Self Healing Head gasket??

You could have a sticking/bad thermostat and/or a bad radiator cap. a plugged o'flow bottle tube, a crack in the radiator tank etc. are other less likely possibilities. Could the residue you saw have been some stop-leak type subsatnce the previous owner had used?

I dunno

Carl

Call your subie dealer, give them your VIN and ask if the coolant conditioner service has been performed.

Alternatively, go register on my.subaru.com, and it will give you all that info.

troot wrote:

From my experience HG leaks do not heal themselves. I agree with Carl, that a sticking thermostat could be the culprit. The top radiator seal has also been suspect as has a bad radiator cap or cap seal. As mentioned the "cooling system conditioner" is a must and will usually take car of coolant weeping.

Thanks for the input! The thermostat is on the short list of possibles. The cap and over flow bottle are in very good shape and seem to be fine. When the system went south, I had a sudden loss of coolant, not a weeping leak. Not seeing any further leaking. My guess is that the system blew out the coolant via the overflow. I wish I had paid more attention, but I was stressed about over heating the engine. I don't remember the over flow cap being displaced or the rad cap being loose, just losts of coolant every where. It wouldn't hurt my feelings one bit to have to replace the thermo instead of the head gaskets. Regarding the coolant conditioner. When I cleaned the over flow bottle I got less than a nickle's worth of material . It was black and had a hard , but rubbery feel. However, I thought that the conditioner was used to address the HG problems in the later ('00 +) series of the 2.5 motors, mine is a '99

BTW the Soob dealer reports that they only do about 3-4 HG jobs a year ??? This is a fairly large dealership in Newport News VA. Maybe folks go else where??

Dave C

Call the Subaru dealer and have them check if the service was done. Actually, first look for a sticker in the engine bay, on the radiator support beam, that would say "coolant conditioner... blah blah".. the sticker might be all worn out (it is on my car) but you should still be able to make it out.

When the HG was bad > Thanks for the input! The thermostat is on the short list of

No, and yes.

I had a 2.5L straight 4 Cherokee that intermittently showed sudden overheating, then would run fine for 2-3 months without a hitch, over the better part of a year. After one "hot" session, I found the mocha-latte deposit in the oil fill cap. That's my experience, and I'm stickin' to it.

if there's black gunk in the overflow its oil...keep your eye on the heat gauge ....i've read many reports which stated the HD lasted for a while...keep the rpms down and it may keep goin..

only 4 hd's a year?....don't believe 'em

thermostats do go...but the black stuff is a concern

Agreed. A bad thermostat won't cause there to be oil in your coolant, and 'mocha latte' in your oil pan...

Black gunk in the overflow is also caused by someone using water-wetter in the coolant.

And I think he said black - not tan or brown, and a 'nickel's worth',no mention of a 'film'. Heck, that could be trash from factory assembly.

I dunno

Carl