Conditions for overheating

Michael M

Michael M

Senior Member
I suspect I know the cause, but am looking for affirmation or something else to explore.

It happened after sitting for a few hours at the car show (85 degrees and sunny). Going a fairly steady 40 mph, drove 5 or 6 miles when the 31 Tudor began to overheat, steaming and coolant pouring from the overflow. Pulled over and measured the coolant with a thermometer - just a tad over 190 degrees.

After letting her cool for awhile, I added about 2 quarts of coolant and made it home without further trouble.

Now what I suspect: first, the spark was fully advanced (I usually run the lever about 3/4 down). Secondly, the GAV was about 1/2 turn open (I usually run it almost fully closed when the engine is warm. I think I left it this way after showing someone how it works and just didn't notice while driving.)

Other items to consider: I use the nail in the overflow. Ran the vinegar treatment about month ago. The coolant in there now is bright green with no visible rust or discoloration. Never overheated before, and hasn't since when I drove the car as normal.

So my question: could the fully advanced spark and/or open GAV have caused the overheating.

Your thoughts and opinions are welcomed.
 
First, what is the past history? Has it overheated before? If the timing is set correctly, you do not need or even should normally use full advance all the time, but I would not think that would cause your overheating. And having the GAV open more than normal...richer rather lean, also would not cause it. You mentioned cleaning with vinegar; if you have some clogged tubes, which I would suspect, then you need to have your radiator rodded by someone who knows how to do it. Vinegar and other treatments will not unclog badly clogged tubes
 
The car has never overheated before. Timing is dead on. I did the vinegar cleanse mainly as a precaution to clean out the system. When the head was off last year rust was not seen in the visible parts of the water jacket and when the radiator was drained at least the top of the visible tubes seemed clear.
 
Maybe your vinegar cleaning loosened things and clogged the radiator.. Just a scenario..
Have seen good rads get clogged that way.
A radiator will act like a big filter

You know the old saying if it's not----- don't ----- with it
 
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I was thinking the same as Mitch.
Since this has happened, I'd remove the radiator, lay it flat (face down), fill it with water, then dump it into a tub by holding it upside down, and see what comes out. Do this a few times. If you get some rust flakes, you should add a filter to the top hose. I got another one of those Catapillar brass filters that fits in the top hose. Now I need to find it so I can post the number on the box.
 
Running with the timing retarded (lever up) is what will cause overheating, not full advance; likewise, having the GAV open richens the fuel mixture which has a cooling effect. Too lean is what will cause overheating. So as mentioned check for clogged tubes in the radiator.
 
40 Deluxe said:
Running with the timing retarded (lever up) is what will cause overheating, not full advance; likewise, having the GAV open richens the fuel mixture which has a cooling effect. Too lean is what will cause overheating. So as mentioned check for clogged tubes in the radiator.
Click to expand...

Yes, while your static timing is dead on, your driving timing is way off.
 
You probably do have plugged tubes, but I hope you have re-torqued the head a few times since you had it off. That would do it.
 
Thank you guys. I guess I reversed the advanced / rich and retarded / lean effects.

Guess I got some work to do.
 
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