21 stud motor oil leak rear of pan area

[31Abone]

1934 21 stud motor leaking oil out of rear pan small hole under flywheel about a half cup when hot after a run ..do I need to pull the motor to fix it ?? oil getting on clutch and chattering ..

[JSeery]

That's not really part of the oil pan (as in the part that contains oil). It is the lower flywheel/clutch cover. The hole is to allow any oil that gets past the rear main seal a place to escape. And the rear seals tend to leak. The oil is leaking down between the rear of the block and the flywheel and should not get on the clutch surface. One reason for the rear seal to leak (which is basically just a slinger) is over filling the oil or something else that is increasing the oil escape through the slinger. There should be a cotter pin in the hole that jiggles around to keep it open.

[ford38v8]

Too much oil in the crankcase, or parking on an uphill slope will cause oil to run over the slinger into the clutch cover, but the clutch chatter would be caused by loose or worn out motor mounts.

[Adam/Mill Valley CA]

I had the same issue with my '36, which has a poured-bearing 21 stud motor. There is a cork gasket strip separating the main oil pan from that rear clutch/flywheel chamber, it had basically corroded to the point where it was no longer keeping oil in the pan. Pulled the oil pan, replaced the seal and all was well.


Adam

[31Abone]

Good reply's.. I'm familiar with Model A and B oil slingers and the return pipe, does 21 stud have a return pipe as well ? guess I need to drain oil and see how much oil is in pan ,reinstall and add 5 quarts and calibrate dip stick..plugs look good "not perfect" and no exhaust smoke..I started motor on the hoist while running and could see no oil leaks ..but at speed on the road and then stopping oil comes out of clutch cover drain hole at a rapid rate.....fun never ends with old cars.

[JSeery]

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Originally Posted by 31Abone

Good reply's.. I'm familiar with Model A and B oil slingers and the return pipe, does 21 stud have a return pipe as well?

Some do and some don't, almost need to check to be sure.

[Ken/Alabama]

A worn rear main bearing with too much clearance will cause it also.

[mumpsimus]

Originally Posted by Adam/Mill Valley CA

I had the same issue with my '36, which has a poured-bearing 21 stud motor. There is a cork gasket strip separating the main oil pan from that rear clutch/flywheel chamber, it had basically corroded to the point where it was no longer keeping oil in the pan. Pulled the oil pan, replaced the seal and all was well.


Adam

Adam, I’m going to investigate if my motor has the same failed gasket. Where did you buy your replacement gasket?


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[Jack E/NJ]

As I recall on my 21-studder, there seemed to be a leaking deteriorated. broken & misaligned cork/rubber composite pan/slinger gasket. It's shown in red highlight on the VanPelt image below. A replacement wasn't found or included in my gasket set nor did I find a part number. So a replacement was fashioned from an old neoprene spin-on oil filter ring gasket held in place with contact cement. Jack E/NJ

[mumpsimus]

Originally Posted by Jack E/NJ

As I recall on my 21-studder, there seemed to be a leaking deteriorated. broken & misaligned cork/rubber composite pan/slinger gasket. It's shown in red highlight on the VanPelt image below. A replacement wasn't found or included in my gasket set nor did I find a part number. So a replacement was fashioned from an old neoprene spin-on oil filter ring gasket held in place with contact cement. Jack E/NJ

Thanks Jack! That image helped me to understand. I can make up a similar gasket.


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[mumpsimus]

Originally Posted by Ken/Alabama

A worn rear main bearing with too much clearance will cause it also.

I’ll see if I can replace the rear main bearing while I’m down there. And add a drain tube if there isn’t one.


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[Lawrie]

You won't be able to replace the rear main bearing, as its a poured one.
Lawrie

[Mac VP]

Don’t forget while you’re working in this area to replace the oil pump idler cover gasket on the backside of the block. It’s not unusual for the five bolts to be a little loose too. It would leak plenty of oil if the cover was not tightly sealed to the block.

[deuce lover]

Ken/Alabama has it right.Happened to a buddy with a poured main bearing 21 stud engine.He pulled the pan and pieces of the Babbit showed up in the pan.Time to look for a '36 LB insert main bearing block.

[bobH]

Originally Posted by deuce lover

Ken/Alabama has it right.Happened to a buddy with a poured main bearing 21 stud engine.He pulled the pan and pieces of the Babbit showed up in the pan.Time to look for a '36 LB insert main bearing block.

I believe I remember this.... But, my recollection is that there was also a 'benefit'... The substantial leak caused an oil film to cover EVERYTHING under the car (34 sedan), from the pan rearward. It was a great preservative, resulting in nothing got rusty. Of course, the 'downside' was something like a couple quarts of oil every 50/100 miles.

[deuce lover]

That was Apple Valley.Good memory ,Bob.

[mumpsimus]

Originally Posted by Mac VP

Don’t forget while you’re working in this area to replace the oil pump idler cover gasket on the backside of the block. It’s not unusual for the five bolts to be a little loose too. It would leak plenty of oil if the cover was not tightly sealed to the block.

Thanks for the tip! I’ll look into that too.


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[FlatheadTed]

I have had this problem to ,to solve it you can Glue two pieces of 3mm neoprene rubber mix together with contact adhesive .The tube needs to be fitted as well , that worked for me ..