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07-07-2024, 10:12 PM | #1 |
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1970 Chevrolet C20 Pickup - Motor Leaking Oil
I have a 1970 Chevrolet C20 350, 5.7 pickup truck. The motor is leaking oil. I am trying to get an idea of possible places were the motor is leaking oil and what is required to fix it.
If I was to clean the motor to have a clean motor and look for oil leakage, what is typically used to clean the motor? Also, what parts need to be covered if water is used? What are the places the motor would leak oil? Valve cover gaskets and head gaskets? Any other places? What is typically done to fix motor oil leakage? Replace valve cover gaskets? head gaskets? Anything else? Might it require removal of motor? Just trying to be well informed as I look for a mechanic or mechanic shop. Appreciate the help. |
07-07-2024, 10:37 PM | #2 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
I would start with cardboard placed under the Engine.
Then you can see a local point of the Major Leak. There are lots of cleaners and processes. Simple green or Purple power work. A person just has to be cautious about spraying on Wiring and electrical stuff.
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07-08-2024, 12:51 PM | #3 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
Any ideas on the age or mileage on the motor? On high mileage motors any gasket may be leaking. Cheap gaskets will fall before quality gaskets will. And any gasket can fail if improperly installed.
Common points that leak but don't cause other problems (Like a leaking head gasket may) The front and rear intake manifold gaskets. Rear main seal. Oil pan gasket. Front main seal. Fuel pump. Valve covers. This can be from bent or deformed covers as well gasket failure. There are more but these are the most common ones I've seen over the years. Replacing the PVC valve and hose can help as a collapsed hose or stuck valve can allow pressure to build in the crankcase. Generally if I have a really dirty engine I will take it to the DIY car wash and use their engine wash and the high pressure spray. Just stay clear of the upper part of the engine with the spraying. And wear some safety glasses. Old plug wires are susceptible to grounding out when wet so it's best to avoid the car wash if your plug wires are old or questionable. Taking some WD40 to spray the plug wires down after cleaning the engine is a good idea. You didn't mention what style of transmission. The front seal on automatics can leak as well as the seal around their dipstick tube adding to the mess. There are dyes you can add to your oil that in combination with a black light can help locate leaks. Some professionals swear by them as they make it easier to find the leak when clean oil is leaking. Good luck on your search.
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07-10-2024, 07:16 PM | #4 | ||
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
Small Block Chevy's just leak... it's what they do. Especially if it's the original engine with high miles and all original gaskets. A lot of them leaked in spots very shortly after leaving the show room floor.
A lot of leaks at the rear of the engine are caused by leaking valve cover gaskets, or the oil pressure sending unit on the back of the block behind the intake manifold. Gary
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07-10-2024, 10:09 PM | #5 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
Best idea is to grab a can of WD-40, a roll of paper towels and a flat blade #2 screwdriver and your favorite engine degreaser and a pocket full of quarters and head to the quarter car wash and clean the engine and engine compartment as well as you can. WD-40 and towels and screwdriver are to dry the inside of the distributor cap out if it gets condensation in it. get it good and clean and start checking closely .
I've got a 68 292 that ran great but was given to me because in a 180 mile road trip it leaked more oil than it used gas dollar wise. The guy bought the truck drove it home and pulled it in the garage and did an engine swap. That one is going in my 48.
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Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around. |
07-10-2024, 10:21 PM | #6 | |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
Quote:
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07-10-2024, 10:33 PM | #7 | |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
Quote:
This was after they pressure washed the engine and engine compartment before pulling it. It's getting painted 48 Chevy truck engine gray with a serious amount of finned cast aluminum on it.
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Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around. |
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07-10-2024, 11:18 PM | #8 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
Brutal! "Take a Saws-All to that exhaust pipe! I want that engine out of here, now!" BTW, I hope you are doing away with that puny air filter.
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07-10-2024, 11:30 PM | #9 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
Quarter car wash??? my local one is 4 bucks. lol
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07-10-2024, 11:42 PM | #10 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
For sure.
48 Chev did say a Pocket full So He Knows.
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07-28-2024, 07:15 PM | #11 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
Thanks, appreciate your help. Going to use this, as I work on fixing this issue.
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07-28-2024, 07:32 PM | #12 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
I really like the Dawn Powerwash for degreasing . Didn’t think it work all that well but I was impressed. If you really want it clean use a heated pressure washer. I rented one and it was well worth it never even took it off the trailer hose was 20 ft long . Like others have said it’s most likely the intake /valve cover or oil line .
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07-29-2024, 03:19 AM | #13 | |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
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07-29-2024, 08:17 AM | #14 |
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Re: 1970 Chevrolet C20 Pickup - Motor Leaking Oil
The motor I took out and replaced ran well but was leaking a lot . Guess the prior owner tried to seal it up . Big ol gob of RTV on the valley of the intake front and back and it still was leaking . I’m going to reseal it and put it in the Anniversary truck
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