip a little bit of coolant from the return hose to the reservoir - i.e., I think I'm losing some coolant via boiling out, and some of it's condensing again back under the hood. But I'm not seeing any other place where coolant would be leaking.

So, what should I be looking for? Problem with the water pump? Or have I won the car repair lottery with something worse, like a blown head gasket?

7/15/2008 3:07:14 PM

sounds like a blown head gasket, let it warm up with the cap off and look for bubbles in the coolant

[Edited on July 15, 2008 at 3:12 PM. Reason : could still be air in the system, depends on how you bled it]

7/15/2008 3:11:40 PM

I second the head gasket thing. That engine is rather famous for it.

7/15/2008 3:50:59 PM

Two questions before I agree with head gasket:
1. Does your exhaust gas smell any different or look different?
2. What cooland did you use when you refilled it? Just coolant, premixed, color?

7/15/2008 4:02:10 PM

this is exactly why you don't just dive into such a repair job not having a clue wtf you're doing. stop messing with it and get some help, if the head gasket isn't already blown it will be by the time you get done "learning" by heating it to a boil a dozen times. i fear that might have been your original problem though, and the pressurizing of the cooling system helped ventilate an already fatigued radiator.

answer us these: are you positive you put the thermostat back in the right way? if you cut the heat on do you hear any noticeable gurgling noises under the dash? does the heat work well, or is it just ambient? does running the heat pull the temp down any? are you getting any white smoke/steam from the exhaust? how does the oil look?

7/15/2008 4:14:05 PM

Quote :

"Two questions before I agree with head gasket: 1. Does your exhaust gas smell any different or look different? 2. What cooland did you use when you refilled it? Just coolant, premixed, color?"

Exhaust gas, no. Coolant itself was boiling out in a white smoke, which smelled like coolant.

Coolant I used was Prestone extended mileage - first one I got was pre-mixed, when I got a second bottle (concentrate), I diluted it to 50/50 before adding it. Color was "neutral" - in that it was labeled as "works with all colors" (red/green), the actual coolant looked like Mountain Dew. My system has/had green coolant.

Quote :

"I second the head gasket thing. That engine is rather famous for it."

Fuck. me. I'm pretty much screwed if this is the case.

Quote :

"this is exactly why you don't just dive into such a repair job not having a clue wtf you're doing. stop messing with it and get some help, if the head gasket isn't already blown it will be by the time you get done "learning" by heating it to a boil a dozen times. i fear that might have been your original problem though, and the pressurizing of the cooling system helped ventilate an already fatigued radiator."

Okay, you know what? I have replaced cooling system parts before. I'm not even going to pretend to be an expert mechanic, but there's no reason to treat me like an idiot, especially when you can see I've already got enough problems as it is. I'm asking for help, but it doesn't make me completely clueless.

Quote :

"answer us these: are you positive you put the thermostat back in the right way?"

Yes. I put it in exactly as it was before, made sure the jiggle pin was up top. Haynes manual showed it going in exactly the same way - spring side facing toward the water pump.

Quote :

"if you cut the heat on do you hear any noticeable gurgling noises under the dash? does the heat work well, or is it just ambient? does running the heat pull the temp down any? are you getting any white smoke/steam from the exhaust? how does the oil look?"

Yes I hear gurgling noises. Yes the heat works well, but it doesn't seem to take down the temp a whole lot. I don't see the white smoke/steam coming from the exhaust - just the engine block. Oil looks like a medium brown.

[Edited on July 15, 2008 at 4:30 PM. Reason : coolant color]

7/15/2008 4:28:49 PM

define medium brown.. like chocolate milk looking?

7/15/2008 4:44:53 PM

Darker. Like a melted Hershey's chocolate bar.

