Rodger in Seattle has given me lots of new leads for finding the source
of my overheating engine. I'm going to wait to check out a few other
Amphies in Mt. Dorao before I take more action. Personally, I'm hoping
the problem is the top seal. It's a lot more easy to fix than pulling
the radiator and oil cooler out AGAIN. I already bought the garage
door seal as suggested by John Bevens and Tommy in Tampa. I'm going to
install it eventually, but before I do, I want a few others to see the
condition of my originals. Thanks again for all of the advice. I'll
post my results in a couple of weeks.
Arnold
Johns Island, SC
>You say: "When the temperature needle finally edges up to the hot zone, I
>slow down to 45-50 and she begins to slowly cool. If I stop and idle, she cools
>faster."
>
>This evidence indicates you likely do have a cooling problem, not just a
>miscalibrated temperature gage. BUT, since it is easy to do, I recommend that
you
>first check the actual water temperature. If you don't have a thermometer
>that will work, you can get a cooking thermometer cheaply (probably $5 or
less).
> To check the temperature, simply remove the radiator cap (when the engine is
>cold), and stick the thermometer in the hole. Drive the car until it gets
>over temperature (on the dash gage) and then go back and check the thermometer
>in the radiator. I think the Amphi thermostat is a 160 degree thermostat
>(quite cool by today's standards). If the temperature is more than 10 degrees
over
>set temperature of the thermostat, then you definitely have a cooling problem.
>
>Now, I'm quite skeptical that the rubber seals around the radiator are your
>problem under the conditions you describe. At 70 degrees and highway speeds, I
>doubt that even missing seals would cause a problem. The seals would be more
>important at lower speeds with high power requirements form the engine (like
>climbing a steep hill in 2nd gear, or running "flat-out" in the water).
>However, testing if the seals are a problem would not be hard to do either.
Simply
>hang a normal thermometer above/behind the radiator. You can hang it from one
>of the louvers on the engine cover. Again drive the car until it gets hot.
>Then stop and very quickly read the thermometer (before the temperature can
>change much). I if the temperature reads under 90 degrees, then I would be
>confidant that your rubber seals are not the problem (in 70 degree air I
suspect
>you will find the temp here is more like 75 to 80 deg.)
>
>OK, so here are my thoughts on other possible cooling problems:
>
>Clogged radiator -- I agree with your assessment. Even with the flow test, I
>think a clogged radiator is the most likely problem. Since Amphicars don't
>have the excess cooling capacity that modern cars have, even if your radiator
>is only 1/3 clogged it might cause the problems you are seeing. Also, as you
>noticed with the oil cooler, the fins can be clogged preventing air flow. I
>assume the radiator shop cleaned these out before painting it, but you should
>check just to make sure. If the fins and tubes are otherwise in good
condition,
>then you can have the tubes "rodded out" -- removal of the end tanks and
>cleaning of the tubes. However, it might be just as cheep to have the radiator
>re-cored as was already suggested. Re-coring means replacing all the tubes and
>fins with new ones (the end tanks are reused). This assures optimum cooling
>performance.
>
>Loose fan belt -- While I don't think this is real likely, it's very easy to
>check. If the belt is loose, it may be slipping and thus not spinning the fan
>and water pump fast enough. While your checking the belt, take it off for a
>minute and check that the water pump and generator both spin freely.
>
>Bad head gasket -- If the head gasket is bad, it can let exhaust leak into
>the cooling system causing overheating. The best way to check for this is to
go
>to a shop with an exhaust gas analyzing machine. They can stick the probe in
>your radiator and "sniff" for exhaust fumes.
>
>Stuck thermostat -- It fits with your description, but since you had the same
>problem with no thermostat, this is obviously not the solution.
>
>Bent fan (or missing fan blades) -- While this could cause cooling problems
>(especially on an Amphicar that relies heavily on the fan to move air), I doubt
>this is your problem. If it was, then your car probably wouldn't cool faster
>at idle.
>
>Damaged water pump -- The water pump could be missing blades, or the blades
>could be loose and spinning on the shaft. But again, you probably wouldn't get
>better cooling at idle if this were the cause.
>
>Big exhaust leak (maybe) -- If your exhaust is going into the engine
>compartment instead of out the back of the car, it might add enough heat to the
engine
>compartment to make your engine overheat. But, if this were your problem,
>you should HEAR it LOUD and clear.
>
>That's all I can think of. Check your fan belt, and verify that the engine
>is actually getting too hot. If it is, then have the radiator rodded-out or
>re-cored. I'd bet money that this will fix your problem.
>
>Roger
>White '63
>Seattle
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