What's the reasoning behind my car running hot when I use AC? Is it just because there's that much more pull on the engine, or is there some other connection that I can do something about? It seems to me that my car runs a little hot at highway speeds anyways, but it runs even hotter when I use AC.

The AC evap core is in front of the radiator. Replacing your radiator will help to cool it more effectively. Check the thermostat as well.

 

GD

Thanks, I may see if I can find a radiator cheap, I know mine's seen better days.

Both EA81 Subies I have owned had cooling system issues that were solved by removing the radiator and taking it to Reynold's Radiators (in Missoula) to have them ROD out, patch it up, and straighten finns on the original radiators. I spent ~$65 on each & it worked like magic.

as a temporary measure, you could spray concentrated degreaser (like Simple Green) onto both the radiator and the AC condenser (when totally cold) let it soak, and spray it out with a fairly high pressure garden hose. If you don't want to go to the length of removing the radiator to do this, I would recommend blasting it out from engine side towards the front..

 

Lots of road grime can accumulate on those coils, insulating them from the air. Blasting from inside the engine bay has the effect of rinsing a reusable AC filter from the correct side... any particle stuck on the front by definition has a hard time passing through the coil.

 

I don't know much much it will help, but I know that the coils on my window AC unit get dirty enough to rob all efficiency (not INCREDIBLY dirty, either) after a few months; between cigarette smoke and cat hair, if I don't take the thing out and clean it it cannot beat the summertime florida heat/humidity.

Great, thanks guys. So...if I don't want to make the drive to Missoula but I'm feeling motivated, take out the radiator and clean it off? Or be a bit lazy and spray from the back? I can handle that. Thanks.

I didn't mean that you need to go to Missoula for the work! Just source a local radiator shop in Helena.

for a radiator that you have dubbed in need of replacement, I would say taking it out is going a little too far to be worth it.. but if you feel extra motivated, your results can only be improved by taking it out. I suppose there might be a minimal risk that in removing it, you might disturb something you wouldn't have if you just cleaned it leaving it in.. but think of that as a disclaimer. I want to say "it could only be better if you took it out" but, there is always a minimal risk..

 

However, in your case, if you weren't going to take it out anyway, I dont know if I would bother taking it out just to clean it. Is it visibly that grimy? It should be fairly apparent that you need to do this, if it is going to help much. If the radiator looks pretty clean, but you want to clean it to see if it helps anyhow, I highly doubt its worth removing.

 

Its your decision to make, pulling the rad is not a big deal; I like the idea of pulling it to flush and clean it, if it is a radiator you have faith in. I recommend it to people. In your case, unless you see lots of grime, I would just do it in vehicle. I feel awkward in recommending the less thorough route; for all I know this could be 95% of your "radiator problem" right here.. but its a judgment call, really.

www.radiatorbarn.com has them for right around $115 shipped For the ea81. If yours is questionable I wouldn't bother messing with it, when it will be going out anyways.

Alright, thanks everyone. MSSLGECKO, I saw that you were in Bozeman, not Missoula, so I guess I thought you may have traveled.. Ok, I'll check it out and see if it's really dirty. I need to change some hoses anyways, so I'll drain it & flush it while I'm at it. It's an '87 EA82, btw.

hey i have the same problem with my 85 subara gl station wagon 4x4

i have 104,000 miles on it but today my tensioner pulley went on 105 east just pasts the 110 to la

dealer told me ac was a after market ad on so they cant get that pulley so you should check yours before it goes out but if it does and your alt belt is still good you can pull the back one and reinstall the other one and you on the road

Hmm....I was just reading some other threads and saw that people recommend using only OEM thermostats? I just bought an aftermarket one..should I return it and go with OEM? Also, if you're feeling like humoring me and responding...I've never replaced the thermostat in a Subaru before and asking is easier than looking in the manual...Where's the thermostat on this car? (87 GL Wagon, Carbed) Thanks! I'm changing the fluid and upper & lower hoses, and was going to do the thermostat..but if I should only use OEM it may have to wait.

Its on the intake manifold. Where the upper radiator hose connects. The housing is held on with 2 12mm bolts IIRC.

Thanks