7/15/2008 4:51:46 PM

Quote :

"Okay, you know what? I have replaced cooling system parts before. I'm not even going to pretend to be an expert mechanic, but there's no reason to treat me like an idiot, especially when you can see I've already got enough problems as it is. I'm asking for help, but it doesn't make me completely clueless."

it's great you're learning something new, but maybe you should have thought about asking some of these questions before you went at it, not after. then you would have learned that you were essentially wasting time until you did a compression test and pressurized the remaining parts of the cooling system, especially with that particular engine.

lets hope you get lucky and it's not the head gasket, but the fact remains you took a big risk to go through all that trouble without checking other things first. you've taken another big risk by heating it to the point of boiling over numerous times. if a head gasket wasn't blown before, it could be now. or, you could have instigated something even worse like a cracked/warped head. i'm not trying to be an ass, it's genuine advice and should only help you if anything. i bet you'll be more cautious about taking on other repairs now, won't you?

it'd be one thing if this was just some random pos you didn't care about, but it sounds like this is a vehicle you rely on and it would cause you some grief if it had a catastrophic failure.

Quote :

"Yes I hear gurgling noises"

that's air. leave the temperature control in the hot position, and run the car again with the cap off and see if you can get it to burp any more air out. it'll help if you park it on a good incline or jack the front up as high as you can. some vehicles can require even more extreme measures to full evacuate any air pockets. in addition to an obvious loss of volume, air pockets get hung up in the water pump causing it to cavitate. which equals little to no coolant flow.

Quote :

"Darker. Like a melted Hershey's chocolate bar"

eh, that's kind of a suspect description. how many miles on the oil? can you post a pic of the dipstick pulled out? don't wipe it. we can tell you in two seconds if it's got water/coolant in it.

[Edited on July 15, 2008 at 5:03 PM. Reason : .]

7/15/2008 4:58:19 PM

Oil is fairly new - had it changed < 1000 miles ago.

I did try burping the air out more - i.e., topped it off, ran it without the cap and let it bubble out, topped it off again. This is essentially what I had done before. Vents throw out insane heat when I have it on hot, full blast - although that's probably a good thing. Kept my foot on the accelerator in park and revved it to about 2K RPM for about a minute or so while I was burping it, when I finished, the coolant level was staying steady. Temperature sits around normal on the gauge.

When I did this before and took it around the paces of the neighborhood, temperature stayed flat. It was really only when I got up to cruising speed (i.e., 40-50 mph) that the temperature seemed to creep up - and when it did, it wanted to stay up.

[Edited on July 15, 2008 at 5:35 PM. Reason : .]

7/15/2008 5:34:22 PM

oil looks fine.

if you can still hear gurgles or a rush of water under the dash (heater core) as you first start the car or as you cut the temperature control slowly back and forth between hot and cold, it's still got air in it. all i can tell you is i've seen some big pockets be very stubborn. sometimes it takes closing it up and cracking the system open at another point like a hose connection to let it bleed off, just the right angle front to rear and/or side to side, fancy work with a shop vac, etc. air bubbles aren't pumped and pushed through a system like you'd think. that goes for anything from radiator hoses to human iv lines.

you've probably lost track by now with refilling from overheating or a lot was wasted trying bleed it, but do you happen to recall how much liquid it took to get it full initially? sometimes there's enough air left that you can cross reference the amount poured with the capacity of the system and there's a noticeable deficit.

positive the cooling fan is hooked back correctly and operating properly? the shroud? belt tight and not slipping if you removed or spilled coolant?

if you're absolutely positive you've got all the air out and everything is back together right, it's time to pull the plugs and see what they look like. if one (or more) look like they've been steam cleaned or otherwise have a very light colored tip/electrode, there's your problem (head or head gasket). post pics of the plugs, a trained eye here can read them too.

past that, there's not much more we can coach you to do over the internet that wouldn't be wild stabs in the dark. diagnosing such a problem simply takes experience and being there in person to manipulate the car and eliminate things as needed. not to mention some specialty tools i highly doubt you have or would be willing to buy.



[Edited on July 15, 2008 at 6:24 PM. Reason : .]

7/15/2008 6:14:56 PM

Thanks. I'll take a crack at the plugs later when the engine cools down and post pics when I get them out.

I appreciate the help...

