Anybody ever have (and cure) excessive oil consumption issues due to valve stem seals?

My truck has a bit of a blowby issue, but with the oil trap I designed and installed, it isn't pushing much through the CDR, but it is still getting rid of about a quart every 100 miles or so.

It seems to "load up" on oil when sitting idling, and also whenever compression braking. It DOESN'T seem to do it whenever it is running positive boost, but anytime the boost drops off, it seems to start blowing a little oil smoke.

I'm thinking that the oil pretty much has to be getting past the valve stem seals, based on the symptoms, so I'm wondering if anyone else has had a similar situation, and replaced their valve stem seals, and seen significant improvement?

 

Sounds like seals to me. Mine did "load up" a little if it sat hot for about 5 min. Start up and pull away from the curb and there was some blue smoke but then pretty clear afterwards.

Emgine oil seems to burn pretty well in these engines, just ask the guys on OBN, oh wait, never mind Once the boost gets higher, so does the compression and combustion temps, so whatever leaks down will probably get burned.

When I tore into my engine, the valve seals were nice and crisp, some worn badly and most came off in more than one piece. After the rebuild, its using about 1 - 1.5 qts between oil changes. I sometimes forget to check the oil lately. Only 5000 on it though.

Also had some oil comsumption with my F150, but during a head gasket job, I replaced the stem seals and the problem was almost eliminated (that one had a mild rebuild as well in its recent history, so it couldn't have been rings).

 

what kind of oil are you using

 

Delo 400 LE 40wt

No doubt in my mind that a complete rebuild would cut the consumption down to nothing David85, and I know that valve stem seals alone can reduce it a lot in gassers. BUT I've also been told that since diesels have no throttle plate and therefore don't to build the kind of manifold vacuum that gassers do, that the condition of the valve stem seals have far less effect on oil consumption.

On the other hand it seems like I've also read postings on here from others saying that on THIS particular engine, they do make a significant difference.

Just trying to figure out whether it is worth doing...

 

I think your shooting yourself in the foot ......as well as oil seals possibly. Maximum recommended oil viscosities.

6.9-7.3 Engine oil requirements.

32F to 100F+........30wt

0F to 100F+..........15W-40

32F to way below freezing ........10W-30

With the new oils...... 0W-40 is a good choice too in extreme cold

 

I've been running the 40 wt to reduce consumption. You trying to tell me it might be increasing consumption? That makes NO sense to me.

BUT, lets not get sidetracked into an oils debate. I'm looking for specific info - the experience of those who have replaced their valve stem seals.

 

Well, my engine did push at least 400 psi on the lowest cylinder before the rebuild, so there isn't much else that could have caused my consumption problem.

 

AHHH! I see, well that puts a totally different light on your comments.

400 psi, huh? Why did you have to do a rebuild? Lose a rod bearing?

 

As it turns out, I wasn't far from it actually. But what happened was I lost all my glow plugs and several had no tips on them. I knew the truck had been run when the incident happened, so I figured it was possible that a tip had done damage to one or more of the pistons. Pulled the truck into the shop and pulled the heads and saw this:


....next thing to come out was the rest of the engine and my build had begun. I did have some bearing material pitting on one of the rod bearings, so it was probably for the best. The highest was 500 PSI, so there was a pretty wide range there too (manual calls for max variation of 25%). There was also some early head gasket problems starting. Still ran pretty good though.

BTW, don't use wellman glow plugs.....ever. not one still had a tip left on it, but a single beru glow plut was not only intact, but still working (I have it in my tool chest as a spare).

 

No chance of me using anything but Berus - ever. When Autozone was closing them out I bought 3 or 4 sets @ $3 a plug.

So I should be set for life on GPs...

Sounds like the valve stem seals probably are a big part of my problem and would be worth doing.

Anybody else got any experience/feedback on this one?

 

cheeper,
you done a leak down or compression test yet?

 

Never have done a leak-down, but my last compression check was 320-390 psi dead cold. No real problem in that area...

 

i'm just wondering why you think it's the valve stem seals.

 

Although I have never changed just the valve stem seals to reduce oil consumption, given the shape of all seals I have removed I would venture a guess that they could be where some of the oil is going.

Just valve stem seals will probably not eliminate all of the oil consumption, but it will probably reduce it.

Mine were about like a piece of old hard plastic they were so hard and brittle.

 

HOPEFULLY on Thanksgiving weekend I'm going to pull my motor and one of the things I'm going to change is the valve stem seals. I think my 7.3L leaks more oil than it burns but if I do mine before you I'll let you know how it turns out.