legacycentral bbs

I have a 94 Legacy that is having slight overheating when I turn on heater full blast. I'm in Hawaii, the previous owner's mechanic took out the thermostat (which is common here). So, I replaced the lower radiator hose and smaller hose above thermostat housing, flushed and burped the cooling system today after this same thing happened the other night (but needle went way higher). It runs normal (needle just below midway) until I turn on the heater. Before I did all that, it went way up, but tonight up just a little bit, then came down, fluctuating a little. Is this a possible Head Gasket? There is no oil in coolant or vice-versa. No smoke. There is a wee bit of oil seepage down below, around engine block, looking like a very slow leak. Any ideas? I'm stumped.

Welcome to the BBS.

You need to put the thermostat back in. The engines do not like having the t-stats removed.

Secondly, the thermostat needs to be a Subaru thermostat. Aftermarket parts store thermostats do not work in these engines and will cause issues with overheating or just inconsistent engine temperatures.

There may be other issues, possibly a head gasket, but until you rule out the thermostat, I wouldn't go jumping the gun on the head gaskets.

Thanks Josh. So, the thermostat I got and then took back (after asking several local mechanics about if I needed a thermostat here on Maui) was OEM from Napa. I could have gotten a Tama OEM which was not in stock and about $21.
Why don't the engines not like constant cooling if it's in a warm tropical climate?

Did the thermostat's you had look like this?

http://main.experiencetherave.com/subar ... P_4799.JPG

The Subaru thermostats are deeper and have a different response curve to temperature changes compared to most aftermarket thermostats. The aftermarket thermostats will tend to respond more quickly to temperature changes where the stock thermostat won't. So the aftermarket thermostats will cause temperature fluctuations.

As to your question about not running a thermostat, the main issue is you'll over cool the coolant if you drive at highway speeds for any extended amount of time, and/or run the air conditioner, which kicks the AC fans on.

The temperature in Houston in the summer is HOT, and probably hotter than Hawaii. People don't remove the thermostats here. My personal opinion is that the belief of removing the thermostat is one of those old-school engine tricks that really doesn't apply to the newer engines.

The mechanics there may be very competent mechanics, but I can say with pretty confidence that you should be running a thermostat in your Subaru. As mentioned, there may be other issues, possibly a headgasket, but why start there, when you can get a thermostat for around $20.

I would only recommend using a Subaru thermostat. The part # is listed in the picture above, and you can order one from one of the online Subaru dealers if the local Subaru dealer wants too much. The Subaru thermostats go for around $20....give or take $5 or so. Check out www.subaruparts.com www.1stsubaruparts.com www.subarugenuineparts.com

If you don't want to get a Subaru one, Stant supposedly makes one that supposedly has the same characteristics as the Subaru thermostat. I have not tried it, but here's the info on that one.

http://bbs.legacycentral.org/viewtopic.php?f=5&t=48642