some bad news - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ocbaud · 10-01-2006, 11:25 PM

truck has an oil leak

looks like it may be the rear main seal
its dripping down the back of the oil pan.

its only small, so nothing major to worry about.

how bad is it gonna suck to fix this?

Russell · 10-02-2006, 01:57 AM

Not that bad... If you have a two piece seal, you just need to undo the engine mount bolts, and jack it up high enough to get the oil pan off. You then remove the rear main cap, use the seal from the bottom half to push the top half out, then stick some oil on the new one to lube it up, slide it in, making sure you center it, then lube up the bottom one, put it into the main cap, torque the maincap back down, put a single peice silicone pan gasket onto the oilpan, torque it down, drop the engine back down, then change your filter, put new oil in, and go.

However, that said, if your truck has been sitting for a while, drive it for a few days and see if the leak goes away. Old seals dry up, and start leaking, but seal up once they've soaked in oil for a while.

MylilBowTie · 10-02-2006, 04:29 AM

I would get a mirror (small telescopic kind) and look at the back of the intake end seal. Some other stuff to look at while your there.

Distributor base gasket, oil sending unit / mechanical gauge tubing, valve covers, drain plug gasket, rear main area from under the truck. You should be able to see it with a flashlight to see if its wet with oil. Take the transmission inspection plate off and look at the crankshaft where the flexplate bolts up to it on the engine side. If that is dry it could be the oil pan gasket in the rear. I had a problem with my one piece oil pan gasket leaking in the front. This is because I didn't put silicone in the front of block. It is in the area where the timing chain cover and block meet. You need to have a put a ball of sealant there on both sides. As well as the rear where the rear main and oil pan meet. That is the only sealant you need with the one piece oil pan gasket from fel-pro.

72C203503ONTHETREE · 10-02-2006, 07:37 AM

Shouldnt be too bad, maybe a a full days job if you rake your time. Biggest pain is getting the oil pan back on while trying to keep the gasket in one place and not moving it around. MIght want to replace the oil pump while you have the pan off if you have a lot of miles on it. New pumps are under 25 bucks and its cheap insurance. Also check a couple rod bearings, they are easy to replace while in the engine.

bigblock73 · 10-02-2006, 08:06 AM

Quote:

Originally Posted by 72C203503ONTHETREE

Biggest pain is getting the oil pan back on while trying to keep the gasket in one place and not moving it around.

If you get the Fel-pro one piece gasket, it simplifies things tremendously!

Clos'84TX · 10-02-2006, 08:15 AM

Quote:

Originally Posted by bigblock73

If you get the Fel-pro one piece gasket, it simplifies things tremendously!

Yep, that what i used --One piece- and crush proof, really worth the extra time and money!.... didn't even have to jack up the engine-nor did I have remove motor mounts.

10-01-2006, 11:25 PM	#1
ocbaud Garage Queen Material Join Date: Oct 2002 Location: USA Posts: 4,129	some bad news truck has an oil leak looks like it may be the rear main seal its dripping down the back of the oil pan. its only small, so nothing major to worry about. how bad is it gonna suck to fix this?

10-02-2006, 01:57 AM	#2
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Re: some bad news Not that bad... If you have a two piece seal, you just need to undo the engine mount bolts, and jack it up high enough to get the oil pan off. You then remove the rear main cap, use the seal from the bottom half to push the top half out, then stick some oil on the new one to lube it up, slide it in, making sure you center it, then lube up the bottom one, put it into the main cap, torque the maincap back down, put a single peice silicone pan gasket onto the oilpan, torque it down, drop the engine back down, then change your filter, put new oil in, and go. However, that said, if your truck has been sitting for a while, drive it for a few days and see if the leak goes away. Old seals dry up, and start leaking, but seal up once they've soaked in oil for a while. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

10-02-2006, 04:29 AM	#3
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Re: some bad news I would get a mirror (small telescopic kind) and look at the back of the intake end seal. Some other stuff to look at while your there. Distributor base gasket, oil sending unit / mechanical gauge tubing, valve covers, drain plug gasket, rear main area from under the truck. You should be able to see it with a flashlight to see if its wet with oil. Take the transmission inspection plate off and look at the crankshaft where the flexplate bolts up to it on the engine side. If that is dry it could be the oil pan gasket in the rear. I had a problem with my one piece oil pan gasket leaking in the front. This is because I didn't put silicone in the front of block. It is in the area where the timing chain cover and block meet. You need to have a put a ball of sealant there on both sides. As well as the rear where the rear main and oil pan meet. That is the only sealant you need with the one piece oil pan gasket from fel-pro. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

10-02-2006, 07:37 AM	#4
72C203503ONTHETREE Registered User Join Date: Apr 2004 Location: Grant, Alabama Posts: 504	Re: some bad news Shouldnt be too bad, maybe a a full days job if you rake your time. Biggest pain is getting the oil pan back on while trying to keep the gasket in one place and not moving it around. MIght want to replace the oil pump while you have the pan off if you have a lot of miles on it. New pumps are under 25 bucks and its cheap insurance. Also check a couple rod bearings, they are easy to replace while in the engine. __________________ 72 Chevy C20, SOLD (Dang it.) 09 Challanger RT six speed in all black. 74 Datsun 710 wagon, all 1.8 liters of screaming Datsun power. 73 C10 long bed, 350/350 combo, nice shape.



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