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Was this vapor lock? On the way home from G.N.

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Caddy Daddy 55:
Living in Wisconsin I have never experienced vapor lock. I will try to explain what happened. On the way down to Louisville we had no problems but the temperature was cooler. We drove the 55 Cadillac for about 2 1/2 hours then filled up with premium  ethanol fuel. Then drove 20 minutes to a restaurant for breakfast spent about 45 minutes in the restaurant. The temperature outside was about mid 80’s. Went to start the car fired once then just kept turning over. Opened the hood and saw no gas in the glass fuel filter bowl. Removed the filter and had the wife turn over the engine no fuel. Removed the top nut on the fuel pump cranked engine same result. I replace the rubber fuel line that went from the steel feed line to the pump before going to G.N. So I wouldn’t get points taken off. I had the original line that I have used for years with me so I changed it out the I.D. of the original line fittings are bigger then my new line. The line I took off was warm and I had it routed close to the engine. While I was doing this Diane went and got some starting spray from a gas station. She also went in the restaurant and got a bag of ice that I put on the fuel pump. I sprayed some starting fluid down the carb while she cranked the engine it fired off the ether then quit cranked again and gas appeared in the filter bowl. Car ran great all the way home. Sooo was this the dreaded VAPOR LOCK! Or was it something else?

Thanks for reading any help would be appreciated.

Bob Kielar


Either that or the fuel pump having issue with pumping fuel into the carb. Since you took care of two possible problems (heat related) the fuel line (replacement) and cooling the fuel pump (ice bag).

I recall reading somewhere the way the fuel pump in located heat can cause the diaphragm to degrade pumping as it expands and with no fuel going through the pump to cool it a bit it is a vicious cycle.   :(

I believe others have experience the same problem after the engine if shut-off after a drive but not so much while driving it.

G Pennington:
Classic vapor lock.  You drove the car for 2 1/2 hours, got things nice and warm, then parked it.  The fuel pump became "heat soaked", allowing the fuel in the pump to vaporize (no fuel flow or air movement).  The pump is designed to move liquid, not vapor.  Once cooled down, the vapor condenses and everything ok.
The usual fix is to install an in-line electric fuel pump back by the gas tank.  Get one that will allow the mechanical pump to pull fuel through it when not energized.  You would then only use the electric pump when needed to overcome a vapor lock condition.  Also, the use of non-ethonol gas (higher boiling point) or additives may help.  Much has been written about this subject on the CLC general technical forum.
Gary Pennington
1953 Convertible.

I agree with Gary. Vapor locked it.

Sounds like vapor lock to me. I hate vapor lock, it is not a good experience. Phil


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