intermittant overheating issue...not all the time..help!

[wstauffer]

Well, I have a subaru legacy awd sedan with a 2.2 liter single overhead cam engine (non-turbo) with 220,000 miles. After replacing the leaking waterpump with a "good" used one, I noticed that the pump was still leaking...looked like the replacement was bad, as well. I was told to "buy some time" and put a chemical in the radiator that is used to stop head gasket problems...and was given yet another bottle. Still, I had to top off the radiator after about 3 days of driving (you could smell the antifreeze and see small drips). After about 3 months or "hobbling" like this, the leak stopped, and stopped for over 4 months now. The theory had been that perhaps the replacement waterpump sat for a while and the seal got hard, but then loosened-up. Anyway, a new problem started...occasional heating - up. It only does it on very hot days, or when going up hill for a while (I can force it to happen if I drive it in second gear for a while). After letting it cool down for about 15 minutes, it starts-up and appears fine for several days...then it will happen again. It seems to do it most when you drive it for a few miles, shut it off, then start it up again (happens almost every time I go to the baby sitters to get the kids). Driving it at highway speed seems to cure the problem (increased airflow?) because if the car is sitting still and reving (increased water flow) the engine will heat. The fans are both working. Could the chemical added to the radiator have clogged up the radiator some? I have had older subarus (ahhhh, the loyale era....ick!) and the signs of heating up were much more obvious...typcially busted heads, white smoke-screen and that sweet smell, extreme pressure in radiator cap if cold and started up then cap removed, etc. The newer style legacys seem to be a little trickier. Any suggestions would be great. Head gaskets? So far, I am not convinced yet...whet should I look for? Thanks for your help in this.

[wstauffer]

Just as an update, I took out the suby tonight (3:00AM) and it was about 75 degrees out...could not GET that thing to overheat...even drove it in low geat with AC on...wouldn't rise even to the half-way point (typically resides just below half way normally). After reading some similar posts to mine, I checked the antifreeze in the radiator...pure green, but with some globby white stuff on the underside of the radiator cap and floating in the radiator. Resevoir, clean green with no clumps. Oil, (added a little), drove some more, checked it, and it was "clear black..." a little dirst, but no signs of milkiness. Lastly, revved it up, and absolutely no bubbles in the resevoir after it was warmed up. The suby is a 1997 (I know this is an older model post, but the engines are of course essentially the same). Again, both fan cycle even when it heats, and it does heat some about every day since the temp out has been scorching lately here in PA. Hope this helps! Thanks, Bill

[Project_Legacy]

so you're saying that your temp isnt rising to normal operating temps? maybe your thermostat is stuck open. sounds plausable right? thats what i am getting from your second post anyway... other than that i dont know.

[wstauffer]

No, no....it rises to whewre all my subies have risen to...just less than half-way. I guess I am saying that it only heats up when it is really hot outside, usually going up hill (a load) with the ac on. It will go towards the peg, I will shut it down, wait awhile, then it is usually fine for a while.

[Kelly]

I think I'd start with draining the cooling system. Im not sure how the Stop Leak stuff works, but I can guess. Id pull off the thermostat housing, and see if big chunks of gelatinus goo come out.

[Project_Legacy]

ooo. my bad. my turbo is doing the same thing sort of. it'll rise to normal (a little less than half way) then when i push it a little it'll start getting hotter and hotter especially when its hot outside. same symptoms your having huh?

[wstauffer]

yeah, sounds similar. Now, today it was hot, so with the AC on, and driving around town, it began to climb. Turn AC off and sit at idle in park, comes back down. Drove it highway speed with the AC on, not a problem. Sitting still, rev the engine to about 3000 rpm with AC off and in park, stays high but does not seem to climb higher.

I know people will think head gaskets, and I do not want to be in denial, but none of the other signs are there of head gaskets, like mixing of the fluids, excess pressure, bubling, etc. I ordered an aftermarket radiator off ebay for $125 shipped (give or take), and I will probably check out the thermostat too. I think those are cheap investments to see how it goes (I will do the work myself). I also have a new waterpump that I have had for a while and never put on, although I do not think that could be it. If this does not do it, I would have to lean toward the head gaskets I believe. My dad has some dye and a blacklight...might give that a try to see if there is any mixing. Again, it is not like the older beasts...when those MF's heated up, they spewed, cracked heads, heated sky high, blew the ploom of white smoke, pinged like all heck, etc. It seems that the new subies are a little more "mysterious."

I am still listening to suggestions, and will keep you all posted on the outcome.

thanks, Bill

[professor]

sounds stupid but make sure your fans are blowing the correct direction

did you get the car with a leaking waterpump? if so then maybe quite a few cans of stop-leak were used, which tends to block the thermostat or radiator core itself

[wstauffer]

Not stupid...would make sense, you know...and to be honest, I will have to check to be absolutely sure. I did not get it with a leaking waterpump, but who is to say that it didnt't leak before, was stopped witht he stop leak, then started leaking again. Certainly food for thought...and I will check tomorrow. Thank you!

[professor]

I must admit that a few cars have rolled off the professor's lot with a can or two of Barr's Leaks used.

if you haven't replaced the thermostat now would be a good time, they are cheap and usually get slow with age anyway, and you can look at the passages to see how gunked. I'd also back-flush the radiator at that time, and see what comes out

[wstauffer]

Weell, folks...not head gaskets! yee-haw! Turns out, I ordered a radiator thinking that a few cans of suby stop-leak may have clogged the radiator. When the radiator arrived, I pulled the thermostat to drain it...therm looked great (no gunk). I had previously replaced it with a new one about a week ago. Anyway, when I pulled the radiator out, the "FINS" were clogged! I was confident I found the problem! LOTS of dirt, mud, grime, etc. in the radiator fins. I went ahead and installed the Koyo radiator I bought on ebay for $85 plus shipping, filled her up gingerly with antifreeze (long process) and that did it! The next day it was almost 100 degrees out...went up a large grade with ac on...absolutely no problems...way less than half-way...where they should be. Now that I look back, the AC was sporatic...kept cycling on and off, even though pressure levels initially were okay...it wasn't getting any cooling either! Strangely, the radiator was clogged, but no the AC condensor...

Anyway, hope that helps some out there. The Koyo fit perfectly and is holding water...great price!

Later, Bill

[Project_Legacy]

its an exact fit too?? i mite just do that.

[wstauffer]

YES! the Koya fit EXACTLY! Please try...cheap insurance, and easy do-it-yourseld in the driveway with reg. tools.