1970 Chevrolet C20 Pickup - Motor Leaking Oil

[ggalv]

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.

[Getter-Done]

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.

[HO455]

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.

[GASoline71]

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

[mr48chev]

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.

[Steeveedee]

Originally Posted by mr48chev

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.

Wow. That would be his loss. A few dozen dollars for gaskets, and yer done. Crazy.

[mr48chev]

Originally Posted by Steeveedee

Wow. That would be his loss. A few dozen dollars for gaskets, and yer done. Crazy.

He bought it with the very nice ready to drop in engine sitting and waiting for it. The truck was a nice original 4 speed truck that ran great but leaked oil everywhere that one can leak.

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.

[Steeveedee]

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.

[BROWN 70]

Quarter car wash??? my local one is 4 bucks. lol

[Getter-Done]

Originally Posted by BROWN 70

Quarter car wash??? my local one is 4 bucks. lol

For sure.

48 Chev did say a Pocket full So He Knows.