Re: Overflowing with Antifreeze

[Mike Substelny <msubstel@xxxx>]

Mike Allred wrote:

> Today while driving my D. it was about 92 degrees and my temperature gauge
> never showed hot but when I stopped and cut off the engine it was over
> flowing antifreeze through the overflow hose. The radiator fan never cut on.
>
> Where do you think my problem is? Temperature gauge, fan, temperature
> sending unit or other?

Because your temp gage never got high I will assume this is not an electrical
problem. This is a plumbing problem.

Several things could cause these symptoms, but if you are lucky it is just air
in your cooling system and/or low coolant. Top off your coolant, then bleed
your system or install a self-bleeder.

The second most lucky thing it could be is a bad radiator cap. Considering the
age of our car, I expect bad radiator caps to start coming up more often in the
coming years.

Liquid cooled engines use pressure to keep coolant in liquid form even when they
are heated above their boiling point. They operate in a very specific
pressure/temperature range. The systems use spring-loaded radiator caps
designed to release coolant if the pressure gets too high. Coolant is released
through that overflow hose. Because it is hotter than its boiling point,
coolant released by a radiator cap boils the instant it hit the atmosphere.

Over time a radiator cap spring and seal will wear out. When they do, the cap
can release steaming coolant from an engine that is operating normally. Tjis
might be exactly what happened to you.

You can test your radiator cap with the same pressure tester you use to bleed
your cooling system. If you do not have a pressure tester, just inspect the cap
visually. You might get lucky and find the cap is worn out and there is nothing
else wrong with your DeLorean.

Either way, DO NOT drive a DeLorean with an overheated engine!

- Mike Substelny