Stupid me, no oil

Grub54891

Admiral
Joined
Jun 17, 2012
Messages
6,079
Had a leak on the intake myself. Had the heads re-done and they milled them flat. I used the end gaskets for the intake that came with the kit. Turns out when you shave the heads, the gasket is too thick. It squished out. My fix was to remove the remains of the gasket without removing the intake and using a good engine silicone in the area after cleaning with brake clean. Never leaked again. Had another one that the oil sender was leaking badly.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,693
Just thought of another thing
Does this engine have the dipstick that hooks up to the drain plug in the pan? If so, there is supposed to be a rubber plug where the normal dipstick would go. If this rotted out or fell out you’d lose a LOT of oil! Starboard side of the block right at the bottom of the block
 

Pmt133

Chief Petty Officer
Joined
Jan 6, 2022
Messages
575
Just thought of another thing
Does this engine have the dipstick that hooks up to the drain plug in the pan? If so, there is supposed to be a rubber plug where the normal dipstick would go. If this rotted out or fell out you’d lose a LOT of oil! Starboard side of the block right at the bottom of the block
My machinist actually peened in a stainless ball into that hole for that reason... think he said if that starts leaking I'll have bigger problems to worry about or something.
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,366
what can leak in the back of a GM V6?
Intake manifold gasket (especially where it contacts corner where block meets heads, meets intake)
Valve cover gaskets
Oil pressure sensor (if it screwed into the block back there)
Distributor missing gasket / o-ring where it enters intake
Doesn't look like any of those.

Rear main seal.

Only real bad one is the rear main. All others can be found by reaching back there and feeling for oil, start at the top and work down. Good lighting and mirror helps.
I can see oil at the rear base of the engine, that's it.
I just saw a super powerful black light on South Main Auto’s you tube. Put some dye in the oil & it will be obvious!
Well, I can see oil already. Everything forward was cleaned off, and there's nothing leaking above the head that I can see. So how would the light help? I don't think there's anything I'm missing that wouldn't require an engine pull to access.
Just thought of another thing
Does this engine have the dipstick that hooks up to the drain plug in the pan? If so, there is supposed to be a rubber plug where the normal dipstick would go. If this rotted out or fell out you’d lose a LOT of oil! Starboard side of the block right at the bottom of the block
I don't think so. I have the pan from the Blazer I pulled the motor from. Drain is on the port side, dipstick is starboard. Good thought though
 

04fxdwgi25

Chief Petty Officer
Joined
Mar 25, 2022
Messages
539
Some reason, I only considered leaks high on the engine. What about the pan itself? Maybe the gasket got borked when installing. I have seen a couple of V6 pans crack back around the rear main area.
Did the oil pan have any rust on it when installed?

Steel oil pans and damp bilges don't get along well.
 

tango13

Petty Officer 3rd Class
Joined
Mar 10, 2015
Messages
75
Do you think your leaking a qt every 10 hours or burning? Do the 4.3's have the oil pressure sending unit in the back of the motor like the V8s? If so, maybe your leak and slightly off pressures are stemming from that.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,693
Some reason, I only considered leaks high on the engine. What about the pan itself? Maybe the gasket got borked when installing. I have seen a couple of V6 pans crack back around the rear main area.
Did the oil pan have any rust on it when installed?

Steel oil pans and damp bilges don't get along well.
You really have to spray them with Corrosion X every few years. I’ve been doing that and my 1988 4.3 still has the original pan & it’s been kept on a salt water mooring for 20 seasons 5/6 months each season.
 
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