This is going to sound odd to some of you, but bear with me...

For reference: 2000 Monty Sport, 3.0, 2WD, ~170K miles

I had the typical noisy valve lash adjusters problem. The ticking came and went, and was annoying (and embarrassing) but not critical. My oil pressure idiot light came on at startup, but went out immediately, so I didn't think oil pressure (pump) was the problem.

I read up as much as I could about it, tried all of the "fixes" (revving up and down for 5 minutes, different weight oils, oil additives/cleaners...) - nothing worked. There was pretty much no ticking right after an oil change, but it always came back within the first 100 miles. Note: I also keep .5 to a full quart extra oil in the engine.

I was planning on digging the old adjusters out and replacing them (along with spark plugs and other assorted maintenance items) and was on the verge of ordering them online.

But first I needed to replace the rear camshaft plug O-rings because I had a small amount of oil leaking from at least one of them. Got them from the dealer for $4+ each and installed them this past weekend. (The driver's side is a PITA, by the way - it didn't come out easily at all...) Nothing else was changed, no oil added (I keep it topped off).

So the new O-rings are in, started it up, and guess what? NO VALVE ADJUSTER NOISE! No way, no how; not cold, not idling in traffic, not during deceleration, not after a long drive... These are all of the times the lifters used to tick, and I can't GET them to make noise. I figure that the little bit of pressure leaking from the older O-rings was keeping the valve adjusters from being fully primed/lubricated...? I don't know how much pressure is supposed to be in the valve train, but this cannot be a coincidence. In all of my research, I did not see one word about leaky O-rings (and a lack of adequate oil/crankcase pressure) being the culprit.

So for those of you who have the dreaded "lifter tick" on these engines, you might try replacing the (rear) camshaft plug O-rings before pulling that upper manifold and those valve covers off - even if they're not leaking oil, they might be leaking air pressure. $9 and a ratcheting 12mm box-end wrench (plus a 14mm, ratchet extensions and a U-joint to remove the tranny dipstick bolt) beats hundreds of dollars and PITA job every time.

I seriously do not believe that it was coincidental that the valve adjusters just stopped ticking at this time for no other reason whatsoever. I welcome opinions from those of you who know these (6G72) engines very well, and can state what the internal pressure would be in the crankcase/heads.

 

Interesting find. I had a 97 GDI engine before buying my 2006 MVIC and had much the same symptoms as you described. Even ran full synthetic with limited sucess. Didn't drip a drop of oil but as you mentioned possibly loss of air pressure in valve train was enough to keep hydroulic lifters from operating correctly. As long as it has worked then good job on finding problem and sharing experience.

Jim

 

I don't know. Kind of doubt valve adjuster knock can be related to the oil seal. First of all there is no air pressure in the valve train. If you have air there, that what causes the valve adjuster knock (air compresses under pressure). Second, the area above the camshaft and valves is not pressurized in fact it is vented out to the plenum via a PCV valve. The oil leak past the cam position sensor is just that - an oil leak. The oil does not squirt out of there under pressure.
I wonder if this "fix" on an unrelated component is just a coincidence.

 

I agree with Hunter, I really don't see how that can affect the lash adjusters at all.

 

Like I said, it sounds odd. But this is a definite change in the oiling of the lash adjusters. Going on a week now without a tick. The only thing I can imagine that changed is the positive (or vacuum) pressure in the crankcase and/or valve train.

 

awesome

 

Filmy--any update you'd like to share with 2 years+ under your belt? I'm redoing my 6G72 now FYI.