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Paul S

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I understand that this is a Cadillac Forum but I need advice on an '88 Corvette. It has 38,000 miles on it, sits in the garage all the time, and I have never change oil in it since I have owned it. Sounds bad I know but it had a fresh oil change when I bought it and I have only put about 4,000 miles on it since.

I changed the oil using Valvoline 5W30 oil, and now the lifters are making a racket that are mostly noticably while idling. It never did this before I changed the oil.

Any comments or suggestion would be greatly appreciated.

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Leaving a car sit with fresh oil for a long time without driving it is OK, but:

  • The oil must be really fresh. Something like 100 miles after a change is OK.
  • The car must be protected from moisture, particularly the engine, transmission, U-joints, differential, half-shafts, hubs, and brakes.
  • Change the oil and filter again when you start to drive it again.
  • You have better luck using synthetic for storing cars beause it is less absorbent of moisture - but it still must be fresh. Clean, fresh dino oil is just fine for storage if you keep the car in a clean, dry place that doesn't get hot, then cold, then hot, etc.

The fact that the lifters are clattering is a really big red flag that you don't have oil pressure. This could be due to a problem with the oil pickup, the oil filter, or the bypass. I'm assuming that you checked the oil and it isn't foamed up, low (bad filter gasket seal) or turned to mud from moisture in the bottom of the pan or some such. I would NOT drive the car that way.

Valvoline 5W-30 is a good oil. That's not the problem.

Since this just started when you changed the oil, my best guess is that you have a pickup problem. I would try just letting it sit overnight to see if the new oil permeates the oil screen and such and the problem goes away to the extent that you can drive the car. There is an outside chance that the new oil filter is bad or that the bypass has stuck but that's a reach. I it does go away, I would drive the car gently just once to get the engine hot and run the new oil thorugh it to clean it out, then change it again.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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2nd time I am recommending this in a week, but drain a quart of oil, & replace with a quart of Marvel Mystory oil in the crankcase. also put 8 ounces of MMO in a fresh tankful of gas. - and I also suggest letting it sit. you may need to change the oil after it starts up a few times.

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Texas Jim and winterset have excellent suggestions. If that doesn't do it, I think you need to put an oil pressure gauge on it, if the Corvette doesn't already have one.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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How long was the car sitting before you changed the oil? If it's been sitting for an extended time, the lifters will be dry and it takes some time to get them filled with oil.

I'm thinking 10W-30 is the correct oil for that car but am not sure - what does the owner's manual or the oil fill cap say?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Have you checked your lifters for play? Try some assembly lube and see if it helps to run it safely til it gets sufficient flow

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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  • 1 month later...

Sorry it has taken so long to get back to this post, but happenings other than car issues required my immediate attention.

Base on all your comments I decided to re-evalueate the problem when I realized the oil pressure would reach as high as 80psi when cold, and a more normal 60psi when warmed up. So I removed the fan belt when the engine was cold and started the engine and allowed it to run till the engine had warmed up. I found that the noise had gone away. Just the normal engine sound was all that was present. I then spun all the pulleys by hand and found that they all were silent and smooth except for the air pump. It would groan when I spun it and stop immediately when I removed my hand from it. I disassembled it and found that the grease in it had done what grease does after 25 years, which is turn in to something that resembles glue. I tried cleaning it and relubing it but it only lasted for a few minutes and the noise returned. I was able to get a new one and so far it has worked flawlessly and the noise is gone.

I wish to thank everone who responded to my posting as it caused me to rethink the problem and arrive at a solution. (It sure sounded like lifters!) Thanks again.

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