leaky vavle seals

[Midwst]

the engine valve seals are leaking on my Legacy. if I don't fix it, will it cause any damage?

[idosubaru]

how do you know the valve seals are leaking?

in general it shouldn't cause problems, depends how bad and why they are leaking.

[blitz]

I'd think that the only consequence would be an abnormally high rate oil consumption which can damage the engine if you don't keep the level up.

 

Also it'll take your cats down quicker.

[mwatt]

the engine valve seals are leaking on my Legacy. if I don't fix it, will it cause any damage?

 

are you talking about valve stem oil seals or do you mean valve cover gaskets/spark plug seals/valve cover bolt seals? Leaking valve stem seals will cause the engine to burn oil. Leaking valve cover gaskets and/or valve cover bolt seals will cause the engine to drip oil which will cause a burning odor.

[Midwst]

Leaking valve stem oil seals. Quite positive of the diagnosis. been here before on other cars. Suspect one problem is carbon build up in cylinder causing pinging. How expensive is a new cat? Mine pings terribly when car is shut off. Not restricted yet, but may be on its way. Junk yards won't sell me a used front pipe. Damn feds. Too many stupid laws.

Here are the symptoms just in case: blue smoke out tail pipe on initial start up. After warmed up, still smell a tiny bit of oil burning, no smoke. Oil consumption is very slight...maybe 1/4 to 1/2 qt every 2,000 miles....some of that is leakage...multiple small oil leaks.

[jib]

If you go for some decent length drives, the cat will most likely keep itself clean. Short tripping may allow it to get fouled. You may want to check both the end of the exhaust pipe and the O2 sensor periodically. If oil is getting to the end of the tail pipe, or if you are getting accumulations on the O2 sensor, you may want to have the seals replaced sooner, rather than later.

 

Although I hate to suggest snakeoils, there may be a seal swell additive out there that might slow down or remedy the problem, at least for a while.

 

If you really think you have carbon build up in the cylinders and it has not been on a high speed road trip for a while, take a trip. Alternatively, run the car down the highway at 4-5,000 rpm for 15 minutes and blow that stuff out.

 

Pre-cat days, you could slowly dribble water down the carb throat. The water would turn to steam and clean the cylinders out, much like a head gasket leak can leave a cylinder sparking clean, but I'm not sure how this would work with a catalytic converter and would be pretty concerned about doing it on my vehicle.

 

Jack

[Midwst]

Have done the water trick myself on cat cars. Never had problem...knock on wood. thanks for the tips. Will definately make use of them. Not sure about the snake oil thing....additives make me nervous.

[jib]

Have done the water trick myself on cat cars. Never had problem...knock on wood. thanks for the tips. Will definately make use of them. Not sure about the snake oil thing....additives make me nervous.

 

It's good to hear the "water thing" has worked for you on a cat car and yes, additives bother me too.

 

The only additive I'll recommend is Solder Seals Steer Seal. It's a pure additive for power steering systems. My Saab mechanic put me onto it when I was having Groaning issues with my Power Steering pump when it was cold and I thought the pump might have to be replaced. The Steer Seal softened the seals and the original pump was still in the car when it was totalled out at 250K and 17 years old. I've since used it successfully on another car with a leaky pump too.

 

BTW - aftermarket cats can be had for about $100.

 

Good luck with your subie,

 

Jack