360 rear main

[Rowdy Bars]

I need some help I have a 360 la that I’ve rebuilt and it runs great but the problem is I’m fighting a leak it leaks like the rear main so I pulled the motor and installed a new one and it still dumps oil it leaks about a gallon in 30 miles I don’t know what to do

 

[skep419]

I need some help I have a 360 la that I’ve rebuilt and it runs great but the problem is I’m fighting a leak it leaks like the rear main so I pulled the motor and installed a new one and it still dumps oil it leaks about a gallon in 30 miles I don’t know what to do

360 rear main seal - Different PN for different years?
BS40651 felpro viton seal

 

[Rowdy Bars]

I have the Bs40651 seal in it

 

[skep419]

I have the Bs40651 seal in it

Lots of things that can leak back there that can look like rear main. What oil pan are you using? Possible cam plug, oil pressure sender, etc.

 

[Rowdy Bars]

So I have a stock 5 quart 318 pan out of a van on it and I don’t think it’s the cam plug because I can run around town all day with 75 psi of oil pressure and not leak that much oil when I get out on the highway and get it up in rpm then it leaks bad and it’s coming out of the inspection cover

 

[skep419]

So I have a stock 5 quart 318 pan out of a van on it and I don’t think it’s the cam plug because I can run around town all day with 75 psi of oil pressure and not leak that much oil when I get out on the highway and get it up in rpm then it leaks bad and it’s coming out of the inspection cover

Are you running a pcv valve?

Wait a second you can't run a 318 pan on a 360

 

[abodyjoe]

mine wasn't leaking as bad as yours. had the pan down twice, all the plugs behind the motor were dry. last time out we replaced the rear main with a different type. wasn't rubber. we also used an older (new) rubber piece of pan gasket at the rear of the pan. my buddy has a whole bag of them from over the years. it seemed to fit a bit better then the new felpeo on i had. not sure which it was but so far it seems to be fixed. not many miles on it yet though so I'm worried.

 

[Newbomb Turk]

If it is the main seal, you need to install the seal DRY into the block and cap.

Then look at how far the seal is sticking out of the block and cap.

It should be no more that .015 above the block and cap.

If it is you need to trim the seal down so you only have .0050-.0150 per side, and I’d rather be closer to .010 proud of the cap and block.

If the seal is out more than that, when you torque the cap down you have so much crush the seal goes out of round. That makes it leak.

 

[Newbomb Turk]

Are you running a pcv valve?

Wait a second you can't run a 318 pan on a 360

That is a problem isn’t it!!!

 

[Rowdy Bars]

Are you running a pcv valve?

Wait a second you can't run a 318 pan on a 360

It’s got aftermarket valve covers with big breathers and the 318 pan seems to fit fine

 

[Newbomb Turk]

It’s got aftermarket valve covers with big breathers and the 318 pan seems to fit fine

A 318 pan does NOT fit a 360. No wonder you have a leak.

Get the correct pan.

Unless you THINK you have a 318 pan and it’s really a 360 pan.

 

[Rowdy Bars]

How do you tell what pan it is

 

[Newbomb Turk]

How do you tell what pan it is

If it’s a stock pan there should be a number stamped into it. Post that number.

If it’s an aftermarket pan, what brand and part number is it?

 

[Rowdy Bars]

I can’t find the numbers on it but I’m pretty sure it’s a 318 pan

 

[junkyardhero]

pardon my lapse in clairvoyance (it's early! and i'm nocturnal!), but can you even fit the 318 pan on a 360? i thought that the rear was too chunky and the 318 pan won't even come close to tightening up.

i know you can go the other way with a 360 pan on a 318 and it'll pour oil.

 

[skep419]

It shouldn't fit, your 360 is either a 318 or your oil pan is off a 360 ¯\_(ツ)_/¯

 

[Rowdy Bars]

i don’t think the oil pan is leaking because it is coming out in the bell housing

 

[skep419]

i don’t think the oil pan is leaking because it is coming out in the bell housing

To not look into this would be an absolute mistake, but whatever you want to do sir.

 

[Rowdy Bars]

Ok a new pan is on the way

 

[skep419]

Ok a new pan is on the way

I'd check the block before ordering anything.

 

[413]

If it still leaks the same I doubt it's the rear main seal. While the pan is off get that HV oil pump outta there, no need to run around town at 75psi.

 

[AJ/FormS]

Leaking a gallon in 30 miles has to be obvious.
At 30 mph that is about
128oz/60 minutes= over 2 ounces per minute.

If it was me, I would pressurize the CC with a regulated air-supply, and see where it comes out.

 

[Professor Fate]

pardon my lapse in clairvoyance (it's early! and i'm nocturnal!), but can you even fit the 318 pan on a 360? i thought that the rear was too chunky and the 318 pan won't even come close to tightening up.

i know you can go the other way with a 360 pan on a 318 and it'll pour oil.

It shouldn't fit, your 360 is either a 318 or your oil pan is off a 360 ¯\_(ツ)_/¯

Other way around, boys. (look close at skep's pan pics)
360 uses a smaller diameter rear pan seal. It's a 360 pan that won't fit a 318 block.
If you put a 318 pan on a 360, you'll have a 1/2" gap in there and oil will just pour out of the rear of the pan all over the back of the engine and bellhousing.
The pan will bolt up, but you may as well just leave the drain plug out- you'll lose that much oil.

 

[67Dart273]

Is this a MAGNUM or an LA. You really should call an LA a 360 and a magnum a 5.9 just to be clear

MAGNUM 5.2 and 5.9s us the SAME PAN

You can use a 360LA pan on a 360LA, you can sort of use them on a 5.2 or 5.9 Magnum

You can ONLY use a 318 LA pan on 273/318/340 LA engines. NOT magnum engines.

The difference is obvious. On a 273/318/340LA pan, the half moon cutouts for the front and rear pan seals appear about the same. On a 360LA pan the rear half moon cutout is obviously SMALLER.

 

[Rowdy Bars]

If it still leaks the same I doubt it's the rear main seal. While the pan is off get that HV oil pump outta there, no need to run around town at 75psi.

It has a new factory pump in it