Valve stem seals and GTDI

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Not marketing at all (not sure about the claims for the oil). Leaking valve stem seals has caused valve deposits since the beginning of the ICE.
 
The engineers that make valve stem seals tell me they are designed to leak a bit of oil to lube the valve guides.
 
Originally Posted by Kestas
The engineers that make valve stem seals tell me they are designed to leak a bit of oil to lube the valve guides.

Yep.
 
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Originally Posted by ka9mnx
Originally Posted by Kestas
The engineers that make valve stem seals tell me they are designed to leak a bit of oil to lube the valve guides.

Yep.


I understand that, I meant the part about the valve deposits forming on GTDI intake valves caused by this. If you browse the EcoBoost forums, everyone is pushing oil separators and catch cans hard - the same goes for other brands of GTDI engines. The assumption was the deposits were formed primarily by oil from the PCV system, no one ever mentioned the valve stem seals. I know from experience that the factory PCV oil separators on my EcoBoost engines have been very effective. The only thing they catch are volatile vapors that coalesce and burn very readily. Almost all the oil I found in the intake tract came from the turbochargers.
 
Last edited:
Originally Posted by metroplex
I understand that, I meant the part about the valve deposits forming on GTDI intake valves caused by this. If you browse the EcoBoost forums, everyone is pushing oil separators and catch cans hard - the same goes for other brands of GTDI engines. The assumption was the deposits were formed primarily by oil from the PCV system, no one ever mentioned the valve stem seals. I know from experience that the factory PCV oil separators on my EcoBoost engines have been very effective. The only thing they catch are volatile vapors that coalesce and burn very readily. Almost all the oil I found in the intake tract came from the turbochargers.

Because they're uninformed. Leaky stem seals contributing to consumption, piston deposits and IVD's is a bona fide "thing". And so is recirculated oil vapour via the PCV.

A lot of times the valve guide over time develops play which in turn accelerates wear on the seals. Sometimes it's lack of adequate lubrication or sometimes the seals just plain wear out..they do have a finite lifespan.
 
Early (circa 2007) DI engines had poor/inadequate PCV designs and the aftermarket industry has been cashing in on the "need" for catch cans ever since. Especially with the performance crowd because as a group they lean towards being obsessive compulsive.
 
anything can contribute to DI deposits + turbod engines are worse, add boost increase cylinder pressure + some-more oil goes by the rings. manufacturers know the problem but are owning up for!! you guessed financial reasons!! you are seeing more engines with both for a reason, but due to cost it will take a while + likely cheapies will never see both. i will NOT own a CVT or DI only vehicle EVER!!!
 
DI issues have largely been proven to be caused by abusive maintenance, ie: overly frequent oil changes with the wrong oils. Particularly exacerbated by enthusiasts and DIY'ers who "think" they're doing their engines a favour by changing more frequently than spec. The problem has been particularly vexxing for the manufacturers who just can't contemplate why someone would change oil more frequently than the manuals specify.

When I did a meta analysis of complaints on an enthusiast forum a few years back, literally everyone, of close to 100 posters in a several hundred page thread, admitted to changing considerably more frequently than specified.

Its literally insane that even on BiTOG we have people advocating more frequent than spec'ed OCIs for DI engines under some theory that DI engines specifically 'need' such. Despite no evidence existing in UOA or otherwise for such.
 
How can changing your oil too frequently cause DI issues? I know some advocate more frequent oil changes in the Ecoboost engines due to fuel dilution and shear, and them being generally hard on the oil? I'm curious as to why changing the oil more often could lead to DI issues
 
Originally Posted by metroplex
https://team.valvoline.com/diy/truth-behind-carbon-buildup

This may be marketing but it is the first I have heard of valve stem seal leakage contributing to deposit buildup.

Is there any truth to this? Kind of makes sense given my experience with catch cans on EcoBoost.

Of course, before I replaced the worn valve-stem oil seals in my old Corolla, the spark plugs would be covered with oil ash quickly. After I replaced them, I no longer had oil-ash deposits on the spark plugs. The same would apply to the intake valves in a GDI engine, as they are not cleaned by the fuel. You will still get oil and ash deposits on the GDI intake valves through the PCV oil mist (liquid oil droplets) though.
 
Originally Posted by pitzel
DI issues have largely been proven to be caused by abusive maintenance, ie: overly frequent oil changes with the wrong oils. Particularly exacerbated by enthusiasts and DIY'ers who "think" they're doing their engines a favour by changing more frequently than spec. The problem has been particularly vexxing for the manufacturers who just can't contemplate why someone would change oil more frequently than the manuals specify.

When I did a meta analysis of complaints on an enthusiast forum a few years back, literally everyone, of close to 100 posters in a several hundred page thread, admitted to changing considerably more frequently than specified.

Its literally insane that even on BiTOG we have people advocating more frequent than spec'ed OCIs for DI engines under some theory that DI engines specifically 'need' such. Despite no evidence existing in UOA or otherwise for such.



so your point is what? wrong oil ? or changed too early? either needs an explanation for how this either singly or in combination could worsen a DI engines tendency for deposits on intake valves.
 
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