Cooling system problem
 

I need help! I am nearing completion of a Model A speedster. Engine is 1928. I heard it run when I bought it 25 years ago. I cleaned it up, put in gaskets and such but no major engine work. The water pump was rebuilt using original style packing when the engine was put in the frame over 20 years ago. The radiator is new. I am running a 50-50 mix of water and anti-freeze. I have run the engine several times and taken a few short test drives. The engine starts easily and runs smoothly. I start with the spark at the top of the quadrant and move it down about 4 or 5 clicks after starting. The water pump has been leaking and I have been gradually tightening the packing nut. The leak seemed to be slowing until there was a loss of resistance in the nut. Now the nut turns quite freely in either direction but does not move in or out. The engine overheats quite quickly. If the radiator cap is off coolant will overflow the top. If the cap is on coolant will dump out the overflow tube. There is no sign of coolant in the oil or oil in the coolant. 1) Is it possible that the packing nut is screwed in past the threads or is it broken or stripped. 2) I am planning to install a coolant system filter to protect my new radiator. Any thoughts? 3) Is a thermostat a good idea and will it help the overheating? 4) What should be my first step at this point? Any help would be greatly appreciated. Thanks. Howie

Re: Cooling system problem
 

If it were mine I would:
1. Re-torgue the head nuts. (Back them off a 1/4 and re-torque)
2. Replace the water pump with a new lealess one.
3. Install a thermostat (160) to help warm-up faster in cold weather.
Then see what happens.

Re: Cooling system problem
 

Did you buy the radiator new or did someone tell you it was new. Almost all model a overheating is related to the radiator. Maybe something got in it to clog it up (think mouse). Might do a flow check.

Re: Cooling system problem
 

The Cheapest thing u can do 1st, is run water only with a rust prohibiter I used to use a 50/50 mix and I overheated, just be sure to put your antifreeze back in the winter. I AT ONE TIME HAD A LEAKLESS WATER PUMP, BUT WENT BACK TO THE OLD STYLE WHEN i GOT A LEAK, HAD TO REMOVE THE PUMP TO FIX, WIT HENRYS OLD STYLE PUMP U JUST REPLACE THYE ROPE Sorry I left the caps on. I do not run a thermostat and have never had a problem, got the car in 2004 been running water ever since, & dont over fill the radiator, Best of luck.

Re: Cooling system problem
 

I have a New Walker Radiator and never had a problem. Don't run a fan cause I run a B V8 pump so a fan can't be easly mounted, but it never ran hot. Not in Florida or in St. Thomas and its always hot there with mountains. Better check your Radiator. Iceman

Re: Cooling system problem
 

As far as the packing nut turning and not getting any tighter, it could be because the bushing the packing nut threads on to is loose in the pump housing. If so, you should be able to see both turning as you try to tighten the nut up.

If that's the case, you need to remove the pump and either get a new bushing or, if the bore in the housing is worn, another housing.

Also, just wondering if you've stuck a thermometer in the top of the tank (through the filler) to see just how hot you're getting. Could be that there's just a bit too much water in the radiator and the excess is getting pushed out the overflow. Either way, good luck and let us know how things turn out.

Re: Cooling system problem
 

Just had the same problem of not being able to tighten the packing nut. Found the packing nut AND the bushing were turning. Pulled the water pump and found the pump housing was cracked. Bushing would turn while trying to tighten nut but I could not turn the bushing by hand. Bought a replacement housing, put all the existing parts (which were new) into the housing and everything is working fine. Good luck

Re: Cooling system problem
 

If you install a new rear bushing be sure to buy the one with the seal in it. Also use the correct lead packing rings and be sure to smear a lot of grease around them when installing them. I always had a slow drip on my first water pump rebuild. After I added grease around the lead packing rings, it hasn't leaked a drop since.

