The Stovebolt Site Forums The Shop Area Engine Shop 216 Water Pump, T-Stat, and Other Cooling system Questions

Otto, that looks like a Dr. Damper unit. The rubber can fail on those. Mine did, right away. They fixed it for free. Been fine since.

The stock Chevrolet ones look different. The damper itself is larger with the smaller pulley in behind closer to the engine.

Tommy, hold on. The damper in my picture is from a '66 Mustang. I just posted it for reference because it's the only style I'm familiar with.

52Carl describes the Chevy unit as being a sandwich stacked perpendicular to the crankshaft axis and impossible to slip and separate like the one I posted. I just wanted to make sure that I understood him correctly.

In any event, I removed the belt and the balancer is intact and not coming apart. I actually was hoping that I'd find the sheave spinning on the hub - easy fix, but no luck there.

My balancer is probably original to the engine. Crank snout also has the hand crank provision.

Otto, any update on your issue? Would like to see you and Old Roy at Minters farm next month.

Over the weekend I tried unsuccessfully to flush with muriatic acid. The engine overheated rapidly and boiled over like Old Faithful.

I'm now pretty certain that there is a blockage in the water jacket preventing adequate coolant flow..

A couple times when I opened the petcock on the block, water dribbled out until I jabbed an ice pick in the hole and then it flowed out steadily. The weird thing is that there is no glop or sediment in the water.

I'm probably going to have to pull the manifolds in order to reach the casting plugs and remove them.

I will probably get a block test kit prior to tearing everything down just to confirm that the problem is not exhaust gas in the coolant. No bubbles are observed, however until the water starts boiling.

The other problem that's developed is that a crack that a previous owner repaired is now weeping. That will have to be addressed as well, once the blockage problem is solved.

I suspect whatever was used to patch the crack lost its bond due to the excessive heat. It's right down there by the petcock where these engines all seem to have cracks.

Your water pump was fine then?

Just had it rebuilt.

Right, but that was not your coolant problem?

Obviously not. I figured as long as it was off and the whole radiator and everything was out it made sense to send it off for a rebuild. The impeller times look somewhat worn when compared to other pictures of similar water pumps. In any event the only two possibilities that appear to remain our lack of proper coolant flow due to a blockage or exhaust gas entering the coolant. I've already done one test to check for an exhaust leak that seem to indicate that there was none. The evidence is pointing toward a blockage in the water jacket

Just to check for head-gasket problems or cracks if you haven't already done this, see if you can get somebody to stick an exhaust- gas analyzer probe into the radiator fill to check for exhaust gasses which may be there even in the absence of bubbles. It's a bit of a long shot but that's one more thing you could eliminate.

Unless the block is totally filled up with stop leak, you should be getting *some* flow. The bone-yard 261 I bought had a couple of inches of black, hardened stop-leak in the bottom of the block and I had to chip it out with a long screwdriver.

BTW there is a soft plug in the back of the block behind the bell housing that you can't get at even with the bell housing removed. You have to pull the engine.

Block tester is next on the agenda. No evidence of stop leak or anything in the water jacket. Water keeps running clear without crud or particles.