Blew a seal last night. Say what??

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Hevchev

Junior Member
Joined
Dec 19, 2018
Posts
5
Reaction score
4
Location
Montana
First Name
Nick
Truck Year
1978
Truck Model
K10
Engine Size
350
Hey all new to square bodies. I recently picked up a 78 k10.

After a short drive 5-10 minutes the bell housing and everything behind it is covered in oil from the wind. The oil pan stays pretty dry. It can lose a quart or more within a few minutes.

Any tips to confirm it is the rear main? Or any other spots to look at before I start the tear down.
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,853
Reaction score
5,646
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,76,70,48
Truck Model
Suburban k10, bonanza k10, k30, k20, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350, 350
Remove the inspection cover and look inside of the bellhousing. It should be coated with oil if it’s leaking that much, it should be dripping out honestly.

If it’s decently dry on the bottom it’ll be your valve cover gaskets or your intake gaskets.

Spray a bunch of degreaser over the motor and trans, of course be careful around stuff like the carb and distributor as well as with water wash it all down then run it and search everywhere to see where the oil starts leaking from.
 

Charlie

Mopar by Birth. Chevy by Choice.
Joined
Aug 2, 2017
Posts
1,837
Reaction score
912
Location
Euless, Texas
First Name
Don
Truck Year
1974
Truck Model
Cheyenne 10 LWB
Engine Size
350/TH350/AC/4 BBL Quadrajet
:welcome:
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,439
Reaction score
28,345
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Blew a seal... Reminds me of a song.

Seriously though, besides the rear main, the oil pressure sending unit up next to the distributor could be puking oil too.
 

Hevchev

Junior Member
Joined
Dec 19, 2018
Posts
5
Reaction score
4
Location
Montana
First Name
Nick
Truck Year
1978
Truck Model
K10
Engine Size
350
I will take a look at those things tomorrow.

Thanks guys
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,853
Reaction score
5,646
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,76,70,48
Truck Model
Suburban k10, bonanza k10, k30, k20, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350, 350
Or the distributor gasket even
 

Hevchev

Junior Member
Joined
Dec 19, 2018
Posts
5
Reaction score
4
Location
Montana
First Name
Nick
Truck Year
1978
Truck Model
K10
Engine Size
350
Haha good video haven’t seen that.

At least part of it is coming from the fuel pump that I recently replaced.

The pump came with two thin paper gaskets is there a better brand out there or rtv it?
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,439
Reaction score
28,345
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
The paper gaskets have always worked for me. When you replaced the pump, did you put the short bolt back in the hole on the front of the block? The one that you remove to use a longer bolt in the hole so the fuel pump pushrod doesn't fall out.
 

71RAT

Full Access Member
Joined
Jan 11, 2019
Posts
109
Reaction score
80
Location
Deerfield NH
First Name
Kirk
Truck Year
1983
Truck Model
K20 Scottsdale
Engine Size
461
Hey all new to square bodies. I recently picked up a 78 k10.

After a short drive 5-10 minutes the bell housing and everything behind it is covered in oil from the wind. The oil pan stays pretty dry. It can lose a quart or more within a few minutes.

Any tips to confirm it is the rear main? Or any other spots to look at before I start the tear down.

Oil pressure sensor, back of the block
 

Kyle89

Full Access Member
Joined
Jan 8, 2019
Posts
69
Reaction score
22
Location
Potosi missouri
First Name
Kyle
Truck Year
1984
Truck Model
C10
Engine Size
350
Welcome to the forum good luck with your problem... I had a 88 that it turned out to be the rear part of,the intake between the block and intake... Bought it from a guy he put a new intake on and didt have a proper seal and thought he blew the rear main... Bought the truck for 400 bucks put new intake gasket set on it and drive it for a year before selling
 

Forum statistics

Threads
44,162
Posts
950,643
Members
36,276
Latest member
2manysquares2care
Top