7/15/2008 6:18:17 PM

hmm, i'd never heard of the spark plug method of diagnosing a blown head gasket. i thought the chocolate milk oil was a pretty clear indicator yay/nay.

7/15/2008 9:11:56 PM

nah

last one i blew was pretty small as far as blown head gaskets go.. it would stay cool as long it had coolant but was pretty much pressurizing the coolant system the whole time and spraying water out so it didn't stay cool for long

20psi boost was a bad idea (3000GT VR4)

7/15/2008 9:59:07 PM

Quote :

"this is exactly why you don't just dive into such a repair job not having a clue wtf you're doing. "

I have to agree. Properly servicing a modern cooling system isnt exactly beginner shit.

7/15/2008 10:38:28 PM

^^^when you get coolant pissing into a burning hot cylinder, it makes for one hell of a steam cleaner. in fact, pouring a really fine stream of water into your carb or brake booster hose with the engine running at operating temp used to be an old school way of clearing any carbon buildup out before chemical cleaners like seafoam, etc. came around.

you can have just a single symptom or a combination of a few. it all depends on whether it's the gasket or the head, where it fails, and how big of a failure. i've seen ones that will just quietly sip away at a quart of coolant once a month with no other symptoms. on the other extreme, demo derby (and one personal daily driver, lol) cars that IF you could get them started without hydrolocking, the entire contents of the radiator and oil pan were evacuated within a minute. exhaust pipes looked like a garden hose and you could probably stick a flat head screwdriver between the heads and the block.

7/15/2008 11:31:21 PM

I believe I found (and fixed) the problem. Not a blown head gasket.

It was a gasket, however: the thermostat I put back in apparently didn't sit just quite right, and the gasket got pinched. The result was coolant leaking from the thermostat housing.



It was a bit of a pain in the ass to get just right, but I managed to get it back and put a little ATV sealant around the housing just for insurance - no leak.

I actually found the leak after warming the engine up - i.e., it wasn't really noticeable until the engine got warm and the thermostat opened up, thus spilling coolant out. Which would explain why it only seemed to shoot up at cruising speeds - when the system tried to pressurize, coolant came pushing out the gasket. What made me think of it was what you were saying about pressure testing, which made me think if the problem only starts when cruising, it must be when the system is trying to pressurize, therefore exposing a leak.

So, there we go - problem solved. Next step will be to test the system with a pressure gauge just to make sure it's not leaking, but I think this was the problem - no pressure, coolant starts to boil over.

[Edited on July 16, 2008 at 10:45 PM. Reason : Added image]

7/16/2008 10:44:56 PM

Glad you found the problem, but I'd say the easiest test would to be take it out for a test drive

7/17/2008 12:12:25 AM

Did take it for a test drive, it heats up a bit and then cools down - obviously, I need to work the air out completely still. Still, not racing up to the red zone, so I think I'm in the clear - I just need to watch the coolant levels. Pressure checking would still probably not be a bad idea, but at least it looks like it's pressurizing now.

7/17/2008 12:40:54 AM

Quote :

"I've looked specifically for coolant leaks, and I'm not seeing any"

not sure how you can miss something that's leaking so badly it's causing overheating, but whatever... glad you found it. cross your fingers the overheating didn't injure anything else.

Quote :

"Next step will be to test the system with a pressure gauge just to make sure it's not leaking"

honestly, this should have been your first step and would have saved you/us any speculation and headache about where or what the problem was. i understand a cooling system pressure tester isn't exactly something that's on everyone's list of tools though.

i hope this isn't just a learning experience in how to physically change a radiator/thermostat. taking something apart and putting it back together is the easy part. the more important lesson is that of fully understanding the concept of how a system or component interacts with the rest of the vehicle before you mess with it. that's the downfall of most weekend wrenchers and even many mechanics. again, not trying to come off as an elitist or an asshole. we've all been there, and some of us have had to learn this lesson the hard way, more than once. i speak from sympathetic personal experience.

7/17/2008 1:47:21 AM