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Leaking Rear Main Seal.Crankcase pressure?

  • Thread starter Thread starter demononwheels
  • Start date Start date Feb 12, 2007

demononwheels

New Member
Jul 1, 2006
10
0
1
Texas
Feb 12, 2007
#1
  • Feb 12, 2007
  • #1
My rear main seal has been leaking for a while. The engine has around 6000 miles on it. So while the clutch was being replaced today, the rear main seal was also replaced. My car was delivered to my house today while I was at work. When I drove up to my house, I notice a spot of oil underneth the car. After being replace it still leaks. I think I have to much crankcase pressure. What can I do ? I have one breather on the passenger side valve cover. Every once and a while the dip stick will be pushed up from the pressure. Oh yea, I running around 14 psi of boost.
But not today. Not with the new clutch. Its a 1993 ford Mustang. Any suggestions? I'm thinking I have to live with the oil leak.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Feb 13, 2007
#2
  • Feb 13, 2007
  • #2
Can you add yet another breather?
 

gtxracing

New Member
Feb 5, 2007
49
0
0
Feb 13, 2007
#3
  • Feb 13, 2007
  • #3
It will be more than a breather issue if he's constantly getting crankcase pressure and buying breathers to cover the rest of the year won't help... Blowby, lower your boost, it could be multiple issues with crankcase problems. Hell replace the pistons with some new Keith Black Hyper. Pistons and have a good day. I did that to mine and I had no issues since. I started finding oil all over my pipes, valve covers, on the tranny, I say WTF??? so I did that and no more since
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Feb 13, 2007
#4
  • Feb 13, 2007
  • #4
With nearly a bar of boost, I'd expect some blowby (on an otherwise unknown spec'd motor). Very adequate crankcase ventillation would be requisite (I saw no desire to turn down boost).

I would want to do a leakdown test before assuming it was a ring-seal issue. And if motor work was done (shouldnt be needed if your mill has 6K miles on it, right), I'd go with forged slugs. The looser cold-bore-fit is more than offset by the metallurgical benefits with so much boost IMHO.
 

vristang

15 Year Member
Mar 31, 2005
4,933
101
124
Seattle
Feb 13, 2007
#5
  • Feb 13, 2007
  • #5
Don't go rebuilding the motor just yet.
Find out what is wrong before replacing parts...

What is the current pcv setup on the car?
Is the Throttle Body/Valve Cover hose still in the stock location?
Is the pcv still in its stock configuration?

Could a really simple fix,
jason
 

joeyd0730

Member
May 22, 2005
130
0
16
queens, ny
Feb 13, 2007
#6
  • Feb 13, 2007
  • #6
i had a similar problem as posted in the past. turned out to be bad intake gasket. exhaust from the egr ports on the head was blowing into the valley due to the wrong gasket being used.
 
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