Engine - rear oil leak

[2000StreetRod]

Part of the reason I decided to pull my 2000 SOHC V6 was to fix a very slow oil leak at the rear of the engine. I just assumed that it was the crankshaft rear main seal that was leaking since there is over 150,000 miles on the odometer. When I searched the forum I learned that there are three possible sources of leaks at the rear of the engine. I immediately eliminated the lower oil pan gasket since the oil stains were above where the lower pan mounts to the upper pan/reinforcement structure. After pulling the engine and examining the rear of the block I can't tell from the stains if the rear main seal is leaking or if the gasket between the reinforcement structure and the block is leaking but I will replace both.

From my forum search I also learned that many members who replaced their rear main seal were not satisfied with the results. In some cases the replacement seals immediately leaked and in others leaking began within a few thousand miles.

My Haynes manual is rather vague about the rear main seal replacement process. It mentions screwing a couple of sheet metal screws into the old seal, pulling it out, and driving in the old one.

Some posts on the forum indicate there are different types of seals and one of the Ford ones requires a special tool. There is also mention of the importance of how far to drive in the seal. One member mentions a special Ford seal kit that includes two seals of different diameters.

The photo below shows two FelPro seals listed on RockAuto for my SOHC engine. They don't appear to be equivalent.

I could not find an adequate step-by-step replacement procedure on the forum.

Please share your knowledge and provide me assistance in how to proceed to acquire and install a long lasting, reliable seal on the first attempt.

 

[2000StreetRod]

OEM rear main seal

Below is a photo of the Ford OEM PN F5TZ6701A that I found on usaallparts.com for 1991-2000 OHV V6 and 1997-2009 SOHC V6.

It looks equivalent to the second FelPro seal in the previous post. So far, I have not found any Ford seal kit listing.

 

[Anime]

Ford's 4.0L rear seals do leak for sure. So much that Ford even makes the kit to fix it.

You'll want not just the seal itself, but the sleeve designed to house the seal, which makes for a more leakproof setup, if installed correctly.

Price at the dealer is a little much, but you can PM forum member FORDSVTPARTS for discount pricing on the OEM part. The aftermarket also offers several seal/sleeve kits or the seals and sleeves seperately, plus the sleeve install tool for the job.

 

[2000StreetRod]

Fel-Pro Rear Seal Kit

Today I ordered the Fel-Pro crankshaft seal kit part number BS40619 from RockAuto. If anyone has tips on removing or installing the rear main seal I'd like to hear them.

 

[Anime]

If you can get a seal remover (long L-shaped tool with a sharp prong at the end for piercing and grabbing the seal, useful if force is needed), or some kind of sharp awl, it can be easier to pierce and tug at the seal and pull it out without risking any damage to the seal surface. It can take some time without the right tool, but it's worth doing it slowly and completely destroying the old seal rather than risk even the slightest scratch on the sealing surface.

After the old seal is out, clean up the surface, prepare for installing the sleeve according to the instructions (using any sealant if supplied or mentioned), then install the sleeve CAREFULLY with the sleeve install tool. Then prepare the new seal with sealant/oil/or assembly lube, being sure to put some oil or lube film on the inner surface, since otherwise the seal will burn up when the engine is started with the new seal and a dry surface. Use either the sleeve install tool (if it fits) or the correct tool for seating and banging on new seals. Sometimes the right diameter pipe with some duct tape around the end works ok for circular seals, but you'll get a lot more control with a seal install tool that's the right size, and with the screw-on center piece that lets you bang it on evenly without having to tap tap tap around the edge 50 times.

Most importantly, read any instructions that come with the seal/sleeve itself, many times they vary slightly from general instructions and have their own sealant or process they came up with for a leak-free seal.

It's worth spending the dough for the right stuff you need to install it, waiting a few days to get everything together, or the trip to autozone to borrow any tools.
It REALLY sucks to put it all back together and find even a minor leak.

 

[mrb09c]

Part of the reason I decided to pull my 2000 SOHC V6 was to fix a very slow oil leak at the rear of the engine. I just assumed that it was the crankshaft rear main seal that was leaking since there is over 150,000 miles on the odometer. When I searched the forum I learned that there are three possible sources of leaks at the rear of the engine. I immediately eliminated the lower oil pan gasket since the oil stains were above where the lower pan mounts to the upper pan/reinforcement structure. After pulling the engine and examining the rear of the block I can't tell from the stains if the rear main seal is leaking or if the gasket between the reinforcement structure and the block is leaking but I will replace both.

When you say 'gasket between the reinforcement structure and the block', do you mean the upper oil pan gasket or do you actually mean the head gasket?

 

[2000StreetRod]

When you say 'gasket between the reinforcement structure and the block', do you mean the upper oil pan gasket or do you actually mean the head gasket?

Not the head gasket.

 

[Auspuff]

I know this an old thread but it come up high when I was searching for information related to this so an update might be useful.

The photo below shows two FelPro seals listed on RockAuto for my SOHC engine. They don't appear to be equivalent.

The first one looks like
FEL-PRO BS40647 Rear Main Seal Set, Rear; Type: Rear Main Seal Set; PTFE Rubber; One-piece

The second one looks like
FEL-PRO BS40619 {#5TZ6701A} Rear Main Seal Set, Rear; Type: Rear Main Seal Set; Wear sleeve incl; Rubber; One-piece

I guess the BS40647 is the seal without a wear sleeve? Odd though, it's more expensive than the one with the wear sleeve.

I have the BS40619 ready for installation, it has the wear sleeve included.

Rockauto also has Mahle JV1618 which looks the same and description says "Wear Sleeve Included"

Original Ford part number for seal with wear sleeve is 5TZ-6701-A, about $50 from one of the online Ford part websites. Versus $8-$16 for Mahle or Fel-Pro.

@StreetRod, is that Fel-Pro seal you installed still holding up ok?

 

[2000StreetRod]

The PTFE rubber is more expensive to manufacture. I suspect it lasts longer than the normal rubber but I avoided it because it is harder and more likely to leak on a worn crankshaft. I did not install the sleeve. As far as I know my seal is not leaking. However, I wished that I had replaced the valve cover gaskets or used a sealant when I reused the ones on the engine. I had a leak on the driver side initially and had to keep tightening the bolts to stop it.

 

[roscoe 0202]

if you oil a Teflon [ptfe] seal it will leak should be installed on clean dry shaft. cummins cat Detroit all use ptfe seals.
roscoe