Hi,

 

My 91 Legacy Turbo has sprung a nasty little oil leak of late. Somewhere oil is leaking from the engine, either underneath or near the firewall as far as I can tell, and hits something hot and burns up. This produces a horrible petrolum smell when I'm idling at a stop since the smoke gets sucked right into the HVAC intake. I haven't had a chance to crawl around down there and get a better look yet. At my last oil change the report mentioned a "possible rear seal leak". Could this be my problem? Where is the rear seal? And how much am I looking at in parts and especially labour to get it changed?

 

Thanks for you help!

Hi,

 

This does sound like a real main seal problem. The rear main seal is an oil seal, much like the ones on the front of the engine (crank and cams) that seals the exit point of the crankshaft from the back of the engine. Just as the front seals fail, rears can too.

 

Unlike the front seals, however, replacing the rear seal requires that the transmission be removed from the engine. If you think about the way the parts are connected, the driveline has to be separated to get the thing out.

 

You don't mention whether the car is a manual or an automatic but my philosophy is to always replace the rear main anytime I need to drop the gearbox, such as for a clutch replacement. If you do have a manual transmission, you might opt to hang in there till you need a new clutch. That's a personal decision as the leak is not likely to damage anything (except your olfactory glands).

 

As for cost, think of it as the cost of labor for a clutch replacement as the main seal itself costs almost nothing. Your spelling of "labour" suggests that you are outside the US somewhere, so I can't even begin to speculate on the costs.

 

Regards,

Adnan

Thanks, very observant with the spelling I'm Canadian.

It's an auto tranny, so I won't be waiting for a clutch replacement.

I have a feeling this is going to cost me

I'm almost due for a tranny fluid change though so at least I can get both done at once, if that's any savings at all...

 

 

Hi,

 

This does sound like a real main seal problem. The rear main seal is an oil seal, much like the ones on the front of the engine (crank and cams) that seals the exit point of the crankshaft from the back of the engine. Just as the front seals fail, rears can too.

 

Unlike the front seals, however, replacing the rear seal requires that the transmission be removed from the engine. If you think about the way the parts are connected, the driveline has to be separated to get the thing out.

 

You don't mention whether the car is a manual or an automatic but my philosophy is to always replace the rear main anytime I need to drop the gearbox, such as for a clutch replacement. If you do have a manual transmission, you might opt to hang in there till you need a new clutch. That's a personal decision as the leak is not likely to damage anything (except your olfactory glands).

 

As for cost, think of it as the cost of labor for a clutch replacement as the main seal itself costs almost nothing. Your spelling of "labour" suggests that you are outside the US somewhere, so I can't even begin to speculate on the costs.

 

Regards,

Adnan

if that is the proper term on a Subaru.A lot of them are plastic and prone to leak. I had mine changed when I had the clutch and rear seal done. It is very easy and cheap when the engine is out and the plastic ones have a high failure rate. The new one is metal.

Before yoy have the gearbox removed to do the seal.......clean the suspect area well......go for a test drive to warm everything up.....get underneath the vehicle with eng running...have a good look around immediatly below the turbo..Sometimes the oil leak is from the oil line that goes to the top of the turbo from the rear of the right head....if so the oil drps onto the exhaust up pipe..giving smoke and smells etc....good luck

I had a rear engine seal go out on my Subaru at around 100,000 miles. I put some of the Gold Eagle stop leak in it and it stopped. It was still not leaking at 288,000 miles when my idle pully came apart and the valves got into pistons. Many people here dont like to use these products, but I dont know of one person that has ever had a problem from using them. You can go to their web site for more details on their products.