holy smokes my radiator boils over

[thomas]

Can't figure out why the radiator is boiling over. 29 AA...all original. Thought a mouse nest gummed it up so I replaced the core and 552.00 later it boiled again and ran hot. I'm a wondering what to look for? Any suggestions?

Tom Moore

[Stakebed]

first off: i have no model A engien experience. so the following will be a general kind of thing

is the belt tight that spins the water pump? is the fan spinning the same rpm as the pump shaft?

maybe the mouse builta nest elsewhere in the cooling system. did you flush it out before you installed the new radiator?

[Neil Wilson]

Unlike modern day vehicles, it is not a good idea to tighten the fan belt very tight. I tighten my belt only enough to get the generator to spin. If you tighten the belt like modern day vehicles, the water pump will soon be worn out and leak!

[mikeg]

Can't figure out why the radiator is boiling over. 29 AA...all original. Thought a mouse nest gummed it up so I replaced the core and 552.00 later it boiled again and ran hot. I'm a wondering what to look for? Any suggestions?

Tom Moore

Don't forget to look at 'non-cooling system' possibilities, such as poor timing, fuel mixture ect.

Other issues may be a colapsed or blocked hose, possible failed (or missing) tstat in the waterpump rad hose neck.

[E.Moore]

You may have more mouse nest materials inside the engine, which may now be back in the new radiator. Once mice get into the radiator, they can easily get down into the engine and fill the block with nesting.

If it were mine, I'd remove the radiator and have it flow tested at a radiator shop and cleaned or rodded if needed, flush the block thoroughly with the water pump removed.

Running a 1000 - 1500 psi pressure washer in the block generally removes most debris inside the cooling system. Check the lower return pipe and the water pump impeller.

Once everthing is back on the engine, fill the radiator with water or coolant and run the engine. Look for air bubbles, which could be from a leaking head gasket or crack in the block or head.

Ignition timing that is too retarded will quickly cause the engine to overheat. If the exhaust manifold turns red, the ignition and or carburetion needs to be adjusted.

A clean cooling system and properly working carburetor and ignition system will allow the Model A-AA engine to run cool.

[Roadster AA]

I had trouble with my A engine overheating.I took the head off, checked for cracks, put a new head gasket on and. Still overheat. I checked the timing, rebuilt dist, Still overheat. I rebuilt the carb. Still overheat. I took the rad. to a shop and had that flushed and redone, Still overheat!!
Ok, had to be a crack in the block somewhere, Pulled motor. Started to take it apart and I found that the Timing Gear was off by ONE TOOTH!!
Put new timing gear with tooth in right place. AOK!!!Went in 4th Prade today.. GOOD LUCK

[AA157'31]

2 months ago, one of my mentor model a guys, with over thirty years of restoration, and 6 present various model a's, was working on a client's car, which was boiling over. after trying many things, from a new head gasket to a full radiator check, found when he was putting the radiator Moto type thermometer back in, that he replaced one of the nuts on the base of the cap, over some thing, instead of under something. switched the position of the nut..wallah. good luck.

[ogersbronco]

My brother AA keeps overheating. We have gone through three different radiator, two different blocks, we have checked the timing and fuel mixture. It will idle fine for long periods of time but once your on the road for a couple miles it will start to boil over. Are speed was around 20-25ish. Any thoughts or suggestions?

[James A Lake]

When I bought my A pick-up home it also had a mouse nest in the radiator. I had the radiator cleaned and reinstalled it.. First trip out it over heated again..The mouse had gone deep into the engine, I had the radiator cleaned again, pulled the head and used high pressure air and a shop vac with the holes on the block taped close and kept cleaning and flushing.. For the 3rd time I reassembled, Went for a ride and it just ran hot, did not boil over..With the help of a club member, We did a cooling clinic at our monthly meeting.. During the discussion, another member had found a shop that unsoldered the tanks and carefully rods out the tubes..I pulled the radiator for the 4th time and had that done..When I picked up the radiator, the guy told me 90 tubes were plugged and he resoldered the baffle plate and over flow.. I reinstalled the radiator and it has worked excellent..I AM NOT AN AUTHORTY, I would like to share lessons learned.. Know that the Radiator is 100 percent clean, baffle is in right place, overflow tube is not plugged,waterpump is working, engine is timed correctly..

[KingGeorge]

When I bought my AA it had overheating problems. It turned out to be a head gasket leak.

[ogersbronco]

I need your help. I have a 29 Stake body and it will steam badly after I drive it. It used to boil over but not it just steams. If I let the truck fast idle for about 10 mins it will start to steam and water will run out of the overflow tube, but it will idle all day long with no problem. If I take it for a drive I can get around the block and then it just steams really badly. After I drove it around the block I let it cool all the way down and when I refilled it, I used two gallons of water to refill it. This doesn’t seem like it is right. I am on my third different radiator and second block. I change the head gasket, checked the timing check, the fuel mixture, water pump seem to me moving the water fine. The fan looks good and I can feel a good amount of airflow throw the radiator. Any suggestion? I am trying to get it ready for the New England Meet. Please I need help.
Thanks,
Mike

[E.Moore]

If your muffler is partially stopped up, it will cause the engine to overheat. If all of the exhaust isn't getting out, the cylinders will become much hotter than normal. Engines that have this condition will normally idle fine, but when the rpm and load is increased, the engine overheats. If all of the preliminary checks have passed on the ignition, timing gears, carburetion and cooling system, the last item is the exhaust system. Hope this helps.

[ogersbronco]

I took my brother 30-31 radiator and tried it on my 28-29 and it work fine. No steam or overheating problems. I did a flow test between the two radiator and the 30 passed the test with flying colors. The 28 took about 8 sec to empty. Now I need to find a 28-29 radiator. I have been looking around and haven't a place where I can get one. Does anyone know where I can get one? I did notice that some places sell a 28-29 A heavy duty radiator. So what is the difference from a 28-29 A heavy duty radiator and a 28-29 AA radiator?