"Normal" overheating?

[dcarrb]

Find out what's the matter before worrying about how much it's going to cost. Could be something as simple as a defective thermostat.

dcb

[Nomake Wan]

Well considering I emptied my entire 50/50 mix of coolant into the radiator and excess tank, I'd say I was running out of coolant. Levels are back to normal now.

After some solid highway driving I checked the radiator fluid... it was pure green. I recall that head gasket failure creates "milky" fluid?

And by dirty I meant the outside of the tank. Now that I've put coolant in it it's easy to see what the level is.

I'll keep an eye on it.

[Hocrest]

Hopefully it's not a HG but...

On mine, the oil showed no traces of coolant, the coolant showed no traces of oil, the exhaust had no traces of coolant, the coolant had no traces of exhaust gasses. But, I was still losing coolant, about 1 gallon for every hour of driving. I searched everywhere for leaks, as long as I kept some coolant in the reservoir, the temp would stay normal. I got some UV dye to add to the coolant to help spot leaks. Still couldn't find any.

Only after pulling the engine and pulling the heads did we find the fault. there was a external coolant leak, out the bottom of the head in the area between the exhaust manifold and the oil pan. Virtually impossible to see when the engine was running, which is the only time it would leak.

I'm not trying to scare you, just letting you know to look for all possibilities.

[kwren]

Originally Posted by Hocrest

You're correct.
If working properly, both fans come on together. But they are 3-speed. Depending on Engine temp, AC, Vehicle Speed and other factors, the ECU runs them slow, med or fast.

If a car is overheating while moving it will not be because of the fans. Any consistent speed will move more air through the radiator than the fans can on their own.

been there done that!
We have verry little air flow through our radiators and when one of my fans stoped working the car over heated on the freeway. Turn ac off and temp went down a bit

[Nomake Wan]

Just took it over to Garage Tuning, a local Subaru-specialist tuner shop. Great guys, met them at a meet in San Diego. They took a look at it and don't think it's head gasket, and if it is then it's incredibly minor because the radiator isn't leaking (and is full) and the resevoir is also full still. Considering how many Subaru engines they had sitting around the shop, I'm inclined to go with that. He said watch it over the next month. If in a month there's no change, don't worry about it. It's due for a 90k mile service in 3k miles anyway.

So the verdict is... keep driving it, keep an eye on it.

Now to worry about the rest of the car... *rubs hands together*

[SSSVX]

good to hear is a better news.

[It's Just Eric]

Yeh, my black car would overhea mysteriously...Only in toms River, NJ. Funny thing, my old red car felt the same way about that town....I think it's my pwr radiator..I swapped it from the red car to the black

Anyhow, yeah, I have a similar overheating issue. Seems if Im on a long highway trip, it'll run 3/4th hot. I turn on the heat to help vent some hot engine air out....Now, this was odd. With the temp at 85, the air coming out wasnt hot...at all. Then suddenly, the heat kicked in and the engine temp drpped immidiatly.

I also seem to be loosing some coolant, but it's likely just evaporating due to running hot. I did my thermostat a while back, which seemed to help, untill I had to drive through toms river to go to the shore meet

Anyhow, I have two guesses as to whats going on. A) a pratcing witch doctor at the pwr factory has a vendtta against NJ, or B) mabey I have a heater core clog? radiator has a rats nest in it?

[TomsSVX]

Eric, the PWR leaking is VERY typical. Do you have the ears chopped off your cap? Try that first to see if it stops. Keep checking fluid in the ol' girl

Tom

Originally Posted by It's Just Eric

Yeh, my black car would overhea mysteriously...Only in toms River, NJ. Funny thing, my old red car felt the same way about that town....I think it's my pwr radiator..I swapped it from the red car to the black

Anyhow, yeah, I have a similar overheating issue. Seems if Im on a long highway trip, it'll run 3/4th hot. I turn on the heat to help vent some hot engine air out....Now, this was odd. With the temp at 85, the air coming out wasnt hot...at all. Then suddenly, the heat kicked in and the engine temp drpped immidiatly.

I also seem to be loosing some coolant, but it's likely just evaporating due to running hot. I did my thermostat a while back, which seemed to help, untill I had to drive through toms river to go to the shore meet

Anyhow, I have two guesses as to whats going on. A) a pratcing witch doctor at the pwr factory has a vendtta against NJ, or B) mabey I have a heater core clog? radiator has a rats nest in it?

[It's Just Eric]

Yeah, when I made the post I completely forgot about ol leakytop....Silly me

[Nomake Wan]

Reviving this thread since I have new information.

The system dried itself again, about two days ago. I noticed it overheating just slightly while doing a tour up a canyon road. I was not pushing the car at all, but it seemed that merely going uphill on that sort of grade was enough to push the needle up above halfway. So I absolutely babied it home, keeping the revs as low as possible, then putting her in the driveway to cool off.

When I checked it the next day (yesterday) it was empty. Well maybe not, since I can't see deep into the radiator, but from what you can see from the radiator cap it was dry as a bone, and the overflow tank was likewise empty. So let's see... I refilled on September 13th, I noticed strange overheating on the 18th of October. So in about a month it lost coolant again. Driven daily, usually short distances but about every other day would be driven moderate distances on the highway.

Now here's where the fun starts. I did a crapload of more tests recommended by an auto guy I know up in Torrance, and he seemed to come to the conclusion that it wasn't head gaskets either. His theory was a hose that only leaked under pressure and then not enough to be readily noticeable (pinhole), or the overflow tank had a crack in it. So I refilled the radiator (cold), filled the overflow tank, then drove out to meet him and go driving in the canyons again.

