model A overheats

W

wagonshed

New member
Looking for suggestions on what to do next on my "29 model A speedster. When the air temp is approaching 80 degrees the red of the temp gauge is in the gauge's circle. Temp of high 80-90's she'll boil over. Engine was rebuilt perhaps 10 years ago, newer leak proof water pump, checked timing and carb adjustment and cleaned radiator with permatex radiator cleaner twice. Don't know age of radiator, any suggestions other than replacement? Thanks
 
I put vinegar in all my rads and wait 6 weeks. seems to work every time. Some guys prefer Evaporust, which works much more quickly, but 90. for a 5 gallon drum.


In any case, it shouldnt be your motor, if it was in fact rebuilt properly.
My roadster was quite stubborn. despite flushing it with vinegar, I had to go back and do it again and the "mud" that came out of it, was amazing. now running as cool as a cucumber!
 
New radiator needed. Money well spent and another item off the list of “need to do”.

Enjoy.
 
Make sure you're running the spark lever properly. Pull it down until you hear it ping when pulling hard, then up a click or so, just enough to stop the ping. Most model a radiators are crudded up, if you can't get it clean replace it. You dont want to ruin your new engine.
 
You could time a draindown of the radiator which would indicate how well it flows. I can’t remember what the preferred time result is, but I’m sure someone here can give a better description of the process and desired time.

Or you might find that test procedure here: http://www.fordgarage.com/
 
wagonshed, it is almost always the radiator. I must say, I had the same symptoms with the radiator on my car after I bought it years ago. It had a Sears 2-row radiator in it.
 
wagonshed said:
Looking for suggestions on what to do next on my "29 model A speedster. When the air temp is approaching 80 degrees the red of the temp gauge is in the gauge's circle. Temp of high 80-90's she'll boil over. Engine was rebuilt perhaps 10 years ago, newer leak proof water pump, checked timing and carb adjustment and cleaned radiator with permatex radiator cleaner twice. Don't know age of radiator, any suggestions other than replacement? Thanks
Click to expand...

Check the accuracy of your temperature gauge, coolant level below the baffle, advance the timing with the hand lever, water with antirust added will run cooler by 20-25 degrees!!!

Guys he wants answers other than replacing the radiator.
 
First lets determine what the temperature of the coolant actually is.
Pick up an inexpensive dial meat thermometer and stick it directly into the coolant through the radiator neck.
Knowing the actual temperature rather than it's in the red is important.

By the number of posts that you have I am assuming (perhaps incorrectly) that you are new to the Model A engines.

Many new to the hobby tend to fill their radiators very close to the top and as the coolant warms up it expands and will push out through the overflow tube. This looks a lot like it is overheating when it is actually not.

You do not need to or want to "fill" your radiator. Just keep an eye on the coolant level and resist the urge to put more in as long as the top of the tubes in the radiator remain covered with coolant. The engine will push out excess coolant until it finds the level it is comfortable with.

As far as coolant it is hard to beat a 50/50 mixture of coolant and distilled water.

It is possible that you have a head gasket that is leaking. At temp and under load blow by can push water out too.

Have you checked the torque on the head nuts?
 
Yes, if you get bubbles in your radiator you have a head gasket that is seeping combustion gasses into the water jacket. And that surely will heat things up.
 
If you have a lot of tubes in your radiator really plugged, vinegar or other solutions will likely not clear……the only sure way to unclog them is to have it rodded, by someone who knows how to do it. My radiator had over 20 tubes totally plugged, had it rodded, and all but a few were cleared…..no more overheating!
 
Thanks for all the great replies, I now have a number of new things to verify, sometimes half the problem is just knowing what to do.
 
Big hammer said:
Check the accuracy of your temperature gauge, coolant level below the baffle, advance the timing with the hand lever, water with antirust added will run cooler by 20-25 degrees!!!

Guys he wants answers other than replacing the radiator.
Click to expand...

LOL so true, but the radiator might be the only fix. Try cleaning it first. I cleaned my original 1928 radiator by running with vinegar for a month. It made quite a mess, but did clean it.
 
Good afternoon Tom...How much Vinegar did you use in the system? Mixed with water or was it all vinegar? Thanks, Ernie in Arizona
 
Ernie,
I use 2 gallons of vinegar, which as I recall was about 5% acid. The vinegar took the off the grease on the lead packing seals and made the original water pump leak and make a mess all over my engine. I cleaned it with diesel and WD-40. If my water pump would have had the double lip seal, it probably wouldn't have made the big mess, so now I use the seal for added protection on my water pumps.

I bet doing a search for "Tom Wesenberg engine mess" will turn up pictures of it.
 
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