Re: Cooling system problem
 

howie123 ..........................
A thermostat will do nothing to keep you from overheating. If anything, it could be the cause. They have been known to stick, shutting off the flow. Even a good one will restrict the flow, somewhat. Yes, I know all the advantages of using then. But, I never use them.
MIKE :)

Re: Cooling system problem
 

Thanks for the suggestions. Yes, the radiator is new from Bratton's Antique Auto Parts so hopefully that is not a problem. Yes, now that I know what I'm looking at I can see the bushing turning with the packing nut. I will pull the pump and check it out when I get the time. I do plan to install a temperature gauge at the same time. I also plan to install the cooling system filter. I will watch for more suggestion. Thanks again. Howie

Re: Cooling system problem
 

Howie,

Sounds like maybe your water pump housing is cracked. Look closely near where the brass bushing goes into the housing.

Bad news is that you may have to remove pump to see crack!

If there is crack, air may be drawn into the coolant.

Air in the coolant is not good for cooling an engine.

Berts has original housings.

www.modelastore.com

Re: Cooling system problem
 

Running the engine with the spark advanced only 4 or 5 clicks down the quadrant is WAY WAY TOO retarded and will cause overheating. I crank my model A with the spark all the way up. when the engine cranks I quickly pull the spark all the way down. I only slightly retard the spark as needed to control buck at low speed in high gear or in a hard pull as in topping a hill. I have practiced this method for 50 years. There is No advantage in running with the spark retarded, it only causes the engine to struggle and over heat and loose power. If it won't run with the spark fully advanced the timing is off. Antifreeze used in hot weather only contributes to ever heating. I have never found that antifreeze helps control rust in the cooling system. Antifreeze will also leak in places that straight water doesn't leak.

As for the water pump, my bet is that you have ruined it by over tightening the pack nut. It is allways best to back off the packing nut, grease it and then tighten only enough to stop the drip. If you plan to use packing use the teflon rope type. Lead packing wears the hell out of the water pump shaft, I quit using lead packing years ago. I build my own leakless water pumps that need NO packing. I don't and have never used a thermostat in any of my model A's . A thermostat may help as a restrictor on an engine that the radiator can't handle the flow of the water pump. Model A water pumps have a tendency of pumping so much that water is forced out the overflow pipe. When I build my water pumps I grind some material off the tips off of the impeller to slow the flow and keep the water in the radiator. It also helps if trying to remove the water pump without having to remove the radiator. I think that improper spark lever setting is the main reason for your over heating. Good luck.

Re: Cooling system problem
 

Thanks to everyone for the expertise and suggestions. I removed the water pump this morning. I had to pull the radiator to get it out. I took the radiator outside and filled it with water from the garden hose. Water just trickeled out the bottom. I turned it over and backflushed from the bottom. Lo and behold, a pile of acorns. Must have been in the block and I didn't flush it before installing the radiator. I won"t make that mistake again. I continued back flushing until the water ran clear. Filled from the top again and water gushed out the bottom. Should that be sufficient or should I have it flushed by a radiator shop. I also ran water through the engine block from top to bottom. This expelled a few acorns. What is the best way to do a thorough flush with the engine in the car. I will disassemble the water pump and see what I find. Thanks again. Howie.

Re: Cooling system problem
 

I do not think it is necessary to take the radiator to a shop to have it professional cleaned. I would run the garden hose in both directions thru the block several times. I would then put a strainer in the upper hose and check it frequently until you do not catch any more junk in it. It should be just fine.

Let us know how everything works out.

Chris

Re: Cooling system problem
 

Just wanted to post an update. I got a new water pump with leakless rear seal. Installed that. Flushed the block and radiator again. Put the radiator back in with the Gano coolant filter in the top hose. No more leaking from the pump. No more overflowing coolant. The temp gauge ranges between 160 and 190 degrees and climbs higher right after shutting down. Does that sound reasonable. The books call for 3 gallons of coolant but I only got about 2 1/2 in before it overflowed. Does that also sound reasonable. I really like the coolant filter. It is clear plastic so I can see that there is coolant into the upper hose. Thanks for all the advice. Howie

Re: Cooling system problem
 

howie123 ................
Sorry that I didn't get to you sooner, but the next time that you have your radiator off, work over the engine openings with a pressure washer. You will get more than acorns out !
MIKE :)

Re: Cooling system problem
 

Heating up after shutdown is not unusual. The water is not circulating and is just absorbing heat.