• Welcome to the new SAOCA website. Already a member? Simply click Log In/Sign Up up and to the right and use your same username and password from the old site. If you've forgotten your password, please send an email to membership@sunbeamalpine.org for assistance.

    If you're new here, click Log In/Sign Up and enter your information. We'll approve your account as quickly as possible, typically in about 24 hours. If it takes longer, you were probably caught in our spam/scam filter.

    Enjoy.

Excessive Oil Leak at Shutdown

Bill Blue

Platinum Level Sponsor
We recently purchased a 69 Fastback. It has a 1725 engine. After operating long enough to bring the temperature gauge into the normal range, it leaks 6-8 oz of oil out of the rear main when the engine is stopped. Changing oil filters stopped the excessive oil leak. The difference - the old oil filter has a drainback valve, the new one does not.

I have no idea why this is happening. I am posting to see how common this problem might be and if anyone knows why the drainback valve would cause it. BTW the old filter is a PH253 (not branded) the new one is a Wix 51410.

Bill
 

RootesRacer

Donation Time
Sounds like perhaps the cam plug (behind the flywheel) might be leaking or even missing. There are some gallery plugs around the block too, not sure if there are any in the rear area though.

Edit, I just looked at a 1725 block and yes, there is a 1/4 npt plug in the oil gallery in the rear too.
 
Last edited:

Bill Blue

Platinum Level Sponsor
Sounds like perhaps the cam plug (behind the flywheel) might be leaking or even missing. There are some gallery plugs around the block too, not sure if there are any in the rear area though.

Edit, I just looked at a 1725 block and yes, there is a 1/4 npt plug in the oil gallery in the rear too.
Why it does not leak while the engine is running?
Bill
 

RootesRacer

Donation Time
Dont know but you can test this possibility by removing the flywheel panel cover from the hellhousing and get a light and mirror up there to see if its weeping from the crank flange or higher up (cam plug) or to the side (gallery plug).
 

RootesRacer

Donation Time
Also keep in mind the crank is a scroll seal and if its not spinning, it wont prevent oil splash from getting past the scroll.
 

Barry

Diamond Level Sponsor
Have been thinking about why you would have significant leakage at the back of the engine after shut-down when using an oil filter WITH an anti-drain back valve, but not when using an oil filter WITHOUT an anti-drain back valve.

With the upside down oil filter mounting position on the 1725 engine, there are two ways that the oil in the filter can drain down into the engine. One way is through the center "outlet" of the filter which connects to the engine oil gallery. The other way is through the filter "inlet" which is the outer ring of the filter that has multiple holes and which connects to the oil pump. If the filter has an anti-drain back valve, it is located just inside the outer ring / holes and it is supposed to prevent oil from draining back through the oil pump.

With an effective anti-drain back valve, the only place for the hot oil to drain is into the oil gallery which connects to the rear main bearing which is adjacent to the rear labyrinth seal. With no anti-drain back valve and a "loose" oil pump, the hot oil can probably drain through the oil pump pretty quickly which would reduce the tendency to go through the oil gallery to the rear main bearing.

Just my SWAG. Maybe right, maybe not. Seems to me that something has to be wack-a-doodle with the rear main bearing housing or the labyrinth seal for 6-8 ounces of oil to leak out quickly without any oil pressure.
 

husky drvr

Platinum Level Sponsor
With an effective anti-drain back valve, the only place for the hot oil to drain is into the oil gallery which connects to the rear main bearing which is adjacent to the rear labyrinth seal. With no anti-drain back valve and a "loose" oil pump, the hot oil can probably drain through the oil pump pretty quickly which would reduce the tendency to go through the oil gallery to the rear main bearing.

Just my SWAG. Maybe right, maybe not. Seems to me that something has to be wack-a-doodle with the rear main bearing housing or the labyrinth seal for 6-8 ounces of oil to leak out quickly without any oil pressure.

Barry,

Don't forget that the pressurized oil gallery is also connected to the cam bearings.
 

Barry

Diamond Level Sponsor
Barry,

Don't forget that the pressurized oil gallery is also connected to the cam bearings.



I did not forget, but I don't see any way for the cam bearings to leak oil out the back of the block after the engine is shut down and not leak when the engine is running.
 
Last edited:

RootesRooter

Donation Time
Where is the "panel cover?"

Dont know but you can test this possibility by removing the flywheel panel cover from the hellhousing and get a light and mirror up there to see if its weeping from the crank flange or higher up (cam plug) or to the side (gallery plug).
 

