Need help - Legacy is Overheating

[bunnymama]

First post, it's a big one.

 

My 96 Legacy wagon has been overheating. No bubbles in the resevoir and the large hose on the passenger side of the radiator is hot when I check it. It doesn't seem to fit the symptoms of the dreaded head gasket problem. I am stumpted. Here's the story:

 

Tuesday we were commuting into work, after ~20 miles of pure highway driving the temp gauge started to climb and quickly reached the upper limits of the gauge. I pulled over and shut it down. There was a small amount of steam coming from under the hood. I left the key in so the fans would run to help cool the engine and then popped the hood. Anti freeze had sprayed inside the engine compartment on the driver side. I checked the resevoir, it was more or less full. No bubbles. Turned the vent cap a little and thought better of it when liquid hissed at me a bit. We let it cool and got got back on the road. While waiting (stopped) for a chance to turn around and head home the needle started climbing again. As soon as we got moving again it began to drop and probably hit the halfway mark within 200 yards of driving. Gauge remained just below halfway almost the whole way home.

 

We got of on an exit ramp, stopped at a stop sign for about 5 seconds, and were on our way. Needle began climbing. Within a mile it hit the bottom of the "H" I pulled over again. No steam, Fans turning, check resevoir - half full, no bubbles. Here's the odd part. I didn't feel a lot of heat under the hood. Placed my hand on the engine (manifold?) not hot at all??? Let the temp gauge hit halfway and head home again.

 

After about 2-3 miles were on "H" again. Pull over repeat steps. Resevoir is nearly empty. Engine still feels cool. Gauge drops we are moving again.

 

Repeat above steps after a half mile or so.

 

We are home. Resevoir is empty. Hose is hot. Engine is only warm. I crack the radiator vent cap, no spray. I remove it. I open the radiator cap with a towel. No spray. I add about 32 oz of water before coolant percolates out of the open vent.

 

Engine cools for abaout and hour and a half and it's of to the mechanic. 4 miles no overheating. He uses it as his daily driver the rest of the week, no overheating. He replaces the thermostat as a Hail Mary. I take it home tonight (Friday.) No problems on the way home.

 

2 hours later I am running to the store. Less than 2 miles and I'm overheating. Pull over, pop hood. Fans turning. Hose hot. Engine hot. No coolant spray. Resevoir is almost full.

 

I stop three more times before I make it home.

 

Any ideas? I am lost.

[swami2806]

Start simple: When was the last time you changed coolant, cap?? Second, did you have the A/C on initially? There are two 10 amp fuses for the fans on those. One is the regular fan and the other is your A/C fan. The A/C one might have blown and the load caused the overheat. Also, there may not necessaraly be obvious bubbles if it's a head gasket. Call around and ask garages what they charge to analyze your collant. There is this sensor thing that can pick up engine gasses in aintifreeze just by opening your radiator. I'd say to have a pressure test done too, but we already know the answer to that. Hope this helps.

[bunnymama]

Opps, let me jump in the way back machine. It overheated about two months ago. At that time I replaced the radiator cap. No overheating problems until the recent round.

 

However I just got a sick feeling. Sometime after I replaced the cap, I got an oil change. They said my coolant tested "not safe" I had them change it out. Could coolant gases cause it to test "not safe" ?

 

I should add, I've got ~170,000 miles on it.

[lmdew]

Is the coolant being drawn back into the radiator, when the engine cools? If not you have a leak somewhere, most likely the HG. A leaking HG will force the coolant into the recovery tank, but many times will not draw it back into the engine when it cools. Check the fluid at the rad. cap when its cool and see if its full. If not find the leak, HG or otherwise. Good Luck, Larry

[Chip Hedrick]

Who did that last coolant change? Did they properly burp the engine? If not, they might have left an air pocket which lead to the recent spat of severe overheating.

[tcspeer]

Pull the radiator out and look at it. May be you just need to wash dirt out of the fins. Mine overheated a few years back and that was what was wrong with it.

[rweddy]

Is you 96 and auto with the 2.5?

If so my bet would be HG.

[bunnymama]

I'll have to check the fluid level in the morning, but I believe the coolant is being pulled back into the radiator.

 

I had a coolant change done by a Valvoline Instant Oil Change place. Did they burp it? They do them all the time, I would expect them to know how but I really don't know. Friday, when my regular mechanic (who has been super every time we used him.) changed out the thermostat, he explained to me how they hooked it up to a machine that removed all the air pockets. I assume this means he burped it.

 

Yes, 96 with the 2.5

[theotherskip]

the subarus are a bit more tricky to get all of the air out. i don't know if the quick lube place would know to open the air bleeder on the top passenger side of the radiator. air pockets would definately cause irradic temperature readings, but with the tendancy of this engine to blow head gaskets, just be aware of what to look for.

 

to get it to blow bubbles, i had to take mine out on the highway for 20+ minutes, then pull over and check the expansion tank with the engine running. i would see a steady stream of small bubbles coming from the overflow tube...

[swami2806]

Bring it to your regular mechanic and have him do the analysis thing on the coolant. If there are no gasses, ask him to "burp" the system. tcspeer also makes a good suggestion--check to see if the fins are clogged. Thanks for reminding me to look at the wife's!

[bunnymama]

We burped it today, and let it idle for ~40 minutes with no overheating. I'll take it for a lengthy drive tommorrow.

 

Fins look ok.

 

Will have it checked for coolant gases asap.

[sisu]

We had a 1990 Toyota Tersel that over heated, so we flushed the system, replaced the thermostat, and put in a new 50/50 mix. It still over heated. Went to NAPA and told them of my dilemma. They told me to go to a shop and have my catalytic converter checked. Sure enough it was the cause of the problem. I guess if it is plugged up it can cause the engine to over heat.

[bunnymama]

Sisu, your post intrigues me.

 

Took it for a drive. Overheated about 15 miles from home

 

Followed some advanced burping instructions I found in another thread. Got alot of bubbles out. Ran it for awhile at ~2000 RPM with occasional revs to 3000. Noticed steam coming up. Looked for the source. Not the radiator. It's not steam, it's exhuast. It is coming from the Y joint right in front of the front catalyst! Could it be that a catalyst blockage is causing the overheating and exhust escape?

 

My mechanics sensor for check for gases is dead so I am going to find somewhere that can check for me Monday. I'm going to have them check my catalyst also.