2000 forester overheats under load

[idosubaru]

2000 Forester, auto, 148,000 miles picked up for a friend. Bought it sight unseen don't know much about the car.

 

I bought the car needing a rear wheel bearing and check engine light was on - Oxygen sensor.

 

Head gaskets were replaced very recently, appear to be Subaru, and the heads are all shiny - so i assume they were milled.

 

Driven it some around town and idled forever and holds steady all the time. When driving under load - heavy spirited driving, or up a long steep grade - the temperature rises and will go all the way up. Probably now that it's 90+ outside it's beginning to show. Very predictable, does the same exact thing every time. Turning on the heat helps.

 

Crap headgasket job?

Radiator clogged? p/s hose feels hot, though i don't know how hot.

 

Can i test radiator hose temps, I have a temp gun.

[The Dude]

Whatever you do, stop overheating the engine, especially "all the way up". Although the engine may have been trashed by now, anyway.

 

Go through all the usual diagnostic procedures because it could be a bad radiator cap, clogged radiator, bad radiator fans, or bad water pump. But my money is on blown headgaskets. Why do you think that genuine Subaru headgaskets were used for the repair?

[idosubaru]

Go through all the usual diagnostic procedures

i'm looking for suggestions on what those might be. probably should check for an aftermarket tstat but i'm doubtful a cap or tstat would be this predictable. i'm thinking it's internal - heads or block but would like to rule out a clogged radiator - is there a way to test that? they probably never added the subaru goop.

 

Go through all the usual diagnostic procedures because it could be a bad radiator cap, clogged radiator, bad radiator fans, or bad water pump.

thanks, i forgot to mention both fans come on and the water pump was replaced.

 

Whatever you do, stop overheating the engine, especially "all the way up". Although the engine may have been trashed by now, anyway

not interested in a headgasket/engine lashing! most folks here know that. the point isn't that i drove it like that. i wanted to make the point that it consistently rises, not just runs hotter than normal.

 

Why do you think that genuine Subaru headgaskets were used for the repair?

because i can see the external ridges and i've lost count of how many head gaskets i've replaced, so i'm fairly comfortable with this stuff.

[davebugs]

GG,

 

This is why I always have the radiator flushed and pressure tested when I get the heads done.

 

Probably been a lot of miracle cures run through this before they did the HG's.

 

I'd check the t-stat, perhaps a generic WP? and have the rad flushed/checked myself.

 

I have limited water at the garage and support my local radiator shop (they are disapperaing you know) and let them handle it.

 

 

 

That's a SOHC that typically leaks externally. If it looks like Suby HG's I'd look elsewhere first.

[idosubaru]

GG,

This is why I always have the radiator flushed and pressure tested when I get the heads done.

have you seen bad Soob radiators? never seen one yet, except rotted, external issues. it was hard for me to consider that on a 2000, but it guess it's over a decade old now.

 

thanks for the heads up. i like local jokers too, but the radiator guy is terribly inconvenient from work/home. maybe the guy i got this car for can run it over there.

[edrach]

My experience has been that a Subaru that doesn't overheat in normal driving, but runs hotter the faster or harder it's driven points to a radiator that needs replacing. With 148K on it, I wouldn't waste time/money backflushing or anything else. Find a new radiator and install it.

[edrach]

have you seen bad Soob radiators?

Yes, numerous times over the years on many Soobs.

 

Only exception was once when someone mis-wired the fan on an old GL and it was running in reverse and fighting the normal air flow through the radiator.

[The Dude]

Gary, it's a little early here in SC, and I responded to your post without noticing who had posted it. I usually only give advice to "noobs" with under 10,000 posts.

[idosubaru]

Gary, it's a little early here in SC, and I responded to your post without noticing who had posted it. I usually only give advice to "noobs" with under 10,000 posts.

no sweat, that's why the LOL's were there. how dare you only give advice to noobs! i hadn't mentioned some things you brought up and driving in H is way-bad, so understood and thanks for posting.

 

looks like i'm going to try and test the rad and check for an aftermarket Tstat......but i've done a lot EJ25's it's hard for me not to think HG, HG, HG, HG.....

Edited July 6, 2010 by grossgary

[Petersubaru]

more of guess here, but then again it has been also my experience..if both fans come on (A/C turned off).. this would point to a thermostat problem..over heating could be a small leak (hardly noticeable) allowing air into the system...hold off on the rad until you are completely sure...keep in mind that a pressure test may or may not find the problem..it really depends on how large the problem is ...

[hankosolder2]

GG,

 

Perhaps the PO kept topping up with water prior to having the HGs done and that accelerated corrosion in the radiator? It sure sounds like a bad radiator to me, and even if it isn't, why not eliminate it as a potential factor? I'm usually not one to throw parts at a problem, but having a fresh rad in a 10 year old car is good for peace of mind anyway.

 

Nathan

[idosubaru]

Note - when driven at night it runs less hot, generally stays normal except when climbing. When driven during the day (currently having a heat wave of 96 in our area) it runs hotter and not as much near the normal mark.