Mike O'D

Gold Level Sponsor
Does an anti-drainback valve actually keep the oil in the filter, or does it slowly drain out through the normal path through the bearings, etc. when the engine is shut off? I changed my oil over the weekend and there was only a very small amount (1/2 oz or less) of oil that ran out when the filter was removed. Filter had the valve - didn't appear to have any oil inside it.
 

Bill Blue

Platinum Level Sponsor
Does an anti-drainback valve actually keep the oil in the filter, or does it slowly drain out through the normal path through the bearings, etc. when the engine is shut off? I changed my oil over the weekend and there was only a very small amount (1/2 oz or less) of oil that ran out when the filter was removed. Filter had the valve - didn't appear to have any oil inside it.
Very good question. A person has to question the whole idea of drainback valves. You really need it when the car sets for days without being started. That is exactly when it will do no good.
In my case, I know where the oil trapped in the filter goes. When I removed the old filter it leaked less than a tablespoon of oil. I knew immediately what to expect with the new filter. Does your car leave a very large oil spot? This car left an overnight spot that was approximately 14" x 16" on concrete.

Bill
 

65beam

Donation Time
Does an anti-drainback valve actually keep the oil in the filter, or does it slowly drain out through the normal path through the bearings, etc. when the engine is shut off? I changed my oil over the weekend and there was only a very small amount (1/2 oz or less) of oil that ran out when the filter was removed. Filter had the valve - didn't appear to have any oil inside it.
If you still have the old filter I would suggest that you cut the base off and check out the inner workings. If you really want an education buy the cheapest Fram and a Wix like Bill did. In my early days as a Valvoline rep we carried a filter cutter to show customers the difference between various brands of filters. Seeing the differences is worth a thousand words.
 

Bill Blue

Platinum Level Sponsor
If you still have the old filter I would suggest that you cut the base off and check out the inner workings. If you really want an education buy the cheapest Fram and a Wix like Bill did. In my early days as a Valvoline rep we carried a filter cutter to show customers the difference between various brands of filters. Seeing the differences is worth a thousand words.
Sorry Bob, but I'd be a lost ball in the tall grass. No clue what I'm looking at or what I should find. If you want, I can send it to you for inspection.
Bill
 

65beam

Donation Time
Bill,
Filters contain what is called a "base plate". This is what the filter unit sets on at the base of the filter. You'll find some are cardboard while other companies use a metal base plate. There is also a bypass valve in case the filter gets plugged. There are noticeable differences in the filter paper, etc. Just cut the filter cannister near the base with the threads. You can use a hack saw to cut the filter open.
 

RootesRacer

Donation Time
Where is the "panel cover?"
Its the the panel that covers the lower portion of the bellhousing on the steel sump 1500, 1600 and 1725 engines.

The alloy sump used on some arrow 1725 would replace the need for the panel cover (and make inspection impossible) but I have no idea if Bills engine has the alloy sump.
 

65beam

Donation Time
Its the the panel that covers the lower portion of the bellhousing on the steel sump 1500, 1600 and 1725 engines.

The alloy sump used on some arrow 1725 would replace the need for the panel cover (and make inspection impossible) but I have no idea if Bills engine has the alloy sump.
The aluminum sump was used on only the GT. Bill's car has the steel sump pan.
 

RootesRooter

Donation Time
Oye! I've had the aluminum pan for so long I forgot about the standard cover plate. The idea of scoping out the back of the block with a camera sounds great. Has anyone posted video of this procedure?
 
Last edited:

Bill Blue

Platinum Level Sponsor
Bill,
Filters contain what is called a "base plate". This is what the filter unit sets on at the base of the filter. You'll find some are cardboard while other companies use a metal base plate. There is also a bypass valve in case the filter gets plugged. There are noticeable differences in the filter paper, etc. Just cut the filter cannister near the base with the threads. You can use a hack saw to cut the filter open.
Bob, all that is well and good. What would I be looking for that would cause the massive oil leak? I'm guessing the lack of a rigid base plate would cause drainback valve failure, not a rear main oil leak.
Bill
 

65beam

Donation Time
Bill,
I just thought you might want to know what you're dealing with. I tend to take things apart to see how they work and how they're made. I've never seen a filter cause an oil leak in another part of the engine so I'm stumped. I have seen oil filter gaskets that leak due to various reasons.
 

Bill Blue

Platinum Level Sponsor
Bill,
I just thought you might want to know what you're dealing with. I tend to take things apart to see how they work and how they're made. I've never seen a filter cause an oil leak in another part of the engine so I'm stumped. I have seen oil filter gaskets that leak due to various reasons.
Like the old gasket stuck to the block and you did not notice? Been there, done that. A good way to dispense 3 qts of oil into the atmosphere in a few minutes.

Bill
 
Top