1997 Silverado 5.7L Synthetic Oil Experience

[biscaynekid]

I have 215,000 miles on my truck...owned it since 81,000 miles.

Truck has always run quiet...I mean absolutely no valve tap at start up or after warm up.

Never any serious problems. I have used 5w30 Conventional oil...always. Well, after being prodded to 'do it', I switched to Full Synthetic 5w30.

No problem for awhile. Then, about 4,000 miles into my synthetic oil change I started to hear, very faint, valve tap at start up. It would quickly go away. I paid more attention as the miles went on.

I noticed the valve tap was lasting longer before it quiet down. I checked my oil level, it was fine. I did noticed slight condensation and a yellowish tint on the rim of the oil filler cap and on the walls of the  oil filler tube. Dipstick was clean. Well, I asked myself why all of a sudden am I noticing these little things. I decided the only thing I had done was switch oil. I decided to go back to Conventional oil, but not all the way. I switched to 'Synthetic Blend'. All was well 2,000 miles into the 'blend' oil change, including the condensation on the oil filler cap and oil filler tube. Five days ago I started the truck up in the morning. Valve/lifter tap was LOUD. Oil pressure was good(45-50). After a minute the noise went away. I drove to work and all was quiet.

I completed my work day and got in the truck. I cranked it up and terrible Valve/lifter tapping. I sat there idling about 2 minutes...got a bit quieter, but still noisy.

I headed home. A mile down the road all noise went away and stayed away.

I stopped on the way home and bought Conventional Oil. I changed the oil and filter. I am all conventional oil now.

 

The truck made a very slight tap on the first start up, but hasn't made a peep since.

It sat over the weekend form Friday until Monday morning. I cranked it Monday morning and absolutely no tap or noise.

 

I'm sticking with what's given me reliability for 215,000 miles.

[KARNUT]

6 minutes ago, biscaynekid said:

I have 215,000 miles on my truck...owned it since 81,000 miles.

Truck has always run quiet...I mean absolutely no valve tap at start up or after warm up.

Never any serious problems. I have used 5w30 Conventional oil...always. Well, after being prodded to 'do it', I switched to Full Synthetic 5w30.

No problem for awhile. Then, about 4,000 miles into my synthetic oil change I started to hear, very faint, valve tap at start up. It would quickly go away. I paid more attention as the miles went on.

I noticed the valve tap was lasting longer before it quiet down. I checked my oil level, it was fine. I did noticed slight condensation and a yellowish tint on the rim of the oil filler cap and on the walls of the  oil filler tube. Dipstick was clean. Well, I asked myself why all of a sudden am I noticing these little things. I decided the only thing I had done was switch oil. I decided to go back to Conventional oil, but not all the way. I switched to 'Synthetic Blend'. All was well 2,000 miles into the 'blend' oil change, including the condensation on the oil filler cap and oil filler tube. Five days ago I started the truck up in the morning. Valve/lifter tap was LOUD. Oil pressure was good(45-50). After a minute the noise went away. I drove to work and all was quiet.

I completed my work day and got in the truck. I cranked it up and terrible Valve/lifter tapping. I sat there idling about 2 minutes...got a bit quieter, but still noisy.

I headed home. A mile down the road all noise went away and stayed away.

I stopped on the way home and bought Conventional Oil. I changed the oil and filter. I am all conventional oil now.

 

The truck made a very slight tap on the first start up, but hasn't made a peep since.

It sat over the weekend form Friday until Monday morning. I cranked it Monday morning and absolutely no tap or noise.

 

I'm sticking with what's given me reliability for 215,000 miles.

That’s the funniest story I’ve ever read. I have dozen of stories with totally different results. Starting in the early 80s. Including my latest 02 Avalanche with 180K miles on it. Conventional oil better than synthetic? Tons of vehicle manufacturers disagree. But it’s your ride, have at it.

[Grumpy Bear]

36 minutes ago, biscaynekid said:

I have 215,000 miles on my truck...owned it since 81,000 miles.

Truck has always run quiet...I mean absolutely no valve tap at start up or after warm up.

Never any serious problems. I have used 5w30 Conventional oil...always. Well, after being prodded to 'do it', I switched to Full Synthetic 5w30.

No problem for awhile. Then, about 4,000 miles into my synthetic oil change I started to hear, very faint, valve tap at start up. It would quickly go away. I paid more attention as the miles went on.

I noticed the valve tap was lasting longer before it quiet down. I checked my oil level, it was fine. I did noticed slight condensation and a yellowish tint on the rim of the oil filler cap and on the walls of the  oil filler tube. Dipstick was clean. Well, I asked myself why all of a sudden am I noticing these little things. I decided the only thing I had done was switch oil. I decided to go back to Conventional oil, but not all the way. I switched to 'Synthetic Blend'. All was well 2,000 miles into the 'blend' oil change, including the condensation on the oil filler cap and oil filler tube. Five days ago I started the truck up in the morning. Valve/lifter tap was LOUD. Oil pressure was good(45-50). After a minute the noise went away. I drove to work and all was quiet.

I completed my work day and got in the truck. I cranked it up and terrible Valve/lifter tapping. I sat there idling about 2 minutes...got a bit quieter, but still noisy.

I headed home. A mile down the road all noise went away and stayed away.

I stopped on the way home and bought Conventional Oil. I changed the oil and filter. I am all conventional oil now.

 

The truck made a very slight tap on the first start up, but hasn't made a peep since.

It sat over the weekend form Friday until Monday morning. I cranked it Monday morning and absolutely no tap or noise.

 

I'm sticking with what's given me reliability for 215,000 miles.

 

Does this mean you believe Synthetic oil CAUSES condensation? Water in the oil will cause aeration and that wreaks havoc on hydraulic systems. Thing is generation of water has nothing to do with the base oil. Has more to do with the state of engine tune and prevailing conditions of weather and operation. You have something else going on there. A few ideas:

 

Short tripping in cold weather.

PCV system issue. 

Water thermostat malfunction. 

Head gasket leak. 

[richard wysong]

5.7 could be intake gaskets seeping. If you have unexplained coolant loss, even just a little it is time to do the gaskets BEFORE they blow out and leave you stranded and possibly damage the engine

[Silverado4x4]

I agree with the others the Conventional oil is hiding your problems. The synthetic oil most likely cleaned you motor out some and exposed the problem as Richard said you have a intake or maybe a head gasket issue and going back to Conventional oil is hiding the problem again. The yellow tint is moisture in your motor and its on borrowed time.

Edited March 18, 2023 by Silverado4x4

[biscaynekid]

Still absolutely no ticking/tapping.

Here's an interesting link: https://www.mccluskeychevrolet.com/benefits-to-sticking-with-conventional-motor-oil/

[KARNUT]

38 minutes ago, biscaynekid said:

Still absolutely no ticking/tapping.

Here's an interesting link: https://www.mccluskeychevrolet.com/benefits-to-sticking-with-conventional-motor-oil/

Both my Honda dealership and my GMC dealership have switched from synthetic blend to full synthetic. My Acura Intagra Type R a high red line vehicle. At 70 in 5th gear it’s cruising at 4K RPMs. It was using a blend only being serviced at the dealer. The last few years changed to full synthetic. My 02 avalanche the same experience. There of course are exceptions.

[diyer2]

How often did you do oil changes.

I agree the synthetic was cleaning up the sludge.