The Stovebolt Site Forums The Shop Area Engine Shop coolant leak from clutch underpan

I have a 53 3100 with a 216 and 3 speed that is just a yard driver that I start and move occasionally. I started it today and found that it would grind when I tried to put it in gear. I shut it off and discovered coolant leaking from the drain hole in the clutch inspection under pan. I'm thinking that the clutch disc might be rusted to the flywheel. Does anyone out there know if there is a freeze plug on the back of the head or motor? Hope I don't have a cracked block. I have kept antifreeze in the radiator, but did flush out the cooling system a year ago when I bought the truck. It had sat for years. George

Yes, there is a big freeze plug back there. It requires removing the flywheel, and possibly the bellhousing to change it. Flushing the system with an aggressive cleaner will sometimes open up holes that were being plugged up by rust and crud on low or "no-pressure" cooling systems. You might try warming the engine up well and dumping a can of Bar's Leaks into the radiator if you don't want to go to the trouble of pulling the transmission, clutch, flywheel, and bellhousing. It will either fix the leak or it won't, and it might save you a bunch of labor on a vehicle that doesn't get worked hard and driven frequently.
Jerry

I figured there must be a freeze plug back there. I did do an aggressive flushing of the cooling system and probably opened up a hole. The old 216 smokes and knocks and a previous owner at one time brazed shut the breather vents at the top of the valve cover. I could probably try stop leak but the clutch is still stuck and I can't drive it anymore and resale value just dropped. I figure if I'm going to pull that motor, it will be to drop in a 235. Time to cover it with a tarp and forget about it for awhile.

There's a quick trick for getting the clutch to break loose. Start the engine with the transmission in gear, accelerate a little, fully depress the clutch pedal, and nail the brakes. The disc will either come loose from the flywheel, or the engine will stall. It might take a few tries, but I've done that little trick successfully several times.
Jerry

Good advice but the truck doesn't have brakes. After some pondering, with the motor off, I put it in gear and bumped the starter repeatedly about 10 times and it broke loose. I then ran some stop leak through it and the leak stopped. Now I have bought some time to look for a 235.

If you only use it infrequently, make sure to get fuel without alcohol, otherwise, you are likely to get a stuck valve resulting in a bent pushrod or worse. Airports, tractor suppliers, have such fuel.

Ed

Here's a photo or two of a 216 with a potentially leaking rear core plug. Just pulled the bellhousing off to clean things up, and found rust and crud that matches up with the core plug on the back of the engine. I have a feeling that the cam plug is leaking (oil) as well, as it was really grimy there, with the rear main area being relatively clean. The plan is to replace both plugs.

Pulled the rear core plug today.

Do you think I should flush out the block?

I think you should go one step further and have it boiled out.

Well, that's not going to happen Phil, But I may fill it with some cleaning solution and let it sit for a while. That gunk you see behind that core plug is pretty soft and should wash out pretty easily. I don't plan on tearing the engine down enough to get it hot tanked. It runs as is, (well, it ran before I pulled it out) but has some serious oil leakage that I need to deal with. Timing cover seal and gasket being one. The rear main seal doesn't seem to be leaking much, but that core plug at the rear of the cam is suspect.

What does the drain on the side of the block look like

The drain is clear. I flushed it out with a pressure washer today and get good flow out of the drain. But there's still a fair amount of sludge below the two core plugs on the driver's side, which I removed as well. Once I get it on the engine stand, I'll wash that out.