REAR MAIN LEAK

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mbc1967

New Member

Dec 31, 2006

19

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0

Great State of Texas

Apr 19, 2007

#1

• Apr 19, 2007

• #1

Hi all. Just got my 351W running and thought I did everything right. WHAT? The rear seal is leaking. The oil pan has no oil on it so I know it is not from there. The oil is running down the engine side of the block plate. Drips just a little when it is running. Drips about the size of a half dollar when you stop the engine. If any of you guys have had this problem let me know where to start. Thanks, Mike.

 

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BB1966

New Member

Dec 1, 2004

297

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Beaufort , NC USA!!!!

Apr 19, 2007

#2

• Apr 19, 2007

• #2

Make sure the PCV hose is hooked up and not sucked together.

 

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mbc1967

New Member

Dec 31, 2006

19

0

0

Great State of Texas

Apr 19, 2007

#3

• Apr 19, 2007

• #3

BB1966 said:

Make sure the PCV hose is hooked up and not sucked together.

Click to expand...

I am not running a pcv just a breather. Is that bad?

 

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BB1966

New Member

Dec 1, 2004

297

1

0

Beaufort , NC USA!!!!

Apr 19, 2007

#4

• Apr 19, 2007

• #4

All depends if the breather is doing its job,new engine could have a little more base pressure. The little spring could have popped off the inside of the seal.

 

CraigMBA

New Member

Mar 24, 2007

783

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Orange, CA

Apr 19, 2007

#5

• Apr 19, 2007

• #5

mbc1967 said:

I am not running a pcv just a breather. Is that bad?

Click to expand...

Yes. Two breathers (one in each valve cover) is okay but one is bad news.

 

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mbc1967

New Member

Dec 31, 2006

19

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0

Great State of Texas

Apr 22, 2007

#6

• Apr 22, 2007

• #6

Well I put a PCV valve on and a breather on other side and it's still leaking. What would you guys do? I am thinking pulling the engine and see whats going on. Thanks Mike

 

65FBE2

Member

Mar 8, 2007

283

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17

Minnasnowta

Apr 22, 2007

#7

• Apr 22, 2007

• #7

I have had the same problem on my 347! spoke with my engine builder and he said that once in a while the cast in grove for the rear main is so out of round that you need to place a .01 shim under the seal. This is on a two piece seal block. It worked for me

 

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TOM B

20+ Year Stangneter

Nov 15, 2002

872

1

16

Harrisburg Pa

Apr 22, 2007

#8

• Apr 22, 2007

• #8

all ford cranks have OPEN holes in the rear crankshaft where the flywheel bolt on, You MUST use a sealer on the threads or you Will have a leak

 

dennis112

15 Year Member

May 15, 2005

1,561

36

79

Amish Wonderland of Central PA.

Apr 22, 2007

#9

• Apr 22, 2007

• #9

TOM B said:

all ford cranks have OPEN holes in the rear crankshaft where the flywheel bolt on, You MUST use a sealer on the threads or you Will have a leak

Click to expand...

351w's have blind bolt holes that don't use a sealer.

I suggest checking the rear of the intake manifold and the valve covers. They often cause what appears to be a rear mains seal leak.

Other possible causes is a loose oil galley plug or the rear camshaft core plug.

 

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mbc1967

New Member

Dec 31, 2006

19

0

0

Great State of Texas

Apr 22, 2007

#10

• Apr 22, 2007

• #10

65FBE2 said:

I have had the same problem on my 347! spoke with my engine builder and he said that once in a while the cast in grove for the rear main is so out of round that you need to place a .01 shim under the seal. This is on a two piece seal block. It worked for me

Click to expand...

Were did you get your shim? Just in case.

 

HookandLadder

Founding Member

Feb 17, 2001

261

0

17

St Louis

Apr 23, 2007

#11

• Apr 23, 2007

• #11

rear of the intake or valve covers. Do this before you yank it apart. Try some engine dye to isolate the leak spot.

 

dennis112

15 Year Member

May 15, 2005

1,561

36

79

Amish Wonderland of Central PA.

Apr 24, 2007

#12

• Apr 24, 2007

• #12

HookandLadder said:

rear of the intake or valve covers. Do this before you yank it apart. Try some engine dye to isolate the leak spot.

Click to expand...

Who stock engine dye? Will Napa have it?

 

Rusty67

20+ Year Stangneter

Dec 3, 2002

3,749

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109

LA, CA

Apr 24, 2007

#13

• Apr 24, 2007

• #13

Ya, thats something I'd like to know as well.