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Repair '91 Legacy head gasket in-car: an at-home job?

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I have a two 91 Legacys and on one the driver's side head gasket is blown. I surmise this because compression is low on both those cylinders and the temp gauge is pegged at H. However, the gauge shows oevrtemp even though the engine is not hot to the touch. I suspect exhaust gases are reaching the temp sensor on that side. engine still fires and ticks over sweetly, but is rough running when gas applied.

 

My question is can the head gasket be replaced with the engine still in the car?

 

All the online references seem to point to benching the engine before doing this. I'm mechanically inclined, and have maintained this car and fixed many of it's ills. However, I'm not equipped to remove the engine. It looks like it could be done in-situ, and I have read posts warning against over charging dealerships that insist on pulling the engine unnecessarily for this task.

 

Has anyone done this at home and can advise me ASAP before I make a decision on do it myself or sell off the Soobie? An alternative is one of those coolant additives for plugging blown head gaskets.

 

Thoughts/advice?

 

Thanks

Doing a HG really isn't that hard. Doing one in the car will make it a b****. Due to the confined space, it would probably take longer to do it that way than to pull the engine and do it on a bench. You can rent an engine hoist for cheap. Also, it's probably a lot harder to do as good of a job (getting everything spotless) if it's in the car.

 

BTW: Don't ever use cooling system stop-leaks except to get you home from the middle of nowhere. They cause more trouble than they solve and I highly highly doubt they would seal a blown HG at all.

The head gasket can be changed with the engine in the car. Space will probably be a little snug, but yes it can be done.

 

Are you aware there is a bleed screw on the passenger side of the radiator? Open that, refill the coolant and see where you temps are.

 

I'm not saying your head gasket is ok, but it sounds like you have an air pocket in there.

  • Author
The head gasket can be changed with the engine in the car. Space will probably be a little snug, but yes it can be done.

 

Are you aware there is a bleed screw on the passenger side of the radiator? Open that, refill the coolant and see where you temps are.

 

I'm not saying your head gasket is ok, but it sounds like you have an air pocket in there.

 

It's the low compression in the driver's side cylinders that leads me to believe that it's a head gasket. Could an air pocket cause that, do you think?

 

Certainly bleeding the cooling system is a much smaller job and worth a try if it will fix the issue.

 

Stephen

Here's the real test.

Open the radiator cap, put some water in til full. Run the car for a while and look for bubbles in the coolant. If they smell like exhaust, you're done. Blown headgasket. Call CCR.

I don't think that you want to tackle it in the car, not enough room.

Pull the engine and put a rebuild in. I've been there and know..

Good Luck..

  • Author
Here's the real test.

Open the radiator cap, put some water in til full. Run the car for a while and look for bubbles in the coolant. If they smell like exhaust, you're done. Blown headgasket. Call CCR.

I don't think that you want to tackle it in the car, not enough room.

Pull the engine and put a rebuild in. I've been there and know..

Good Luck..

 

Thanks Bartt. Good advice. What's "CCR"?

Colorado Component Rebuilders... They're THE place for reman Subaru engines.

 

 

http://www.ccrengines.com

 

 

However, if your engine is otherwise in good shape, I think replacing the HG's and having the heads resurfaced is all you would need to do at this point.

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