VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Mystery Coolant Leak From Front of Engine

I have a mystery leak from the front of the 216 engine on my '41. I checked the hoses and felt under the water pump but it doesn't seem to be coming from there. Is there any way coolant can leak from the timing gear cover?

How this all came about: Was having overheating issues. Replaced thermostat - no help. Used Prestone and then Vinegar to clean cooling system - no help. Replaced radiator - a little help but not quite. Tried Blue Diamond to clean the system - stuff came out the same color it went in as, just like the Prestone and the vinegar.

I was doing all this because I guessed the engine had so much rust in the cooling jackets it couldn't transfer the heat. Case in point: Even when I completely removed the engine block drain, all I got was a drip... drip... drip.

Finally found this stuff called Thermocure. Had it in for a week, running the engine once a day to circulate. The stuff started turning dark red after the first day and after a week, when I drained it, it was absolutely black.

I now get a good steady stream from the engine block drain, so that stuff really works. Or does it work too good?

I'm wondering if there is a gasket or something in the timing gear cover or somewhere else that was being plugged by rust and gunk and this stuff finally cleaned it out. It's not a major leak, but it needs fixing if I can identify where it's coming from.

Did you check the water pump? That could also be the source of the overheating problem if it is sucking in air.

Hello BJSoder,

I had a similar issue with a leak at the front of my 216 and discovered the gasket between the water pump and the block had deteriorated and was leaking ever so slightly so it took a while to find it.

If you have access to a coolant system pressure pump, fill the system to its normal level and add a few pounds of pressure. Don't go over board, just a few pounds and the leak should become pretty obvious.

There is a frost plug in the front of the block, I believe below the water pump. It can rust to the state that it will start to leak. I have had this happen.

The treatments probably desroyed the old water pump seal. There is a weep hole in the bottom of the water pump casting that allows the coolant to drain out if seal is bad.

I replaced the water pump seal about a year ago, but that did occur to me that it's possible I'll have to replace it again. Maybe the rust treatment unplugged the weep hole.

In an attempt to identify exactly where the leak is occurring, I've placed shop towels under the water pump and under the front of the engine. We'll see which one comes out with wet spots. If I don't get a drip or two, may have to run the engine again to encourage it.

And it better not be a cracked engine block. I remember when I cleaned the old gas tank of rust - it exposed over a dozen holes, two that were big enough to push a pencil through.

" I replaced the water pump seal last year"......Are you refering to the seal inside the water pump or the mounting gasket?
Replacing the seal is a major operation. Easier to install a new water pump and get all new internal parts such as the seal, bearing, impeller, etc.

It was the mounting gasket I replaced.

I've confirmed the leak is definitely coming from under the water pump. It didn't want to drip on my shop towels so I started it up and watched with a flashlight. The leak appears to be coming from around the front of the water pump rather than around the gasket. If it's the weep hole, is that a sign of a bad seal? Or how do I tell?

I'm going to have to take it off anyway. Also have a bad thermostat that doesn't want to close fully.

I agree with Gene, in that you need a new water pump.

When you get the old one off you may find that there is play in the shaft. The seep hole helps keep the water from getting on the fan blades and centrifical force slinging it everywhere.

A professionally rebuilt WP with the proper number may be a suitable option from new.

Good luck with it.

With pressure baçk flush the radiator and block. Separateluy would be best.

Best,

Charlie

Took the pump off, filled it with water, and let it sit. The leak is coming from the backing plate gasket. Of course, getting the backing plate off will be a chore - those screws don't want to turn at all, even with a really big screwdriver.

But, even if I can get the backing plate off and the gasket replaced, it will probably leak from somewhere else the next day. Thinking like you say, I should just replace the darn thing.

Update: Went ahead and ordered a new water pump from ChevsOfThe40s, plus new thermostat, all gaskets needed, and a couple of inner rocker panels (gearing up for body work this fall and winter).

When I took the pump for my '37 apart I was able to get the backing plate screws out with an impact driver and a big straight screwdriver bit.

Ah, I'm just going to send it in to ChevsOfThe40s for the $20 core charge and let them (or whoever they ship it to) to rebuild it. At least this way I know I'm getting a rebuilt one which should be good and not have to worry about possibly stripping the heads of the screws trying to get them off, or of the seal deciding to leak after I've replaced the gasket. That would cause me great annoyance and displeasure, to quote the Duke.

Did the same with all four shocks. Sent them in on a swap to Apple Hydraulics. Received four rebuilt ones that so far are working great.

In the future, you may be able to get stubborn plate bolts out by using both suitable chisel and a ball-peen hammer. (A somewhat dull chisel will work as long as it catches the groove/slot.)

Just position the chisel at the outer edge of counter-clockwise position of the bolts head slot/groove. Then use the hammer to tap the chisel. Works for me.

Best,

Charlie