[GeneralDisorder]

Yeah - the radiator could easily be partly clogged.

 

Just check for cold spots on the radiator. A laser temp gun is helpful.

 

Too much of the Holts stop-leak that Subaru sells can clog radiators and heater cores. They say you can use two bottles at once but any more and it could cause problems.

 

I just replaced a radiator on a '97 L - same deal. They probably tried some block sealer and clogged the radiator.

 

GD

[idosubaru]

I just replaced a radiator on a '97 L - same deal. They probably tried some block sealer and clogged the radiator.

do you know what symptoms it had or how did you know? i know you're not one to just throw parts at it. i have a temp gun so that's an option.

[GeneralDisorder]

I reached down between the fan blades and felt the radiator surface (unplug the fan) - it was hot along the top edge and at the inlet/outlet but cold/lukewarm over much of the center of the radiator - this was with the engine starting to climb above half.

 

Replacement radiator is hot all over. Still has bad head gaskets but takes a lot longer to overheat . They probably just made it worse trying to fix the problem with a "repair in a bottle". etc.

 

People talk about having them boiled out, etc - but I get them for right around $100 and I've seen too many of these plastic tank units crack and leak when they get old. They are throw-away radiators IMO.

 

GD

Edited July 7, 2010 by GeneralDisorder

[idosubaru]

had an aftermarket tstat in it, so i replaced that this morning. forgot the key so couldn't test it and hit it with the temp gun. i doubt that's the issue, but quick and easy.

[idosubaru]

T-stat didn't solve it. Temp drops drastically when i turn car off for a few seconds and drift/coast, then turn it back on. I'm thinking head gasket but i'll look into the radiator.

[Qman]

Gary, quit throwing parts at it. Many people have told you the problem and solution. Don't be one of those people. The ones that ask a question they do not know the answer for then question all the answers.

 

REPLACE THE RADIATOR!

[idosubaru]

if it was my car that'd be cool as i don't care about the money and plan on having them awhile. but it's not. be nice to diagnose the radiator, it could be internal leakage/headgasket in which case a radiator is equally throwing parts at it.

 

my last 5 words were:

i'll look into the radiator.

i don't consider swapping a thermostat as "throwing parts at it".

 

a couple years ago my daily driver xt6 was overheating (thread here http://subaruxt.com/forum/viewtopic.php?f=1&t=7267&p=68665&hilit=running#p68665) and i replaced the radiator and that wasn't the issue. trying to learn something here to diagnose. GD helped out just a couple posts ago.

 

i'm sorry it's taking a few days, i'm also helping friends for free with a seized Ford Escape caliper, wrecked 2010 Kia, and exhaust leaking legacy. The Ford and Kia I'll finish today hopefully.

[Qman]

if it was my car that'd be cool as i don't care about the money and plan on having them awhile. but it's not. be nice to diagnose the radiator, it could be internal leakage/headgasket in which case a radiator is equally throwing parts at it.

 

my last 5 words were: i don't consider swapping a thermostat as "throwing parts at it".

 

a couple years ago my daily driver xt6 was overheating (thread here http://subaruxt.com/forum/viewtopic.php?f=1&t=7267&p=68665&hilit=running#p68665) and i replaced the radiator and that wasn't the issue. trying to learn something here to diagnose. GD helped out just a couple posts ago.

 

i'm sorry it's taking a few days, i'm also helping friends for free with a seized Ford Escape caliper, wrecked 2010 Kia, and exhaust leaking legacy. The Ford and Kia I'll finish today hopefully.

 

First, your hatred for the 2.5 is showing. All the symptoms are classic radiator. Period. You already said the gaskets look to have been done. If they were bad or badly done they would be either leaking externally or internally which would result in steam from the exhaust.

 

Several people told you the radiator. Yet, you replaced the thermostat. The thermostat is inexpensive. But, had you taken the advice given you would be done...

[sajtman]

For anyone that comes here-frustrated after trying many things and using Google a lot-and wondered what the outcome of this thread was, I can't exactly say.

 

But I can say following Qman's straightforward recommendation with a new radiator fixed all of the overheating problems I had for my '02 Forester that were showing up in conditions like here - long extended highway runs, more in the day than at night, uphill for a while, fine for around the city.

[edrach]

Gary, quit throwing parts at it. Many people have told you the problem and solution. Don't be one of those people. The ones that ask a question they do not know the answer for then question all the answers.

 

REPLACE THE RADIATOR!

Are you sure? Maybe he should just backflush it first.:rolleyes::rolleyes:

 

Sorry, I couldn't resist. Funny, it's been two months now and we still don't know what really fixed it.

[idosubaru]

one of the worst cars i've worked on (not including rust issues ). in this order it got a new radiator, a new block/headgaskets, and a different intake manifold - and has been fine since then.

 

i seem to recall thinking the original motor had non-OEM headgaskets on it when i pulled it and the heads off. probably laying in my garage still with the original block and bits, maybe i'll run across them someday and try to check.