C3 - 1971 - Leak from bellhousing

[Greg F.]

All,

I'm trying to locate the source of a small leak that drips from the bottom/center of the bellhousing.

I have a 71 350/270 hp (all stock). It's a four speed w/AC. A mechanic I've used had the car this week. We changed the valve cover gaskets as they were leaking a while back. He cleaned the bell housing, starter, the shields, the back of the motor, as the valve covers leak a lot previously. No leaks around them anymore. He ran the car on the lift for 25 minutes with the inspection cover off. Everything remained dry. The next day, he drove it 3 miles, put back on the lift and ran it some more. Still remained dry. The car had the rear main seal replaced last year and that was our original thought, but the back of the motor is dry.

I drove the car home today, parked it in the garage and noticed the same leak (about the size of a dime) on the floor. I see another drip on the bell housing - ready to drop. I'm thinking its stemming from the transmission. Isn't there a "slinger" in the trans that makes the M-20's prone to a small amount of leaking? I'm ok with a small leak if it is somewhat normal. Any other thoughts?

Thanks,
Greg

[Steven G.]

Re: C3 - 1971 - Leak from bellhousing

Gregg, I have a 72' with same type leak, I removed engine for restoration and discovered a leak from rear cam (freeze type) plug, behind the flywheel. Steve

[Terry M.]

Re: C3 - 1971 - Leak from bellhousing

My 1970 has had a small leak just like that since new. In the Air Force we called that "normal seepage."

[Joe L.]

Re: C3 - 1971 - Leak from bellhousing

All,

I'm trying to locate the source of a small leak that drips from the bottom/center of the bellhousing.

I have a 71 350/270 hp (all stock). It's a four speed w/AC. A mechanic I've used had the car this week. We changed the valve cover gaskets as they were leaking a while back. He cleaned the bell housing, starter, the shields, the back of the motor, as the valve covers leak a lot previously. No leaks around them anymore. He ran the car on the lift for 25 minutes with the inspection cover off. Everything remained dry. The next day, he drove it 3 miles, put back on the lift and ran it some more. Still remained dry. The car had the rear main seal replaced last year and that was our original thought, but the back of the motor is dry.

I drove the car home today, parked it in the garage and noticed the same leak (about the size of a dime) on the floor. I see another drip on the bell housing - ready to drop. I'm thinking its stemming from the transmission. Isn't there a "slinger" in the trans that makes the M-20's prone to a small amount of leaking? I'm ok with a small leak if it is somewhat normal. Any other thoughts?

Thanks,
Greg

Greg-----


There are many possible root causes for this. The most likely are:

1) minor valve cover gasket leaks that "inconspicuously" work their way down and, inevitably, find their "drip point" at the bottom of the bellhousing;

2) a leaking rear main seal.

[Paul Y.]

Re: C3 - 1971 - Leak from bellhousing

One more place might be on the back of the block by the distributor where the oil guage line connects. I have found small leaks to originate there sometimes. By the time they blow and travel it is hard to find their origin.