Outback Question Overheating

[Cynic]

Since you guys and gals have answers to so many of life's questions, a friend asked me to ask...her outback started over-heating. When they checked, the overfill tank for the rad was dry, so they filled it up, drove, checked it and it was dry again. Took it in to mechanic, no rad leak and pressure was checked and was fine. They are being told a master cylinder is probably the problem. Anything else they should be checking? She's 8 months pregnant and needs her car back. As of now, its just sitting in the driveway. Thanks for any help

[RojoRocket]

What does a master cylinder have to do with overheating and disappearing coolant?

From personal experience with a number of Legacy engine problems on 2.2 and 2.5L engines, it's most likely a head gasket problem. You didn't mention the year, which might make a difference whether it's an internal or external leak. Mech should check the coolant for signs of combustion traces, and bubbles in the overflow when running after warmup. This can be done rather easily, result of internal leak forcing coolant out the overflow. Usually on earlier, 97-99 models. Later versions of the motor were more prone to external leaks, easily detected by, well, puddles, and signs of leakage. The later, improved multilayer gaskets are much less prone to failure after replacement. This usually includes checking mating surfaces for warpage caused by multilpe instances of overheating (heads and block). This is a serious issue and not to be dealt with by just refilling with coolant. Been there, done that. Good luck to your friend!

Glenn

[subarufamily]

i agree with above , what does a brake part have to do with a cooling part ? the motor probably has a bad head gasket which allows for the burn off of antifreeze does it make white smoke at any time ? or smell bad like sweet smell when running or idling ? there would be a great help to know what year and miles manual or auto transmission?

[NiftySVX]

Could be as simple as a low coolant condition causing an air pocket in the block. I would try filling the upper radiatior hose and then refilling the radiator. Just to make sure.

[ensteele]

If it is the 2.2L engine, they were much more prone to head gasket leaks than the 2.5L engines. The 1996 MY is bad news and are very likely to over heat. They had the 2.2L engines. The 1997 and later are much better because of the 2.5L engines. A year of the car would be a big help.

[RojoRocket]

Originally Posted by ensteele

If it is the 2.2L engine, they were much more prone to head gasket leaks than the 2.5L engines. The 1996 MY is bad news and are very likely to over heat. They had the 2.2L engines. The 1997 and later are much better because of the 2.5L engines. A year of the car would be a big help.

Earl, there are a few folks here who might disagree with you.
http://forums.nasioc.com/forums/showthread.php?t=184026

I've experienced HG failure with both motors, so can't really debate the finer points. Wasn't a dedicated net junky when we had the '91, but this seems a very common failing in the 2.5L as well. Nifty has a good point, but if experiencing a "low coolant" condition, how did all that coolant escape?

Glenn

[Cynic]

I've send off an email asking her the year, etc. They just bought the car, and a week later this happened. Her husband is up north with the Coast Guard, and she'd like to sort it out before he gets back. Thanks for all your help. I'll post the info later today.
Cyn

[ensteele]

Originally Posted by RojoRocket

Earl, there are a few folks here who might disagree with you.
http://forums.nasioc.com/forums/showthread.php?t=184026

I've experienced HG failure with both motors, so can't really debate the finer points. Wasn't a dedicated net junky when we had the '91, but this seems a very common failing in the 2.5L as well. Nifty has a good point, but if experiencing a "low coolant" condition, how did all that coolant escape?

Glenn

I read that thread, and it didn't change my mind. It seems to say the same thing.

[RojoRocket]

Sorry Earl, didn't mean to confuse the issue.
It appears our opposed motors are prone to HG failure regardless of size, model or level of maintenance. Been through it with the SVX too. Most vocal group appears to be the 2.5 crowd though. Shrugs. I'm convinced it should be on every Subie owner's list of inevitable expenses, and should probably be included on the scheduled maintenance tables. At least then we would be able to schedule it.

Glenn

[Cynic]

The car is a '97 Legacy Outback; 2.5L auto; new rad and sencor cap (don't know if I got that right). I sent her the link to this thread, so she and hubby can read your answers and disscussions before talking to mechanic. I love that he's up in the Arctic on a boat and has access to the world thru computers. Its a wonderful world.

They both send their thanks.

[RojoRocket]

Thanks for more detail Cyn.
The 97 OB should have the same radiator I have in my 98 GT. When refilling with coolant the black plastic Phillips head plug on top far left (passenger side) of the radiator should be removed first. It acts as a bleeder for the air rising out of the radiator, as well as the upper radiator hose. When coolant comes up out of the hole the rad "should" be full, and the plug replaced. If the car is sitting level, engine off, just remove it, and the cap, fill to overflowing, replace both, fill return/overflow tank to its upper mark and go.
If this still results in overheating then look for aforementioned bubbles rising in the overflow, as well as the radiator, sure signs of a blown Head gasket. Any reputable mechanic can test the coolant for chemical signs of exhaust gases, and another sign is black, sooty residue around the neck of the radiator and return tank. If this is the case your friends are in for a major expense. It's nearly impossible to know which side is blown, necessitating removal and renewal of the HG's on both side. If it's any consolation, use of the latest multilayer replacement gasket from Subaru should prevent any recurrence.

Glenn