Author Topic: 83 C20 knocking after finding low on oil  (Read 213 times)

Offline Scott Wayne

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83 C20 knocking after finding low on oil
« on: October 25, 2021, 10:59:17 PM »
Hey y’all. I made a rookie mistake and went too long without checking the oil, I guess this motor leaks/burns more than I thought. So a couple days ago it starts knocking and I added 4 qts before the dipstick level was where it should be, just to get home. The next day I drained all that, put on a new filter and added 5qts of Valvoline 10w40 high mileage, which is a full synthetic. I also added Restore oil additive.

The knocking has gotten better but it’s still there so I’m wondering if I did some permanent damage to the engine by running it that low? Is there any way to tell without pulling the motor completely apart how much damage I’ve done? This is my daily driver and I’m not a rich man so I don’t have a lot of options as far as rebuilding goes. Thanks for any help with my bonehead mistake. Hopefully I didn’t completely ruin my truck.

Offline JohnnyPopper

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Re: 83 C20 knocking after finding low on oil
« Reply #1 on: October 27, 2021, 12:10:37 AM »
Well bro, I don't need to point out the obvious.

The fact that the knock is better is not a nod that the engine didn't suffer bearing damage.

Two things to consider: you installed a light weight oil, even though it says 'high miles'. I would change it to a single viscosity, starting with 50w.

If that cures it great!

If not, I would look to another source of knock-age_ lifters. They are not as heavy as rods but sound almost as bad. Rislone is great for free-ing up those pesty beasts.
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction