2002 H6 - no compression!

[plain OM]

Originally Posted by cardoc

. . . This is a good example of why you should use a cleaner in the fuel, intake and quality oils. And don't go a long time between oil changes. If this wasn't a Subaru, it would be trashed.

FFR5445: What is the record for the car in relation to cardoc's suggestions? (Any reason for the build up?) Also, was the car bought new, or second hand with an uncertain past?

[Novablue]

Originally Posted by FFR5445

The cylinder head is off. No bent valves, no holes anywhere. At first I was all upset because nothing was obvious and this is just so strange. But then I took a closer look. LOTS of carbon build up on cylinder and around valve and valve seat.


What do you guys think? Did I figure it out, or did I take apart my wife's car for nothing!?!?!?

No you didn't.

Take the heads to a shop that specializes in cleaning and machining. Not sure about the block because you didn't show picts of that.

This engine shows poor maintenance over it's life possibly cheap fuel and lack of cleaning. Once it's cleaned up I think you'll be happy assuming nothing is bent which is why you should have it checked out. It's possible to not "see" a bent valve. Get estimates and see if you want to go new or clean/repair.

Carbon build up causing no compression is possible in situations like this.

I agree with Cardoc. Other manufacture engines would not be worth repairing at this point because there would be more damage.

As to using sea foam, it works if you use it like Cardoc says, but I have had good luck by trying to make sure I always use premium fuel. I've put 100k on 3 engines now and all of them look like new with those miles. I have yet to use sea foam but I do use good synthetic oil and Chevron or Texaco fuel. "An ounce of prevention is worth a pound of cure."

[cardoc]

A whole can of Sea Foam in the gas tank twice a year.

Up to two times a year, run the Sea Foam through a vacuum port on the intake with the engine running to dissolve the oil deposits created by the crankcase venting system. This would depend on he mileage you drive. Round it to every 15k.

Oil breaks down and creates carbon deposits within the engine. That's what that crusty brown caking is. When you go a lot of miles between oil changes or let it run low this occurs quicker. The carbon is baking to everything it contacts.

Higher quality fuel keeps the fuel system cleaner as well as improve the overall performance of the engine.

If you look at the photo of the full head you will see the oil build up on the edge of the combustion chamber on the bottoms side under the exhaust valves. This may be an indication of ring wear or valve seal wear allowing oil to seep into the chamber after shut down and settle on the base of the chamber. And that's a lot of build up. It could have been from more recent or over a period of time. I think more recent just because of its coloring. It's not burned up completely.

[1 Lucky Texan]

this thread is crazy.

is there someway the PCV system could have led to this?

if that color was on the plugs - what would it indicate?

[cardoc]

Originally Posted by 1 Lucky Texan

this thread is crazy.

is there someway the PCV system could have led to this?

if that color was on the plugs - what would it indicate?

The PCV system allows the engine to pull gases out of the crankcase that are created normally from heat and pressure. At the same time it sucks oil particulates. The particulates adhere to the surfaces of the induction system and over time will thicken. This changes the flow of air. It adheres to the intake valves as well as the oil is pulled through to the combustion chamber. This is that black film you often see on the trottle body. When crankcase pressures are high during high engine rpm, the effect is greater.

Abnormally high crankcase pressure can be due to small things like using heavy oils to ring blowby.

On this engine it appears the valve seals are bad. When the engine is stopped, valves remain open. The oil deposit at the base of the head indicates the oil was draining into the head every time the engine was stopped and the next time it was started it probably smoked a bit until it burned off the loose oil in the chamber. Judging from the photo it looks to have been going on a while. It just got to the point the carbon and sludge lodged the valves open.

It is possible that a clogged PCV valve could accelerate internal leaks. The pressure will find a way out. Given the mileage of his engine, the seals were most likely worn.

[Novablue]

Originally Posted by cardoc

The PCV system allows the engine to pull gases out of the crankcase that are created normally from heat and pressure. At the same time it sucks oil particulates. The particulates adhere to the surfaces of the induction system and over time will thicken. This changes the flow of air. It adheres to the intake valves as well as the oil is pulled through to the combustion chamber. This is that black film you often see on the trottle body. When crankcase pressures are high during high engine rpm, the effect is greater.

Abnormally high crankcase pressure can be due to small things like using heavy oils to ring blowby.

On this engine it appears the valve seals are bad. When the engine is stopped, valves remain open. The oil deposit at the base of the head indicates the oil was draining into the head every time the engine was stopped and the next time it was started it probably smoked a bit until it burned off the loose oil in the chamber. Judging from the photo it looks to have been going on a while. It just got to the point the carbon and sludge lodged the valves open.

It is possible that a clogged PCV valve could accelerate internal leaks. The pressure will find a way out. Given the mileage of his engine, the seals were most likely worn.

It may sound redundant but I second this post.

[FFR5445]

PCV checks out good. Valve seals have been bad for the past 2 years and 40k miles so this engine failure doesn't come as a surprise. It has 160k on it now.

I'm debating whether or not to just throw a JDM engine in it. Aside from the hours and hours of cleaning, these timing covers are ridiculous and must have over 20 o-rings and 100 bolts. There are a lot of potential leak points.

I'm going to call some engine machine shops tomorrow for a few quotes on a valve job. Do I leave the cams on so they can do the valve adjustment too? What should I expect to pay?

Head gasket set seems to run about $250, plus water pump $60, valve seals $35. Don't think I would touch much else. I know people have problems with the chain guides but these are in perfect shape.

[1 Lucky Texan]

seems like oil usage would have been much worse than 1qt/4K miles . Does poor oiling lead to this? overheating?

[cardoc]

Originally Posted by 1 Lucky Texan

seems like oil usage would have been much worse than 1qt/4K miles . Does poor oiling lead to this? overheating?

Not necessarily. If that deposit was liquid, it would have a smaller mass, but the large amount of deposit at the base indicates it got worse quick. I'd bet the engine was close to a quart low when he pulled it.

As far as the machine shop, I don't know about up where you are, but the shops down here will do the labor, the owner has to bring the parts. They can't get them through their suppliers. Weigh the cost. You also have to have the Fuji Bond or equivalent and a lot of it. It can add up in cost. You can't use regular RTV and not expect a leak. If it goes to a shop, leave the cams on.

If you go with replacement, you could recoup some cost selling it for rebuild or aluminum scrap.

[1 Lucky Texan]

OK - I was researching for another post, ran across the following; 2001 LLBean Won't Start in Spring, Flooded Engine

pay attention to where the compression was measured.