Make payments with PayPal - it's fast, free and secure! registry | CVN on Facebook | tech | news | email login Click here for ADTR! Make payments with PayPal - it's fast, free and secure!

Welcome to CVN - Your Panther platform headquarters!

Custom Search

Topic Options
#1776254 - 05/27/09 04:25 PM A sad day: rear main engine seal leak
Seffywuff Offline

Registered: 04/14/08
Posts: 53
Loc: Oklahoma City
I decided to get under my car today and try to find out where my oil leaking was coming from. I only go through about half a quart per oil change, so I was never very concerned. I'm pretty sure it's the rear main seal. It's coming form a small gap from where I believe the engine and transmission meet. It's right above a metal bar who's function I am unaware of, but which goes from left to right across the vehicle, as does the slot where the oil is coming from.

I hear you have to either pull the engine or transmission to get at the rear main, so I think it'd probably be best just to let it leak until I get the transmission rebuilt. It lasted 135 thousand miles, so I guess it's not too bad, though, I don't know exactly how long it's been leaking. Should I bother with any of those seal repair additives, or just let it go?

Thanks for reading.
1987 Grand Marquis 2 door, 110k

Stock 1989 LTD Crown Victoria. 125 thousand miles and counting. - Sold.

#1776278 - 05/27/09 04:42 PM Re: A sad day: rear main engine seal leak [Re: Seffywuff]
JeffBoudah Offline


Registered: 06/05/03
Posts: 8911
Loc: Holland,MI
Check the rear intake manifold lower gasket. This has a tendency to blow out over the years, making it look suspiciously like a rear main leak. Run your hand back along as if you were attempting to change out the PCV valve, and see if the back of the block is covered in oil above the rear main.

1979 LTD 2-Door, 64k miles - Restomod W.I.P.
1979 LTD Wagon, 120k miles - Ratrod W.I.P.
2003 Exploder XLT 155k miles - Daily Driver

#1776348 - 05/27/09 06:05 PM Re: A sad day: rear main engine seal leak [Re: JeffBoudah]
mrltd Offline
Over the Hill

Registered: 01/09/03
Posts: 1356
Loc: MD
more than likely a large part of it is the valve covers and/or intake manifold. Oil leaks are also made worse by non functioning PCV systems. The usual culprit with the PCV is the screen underneath it. (lots of posts on the PCV screen)

#1776386 - 05/27/09 07:52 PM Re: A sad day: rear main engine seal leak [Re: mrltd]
TheBlunderbuss Offline
Over the Hill

Registered: 02/24/06
Posts: 1506
Recap the other possibilities: Upper intake manifold gaskets, valve cover gaskets, PCV valve/seating area, or oil pan gasket. Fear not!

Quick rundown of the screen: Often called a "crankcase breather filter," this will run you from $3-7 and could be had at Autozone.
Extraction is easy. It involves a wood screw of at least 6" so you can grip it. You don't need much thread on it. $1 at hardware stores.
One thread is really all you need to screw into the mesh, and the whole thing should slide out.
Install the new one by pushing it in with the PCV grommet.
02/88 LTD Crown Victoria - 860 miles (hehe)
Don't forget that Throttle valve cable clip update!

#1777563 - 05/28/09 10:23 PM Re: A sad day: rear main engine seal leak [Re: TheBlunderbuss]
Unforgiven Offline

Over the Hill

Registered: 01/29/02
Posts: 2128
Loc: West Tennessee
If it is the back of the intake its really not hard at all to fix... As long as you have the tool to disconnect the fuel line... I had mine done in my driveway in an afternoon on my 87.
Former owner of: 1989 LTD Crown Victoria p73, 1989 LTD Crown Victoria p72, 1987 LTD Crown Victoria p72, 1997 Crown Victoria p71

Current ride: 2002 Eddie Bauer Expedition

#1778080 - 05/29/09 01:21 PM Re: A sad day: rear main engine seal leak [Re: Unforgiven]
Dave58 Offline

Registered: 09/08/08
Posts: 37
Loc: Colorado, USA
My '87 CV with 5.0L had the same rear of engine drip. I replaced the valve cover gaskets and now it is perfectly dry.

#1784964 - 06/07/09 10:08 PM Re: A sad day: rear main engine seal leak [Re: Dave58]
BillB Offline

Registered: 10/11/06
Posts: 153
Loc: Revere MA
I agree with others--may not be a big problem.
my 87CV had similar oil leak.
Left side valve cover bolts were so loose did not need a ratchet to tighten--theres one bolt way in back cant see it but its there waiting to be tightened along with the other 4 or 5.

and check the right side vlv. cover too--for both L and R covers, at least two of these bolts are hard to see
87F CV P73
91 Merc GM

#1785247 - 06/08/09 10:34 AM Re: A sad day: rear main engine seal leak [Re: BillB]
Jeff2 Offline
Over the Hill

Registered: 08/11/08
Posts: 4881
Loc: Cincinnati, Ohio
My biggest oil leak turned out to be my oil pressure switch. The switch was cheap, but I had to buy a big socket to replace it and the socket cost more than the switch!
1991 Crown Victoria LX - something like 154k miles (odometer gears have been broken for some time now)

#1787826 - 06/11/09 11:13 AM Re: A sad day: rear main engine seal leak [Re: Jeff2]
88grandmarq Offline

4R70W rebuilder

Registered: 07/10/02
Posts: 5991
Loc: North Georgia
80% of the time engine oil leaks are caused by a clogged PCV screen.

take some engine cleaner, apply it and pressure wash everything as best you can. then replace the PCV valve, grommet and screen.
If your leak continues, you can at least get a better idea where its coming from.

NOT very common for rear main seals to leak on these motors, more likly the valve covers or intake manifold gasket.
2003 Lincoln Town Car Signature - 3.27 RAR, dual exhaust and J-mod - SOLD 09/2011
89 Crown Victoria LX- HPP Box - SOLD 09/2010
88 Grand Marquis LS - The original - Totaled 5/2006

I rebuild AOD/AODE/4R70W/4R75E Transmissions, check out my Facebook page for my latest project; https://www.facebook.com/pages/North-Georgia-Transmission-Auto-Repair/348414635312478


Moderator:  88grandmarq, MAFpilot 
Who's Online
9 registered (brake.turn.gas, GRC, CVJPMG, flyer2359x, 2000-CVPI, ford05), 60 Guests and 75 Spiders online.
Key: Admin, Global Mod, Mod
Shout Box

Email Login
EMail Login Name
 New users, sign up!
Top Posters (30 Days)
a_d_a_m 269
BigMerc96 235
s33k3r 209
Chaplian 174
Moby_Vic 142
98BoatCaptain 135
BigNSlow 115
Black_Sunshine 112
2000-CVPI 111
Blakat 110
Member Spotlight
Member Since: 04/14/05
Posts: 7801

Copyright 2000-2015 by Crownvic.net and Steve Spaulding. All Rights Reserved.
The photographs, graphics and data contained in this Web site are the properties of the contributors, or Crownvic.net and may not be used without expressed written consent.
Crownvic.net is not affiliated with the Ford motor company.

Happily consuming the fuel saved by Prius owners!