This time I went uphill pushing it more, keeping the stick in 2 and standing on the pedal whenever possible. When we had nearly reached the top of the hill, I noticed my temp gauge creeping up again. So I slowed back down, then pulled off and popped the hood.

Coolant allllll over the driver's fender well. After some inspection with a flashlight it seemed to be coming from the overflow tank, so we concluded that the tank needed to be replaced and called it done. Cool. Oh, and I don't know how important it is, but I should note that there were audiable bubbling sounds from the overflow tank and steam out the cap.

Except then I came home and started searching around the forums about this sort of thing, and stumbled onto something that absolutely made my heart sink.

http://www.subaru-svx.net/forum/showthread.php?t=28732

Pushing it hard in 2? Check. ECUtune? Check. Coolant all over fender area seeming to come from overflow? Check and check. No hose clamp on the overflow tank connector? Check.

Crap.

Back to square one. Now it is entirely possible that I just didn't refill it correctly and air got into the system. I went for quick on this (fill radiator, fill overflow, start car and go). Which could possibly explain why it began to overheat again.

But that doesn't solve the mystery of the missing coolant. This is the first time I've noticed leaking coolant anywhere, and was because I pushed the car harder than I ever push the car without knowing that the hose to the overflow would leak. Or that seems to be the generally accepted explanation for coolant all over the driver's fender well coming from the overflow after very hard driving.

On to the mysterious disappearing coolant. Still no exhaust vapor, still no milky oil, coolant looks fine (haven't done a proper CO test yet, will do that Monday).

So please reiterate some tests I can do to test for both headgasket failure and a failure in a part of the cooling system (radiator can't shed heat, water pump beginning to fail, etc). Since I have read a little, I will introduce as much information as I can now.

-I do have a replacement thermostat at the ready, but the engine comes up to operating temperature and maintains it without issue (under normal conditions). I have been in bumper-to-bumper traffic for hours with no issues.

-Specifically, what should I be looking for with the radiator cap off? Is there anything I should be able to see/do while the car is cold or do things happen only once the car is up to operating temperature?

============

That's all I can think of right now. I hope that the massive amount of information I've provided can be interpreted. If not then by all means ask me questions to clarify. I would love to see these problems go away.

[Hocrest]

Another hose to check that was brittle as bakalite on mine... under the intake manifold, just in front of the coolant temp sensors is a ~4" hose. Maybe pack some rags around it to hold the coolant and take it for a quick spirited drive. If you need to replace it, you can get to it with some extra long needle nose pliars without removing the manifold.

I hate to tell you, but your lack of normal HG syptoms sounds just like my HG leak. The only way to diagnose it was to eliminate all other possibilities. It ended up that the leak was from the water passage to the exterior. It was shooting out between the oil pan and the exhaust manifold, burning away as soon as it escaped.

[Nomake Wan]

Originally Posted by Hocrest

I hate to tell you, but your lack of normal HG syptoms sounds just like my HG leak. The only way to diagnose it was to eliminate all other possibilities. It ended up that the leak was from the water passage to the exterior. It was shooting out between the oil pan and the exhaust manifold, burning away as soon as it escaped.

Any way to see this from under the car? You said this earlier and I'd love to eliminate that possibility. I'm not entirely familiar with the engine layout, so I'm not sure where the oil pan is.

[longassname]

I recomend you put the front of your car up on jack stands and run it until it gets hot and you find the leak. If it won't overheat at idle full of coolant that is at least a good sign. From that point to get it hotter and look for a leak that only occurs at higher pressure just unplug a fan.

If there is an external leak you should find it that way. If there isn't then you probably have a bad head gasket. Since you are not in the financial place to fix that right, if you do have a bad head gasket, get a bottle of blue devil a new factory thermostat and 2 new factory thermostat gaskets. Blue devil is a clear blue liquid. It does not have any bits and pieces of stuff in it. It DOES work. For it to work you need to drain your coolant. Drain the radiator, remove your thermostat and cut the operating parts out of it (it's only held together by some bent tabs), reinstall the thermostat, fill the system with water, disconnect the top radiator hose from the radiator, and run the engine while keeping up with adding water to the radiator with a hose as best as you can (obviously be prepared to make a mess). Then reattach your raditor hose and fill with water and the bottle of blue devil. Drive it around and get it good and hot. After a couple days drain it and install the new thermostat and coolant. (remember actually follow my directions--it won't work with coolant; it has to be in water; it will glue the thermostat closed if you leave it in). Blue devil is about $40 a bottle but it DOES work.

[nextse7en]

This very issue vexed the hell out of me for quite some time, here is what I found.

It turns out my thermostat was sticking, and that would allow the car to get very hot, at some point the extreme pressure of overheating coolant ruptured one of the O gaskets under the water manifold, which would allow the coolant to escape in the form of steam.

A stuck thermostat is a bugger to diagnose. Especially if it is intermittent.


The next time it overheats, pop the hood, and look under the intake spider on the passenger side. Do you see steam?


-Patrick

[SVXdc]

Nomake Wan- Have you ever replaced the water pump?

Either way, crawl under the car and look for any signs of coolant/rust residue that's been dripping out of the weep holes (you won't be able to see the latter, but the trail will fall down to the bottom of the pump).

See pictures of mine in this thread: Water pump leaking? The residue also collected on the side of the oil pan and bottom of the dipstick tube.

I probably could have saved my radiator if I had noticed sooner.