Excessive Oil Leak at Shutdown

[DanR]

I have been reading along as this discussion has taken several directions. I am stumped as to the cause for the leakage.

If the engine was recently rebuilt (as defined earlier) did the PO have such a problem? Has he been contacted to determine if so or not?

If he did have some sort of leakage, even a minor one, would appear some failure on the Mechanic to correct during
the rebuild. If so the best solution is the take down the engine and put back together.

That would be something I'm sure Mr Bill is not looking forward to having to entertain.

 

[Bill Blue]

The PO had the engine rebuilt because it had seized after 30 some years in storage. He drove it about 130 miles, said he had not noticed any large oil leaks.

Bill

 

[65beam]

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

Yep, you're right. Several years back I had one of my trucks that was pulling a tank full of anti freeze when the filter gasket blew. He was on I 90 south of Chicago and the fire created a small traffic jam at 6:30 A.M.

 

[65beam]

It's possible that the leak is at the back of the cam or the oil galley plug at the back of the engine leaks.

 

[Bill Blue]

No it isn't. If it was a plug leaking it would leak most (instead of of not at all) when the engine is running.

Bill

 

[Mike O'D]

Bill, to answer your question, I don't have any rear main seal leaks either during operation or after shut-down. Freshly rebuilt 1725.

 

[nsbluenose]

65Beam,
What oil filter do you suggest. I use either a Mobil 1 or a K&N.
Thanks, nsbluenose

 

[RootesRacer]

No it isn't. If it was a plug leaking it would leak most (instead of of not at all) when the engine is running.

Bill

But it is leaking somewhere for some reason. It wouldnt be the first time something that was "impossible" suddenly became a reality. Get in there with a mirror or scope and detect where the oil is coming from, then we can pontificate on the why.

There are 5 likely locations for oil on that engine to look like it came from the rear main.
1) The crankshaft
2) The Cam sealing disc
3) Rear oil gallery plug
4) Valve cover gasket leaking onto the real and down the block/bellhousing
5) Leaking PCV hose (some arrow 1725 engines dont seem to have this hose, they have a side cover without a vent tube)

 

[DanR]

said he had not noticed any large oil leaks.

What would he say is a large oil leak?

Did he have "any" oil leaks?

 

[Bill Blue]

As closely as I can recall, he said he had not noticed any oil leaks. I gave him the benefit of the doubt and figured he ignored any normal LBC spots left on the floor.
Bill

 

[Bill Blue]

But it is leaking somewhere for some reason. It wouldnt be the first time something that was "impossible" suddenly became a reality. Get in there with a mirror or scope and detect where the oil is coming from, then we can pontificate on the why.

There are 5 likely locations for oil on that engine to look like it came from the rear main.
1) The crankshaft
2) The Cam sealing disc
3) Rear oil gallery plug
4) Valve cover gasket leaking onto the real and down the block/bellhousing
5) Leaking PCV hose (some arrow 1725 engines dont seem to have this hose, they have a side cover without a vent tube)

How do you relate causes 4) and 5) to oil filter drainback?
It seems to me this is a lot of work for no reason. I know the leak is on the rear of the engine. The engine will have to be pulled in order to determine exact cause and make a repair. If, after a few days work, I discover there is a magic hole that only leaks under zero pressure, the engine has to be pulled in order to make a repair.

What has been gained?

Bill

 

[pruyter]

What you could do, as suggested before in a former posting, is removing the panel that covers the lower part of the bellhouse and then use an inspection lamp (or better an inspection camera) in order to find out if and if so where the oil is coming from i.e. the cam cover or the oil gallery plug. The crankshaft can be checked without using such a device.

Regards,

Peter

 

[65beam]

How do you relate causes 4) and 5) to oil filter drainback?
It seems to me this is a lot of work for no reason. I know the leak is on the rear of the engine. The engine will have to be pulled in order to determine exact cause and make a repair. If, after a few days work, I discover there is a magic hole that only leaks under zero pressure, the engine has to be pulled in order to make a repair.

What has been gained?

Bill

Bill,
The engine does not have to come out. The transmission could be pulled out along with the fly wheel / clutch assembly. Then you would have a clear view of the engine block and with the added space of the trans tunnel versus the series Alpine you or who ever is working on it would have room to make repairs if the cam plug or oil galley plug is leaking. FYI, The valve cover used these engines require the use of the thick cork valve cover gasket. The paper gasket won't begin to seal and with the tilt of the engine both to the side and the rear of the engine being lower the oil may be leaking because of having next to no gasket. Have you checked the valve cover gasket? I have several new gaskets if needed.

 

[RootesRacer]

How do you relate causes 4) and 5) to oil filter drainback?
It seems to me this is a lot of work for no reason. I know the leak is on the rear of the engine. The engine will have to be pulled in order to determine exact cause and make a repair. If, after a few days work, I discover there is a magic hole that only leaks under zero pressure, the engine has to be pulled in order to make a repair.

What has been gained?

Bill

I can think of some scenarios where both the crank and the cam plug would leak with very low oil pressure (drainback conditions) with the engine not running. The cam plug could act like a diaphragm with crankcase pressure and seal (for the most part), while leaking with no crankcase pressure.
I dont think you have much to lose performing the inspection and you shouldnt have to do much more than jack up the car, remove the panel and take a gander with a light, mirror or a scope.

 

[RootesRacer]

Also, if the anti-drainback fails, the cam and crank bearings will weep the filter oil until the oil head is at the same level as the highest bearing clearance point. The cam bearings could weep onto the crank scroll and cause the real to leak. This would be even more likley with the car parked slightly uphill.

 

[DanR]

I found this article on oil filters if anyone may be interested:

http://www.minimopar.net/oilfilters/index.html

 

[todd reid]

Thanks Dan very interesting article! My uncle advised me many years ago to buy inexpensive oil and a purolator filter, and to use the money I saved to cut the change interval in half. I have modified that slightly over the years, but the main point is big buck high tech oil and filters get dirty just like inexpensive ones so get the dirty stuff out of there. I maintain all the cars in our extended family (currently 8) and so far so good.

 

[65beam]

Thanks Dan very interesting article! My uncle advised me many years ago to buy inexpensive oil and a purolator filter, and to use the money I saved to cut the change interval in half. I have modified that slightly over the years, but the main point is big buck high tech oil and filters get dirty just like inexpensive ones so get the dirty stuff out of there. I maintain all the cars in our extended family (currently 8) and so far so good.

The additive package in engine oils is engineered to hold contaminants such as soot and other by products of combustion in suspension and the filter traps some of the byproducts. When the contaminants exceed the capacity of the additive package they'll fall out and form sludge in the pan. It's like trying to pour 6 gallons into a 5 gallon pale. It doesn't fit.The micron size of the filter paper varies from brand to brand. The use of an oil with an SN classification meets the minimum specs for todays highest classification. There are many oils today that are either a synthetic blend or full synthetic but are blended using conventional base stocks instead of a synthetic PAO base stock. As long as a private label or inexpensive oil meets current specs you're OK. I fully agree on the use of a good filter.