Valve cover replacement Chevy 4.8. Always synthetic oil…

[FastLane]

I’ve owned my Silverado since new. 238000 kms on it. I ordered a new revised GM valve cover. Why? I changed the intake gaskets last week and had oil inside the intake manifold. GM revised the left valve cover to reduce oil being forced through the PVC system to the intake.

The truck has always ran synthetic oil at 5000 km OCI.

Pretty clean!!!

 

[Soft Cars]

Wow!

 

[jetman]

Yes, GM issued a Technical Service Bulletin, TSB 10-06-01-008M about 10 yrs ago for oil consumption problems. Part of the TSB was the new improve driver side valve cover with improved PVC baffling in it.
Here's the TSB: TSB 10-06-01-008M

 

[WylieCoyote]

Perfection.

 

[jetman]

In 2018 I purchased a very used GMC Yukon Denali w/6.2L. It was consuming 2 oz of oil per 100 miles. I immediately installed a catch can in the PVC vacuum line between the original valve cover and the intake manifold. It was catching 1 oz per 100 miles. The other 1 oz per 100 miles was leaking out of the rear main seal.

I found out about and performed the GM TSB, and I replaced the rear main seal.

Today, almost 5 yrs and 60k miles later the catch can catches 1 oz per 5k miles, and make-up oil is only 1/2 qt per 5k miles, and no leaks.

Old original design on top, new improved on bottom:

 

[Cujet]

That looks like it should!

 

[WobblyElvis]

It's nice and clean but are there any real benefits? If oil had been changed half as often [ OCI 6,000 miles], would there be more wear?
Time and money would have been saved.
Everyone makes their own choices. It sure doo look goood!

 

[addyguy]

At 3k synthetic oil changes I should hope it’s clean!

 

[Cujet]

It's nice and clean but are there any real benefits? If oil had been changed half as often [ OCI 6,000 miles], would there be more wear?
Time and money would have been saved.
Everyone makes their own choices. It sure doo look goood!

Absolutely. The varnish seen under the valve covers is the very same varnish that sticks the piston rings, and results in blowby, oil consumption and oil contamination. It is also the very same varnish that damages valve stems, oil pumps, oil pickup screens and so on.

There is absolutely no question that a well maintained engine lasts considerably longer, and will likely have zero internal repairs.

 

[Graham Piccinini]

Absolutely. The varnish seen under the valve covers is the very same varnish that sticks the piston rings, and results in blowby, oil consumption and oil contamination. It is also the very same varnish that damages valve stems, oil pumps, oil pickup screens and so on.

There is absolutely no question that a well maintained engine lasts considerably longer, and will likely have zero internal repairs.

+1 on that. If there is varnish in areas that are visible, then there is definitely varnish in areas that aren't as easily accessible.