Leaking valve seals

[jlaudio]

How much oil consumption is considered excessive with leaking valve seals? As I understood them its more of a slow drip into the cylinder and you get puffs of smoke upon startup due to this.
Is 2QT in 1400 miles on par for leaking valve seals? The dealer i bought my car from has determined and is replacing all the valve seals on both banks. Zero out of pocket cost to me, which i am very happy about.
I am somewhat skeptical that this is truely the root cause of my oil consuption issues. Anyone with any experience with leaking valve seals and how much oil they can consume?

[sircastic]

Valve seals generally leak under two circumstances:

1. This is the one most often observed by people. When the car sits, oil accumulation in the head around the valves leak past the seals and into the combustion chamber. This gives a puff of blue on start up.
2. On deceleration with the throttle closed or closed relative to engine speed there is a vacuum created because the engine cannot draw air through the intake. This is what gives you the engine braked effect. Because the engine cannot draw it's incoming charge through the throttle body it places the open intake valve under more of a vacuum and a leaking or weak valve seal will allow oil to be sucked into the combustion chamber. If you do a long deceleration from high RPM and the valve seals are really bad you might see blue smoke behind you.

Oil consumption from valve seals is generally only found on manual transmission cars because they provide engine braking verses automatic transmissions. Yes, if they are bad it can cause excessive oil consumption.

[B6JoeS4]

That seems pretty excessive, but I guess in a bad case it's definitely possible

[jlaudio]

interesting..
i provided them 10 qts of lubro moly 5w40 oil to start using once they fill it back up. i had blue puffs of smoke upon start up and sometimes warm start up too

[M|R]

I have occasional puffs of oil on startup as well. I think I replied to your other thread but anyways...

Im 99.9% sure my consumption is from leaky valve seals. I use about half a quart every 900-1000mi which isnt 'bad' by any means, but since I noticed it, I don't engine brake...at all. If I'm getting off an exit its clutch in, neutral, and use the brakes to slow down. I want to engine brake again but Im afraid this will cause the valve seals to begin leaking at a much, much quicker rate resulting in a drastic increase in consumption. Not to hijack the thread at all but if I am wrong about this someone please correct me because going to neutral every time I want to stop is getting old real fast.

2qt in only 1400 sounds excessive to me, but I could see it if you were to engine brake a lot.

And may I ask, what exactly makes the valve seals become faulty?

[The Councilman]

Could that be what this possibly is? Yellow oil light came on.. Didn't need much oil but it looks like there might be oil on the underside of the car... Not sure need to look closer.

[sircastic]

I have occasional puffs of oil on startup as well. I think I replied to your other thread but anyways...

Im 99.9% sure my consumption is from leaky valve seals. I use about half a quart every 900-1000mi which isnt 'bad' by any means, but since I noticed it, I don't engine brake...at all. If I'm getting off an exit its clutch in, neutral, and use the brakes to slow down. I want to engine brake again but Im afraid this will cause the valve seals to begin leaking at a much, much quicker rate resulting in a drastic increase in consumption. Not to hijack the thread at all but if I am wrong about this someone please correct me because going to neutral every time I want to stop is getting old real fast.

2qt in only 1400 sounds excessive to me, but I could see it if you were to engine brake a lot.

And may I ask, what exactly makes the valve seals become faulty?

If your valve seals are leaking, they're leaking. Engine braking isn't going to make them worse, it's only going to use oil.

With heat and age the valve seals, which are a rubber like material, become brittle, harden and crack. This is the most common reason.

[M|R]

If your valve seals are leaking, they're leaking. Engine braking isn't going to make them worse, it's only going to use oil.

With heat and age the valve seals, which are a rubber like material, become brittle, harden and crack. This is the most common reason.

This is what I am confused about. If I engine brake and say come to a stop at the end of an offramp, I can visually see a cloud of blueish smoke (oil) be blown past me. When I dont engine brake, I do not see it at all. I figured engine braking would cause them to become even worse as the seals are subject to more vacuum but I guess I am wrong.

I still wonder the root cause of this issue though, it seems plagued throughout this section. My car is an 06 and had the issue since I noticed it at 41k fyi. I remember someone telling me the precats being located so close to the engine caused cylinder temps to get high, resulting in the short life of valve stems but I am not sure how true that is as only half of me buys it.