In a message dated 9/7/2005 5:51:25 PM Central Standard Time,
acekraut11@aol.com writes:
> I have an intermittent problem with excess pressure in my cooling
> system. A couple times over the last few weeks the car has puked or
> leaked coolant. One time the car looked like old faithful and was
> shooting steam and coolant out of the radiator overflow bottle. Last
> night the car did the same, although it wasn't nearly as bad, more
> burping it out rather than shooting it out forcefully. A few times the
> heater valve has leaked while opening, at other times it works fine
> with no leaks. After waiting overnight for the engine to cool down this
> morning when I got up I filled the radiator with about a quart of water
> and squeezed the top radiator hose to help "burp" the system a little.
> It seems that I might have some air trapped in the system. Might this
> be the case or am I looking at some other problem? Everything in the
> cooling system has been gone over with the exception of the engine
> itself. The engine appears strong with no leaking of coolant or white
> smoke while it is running. The radiator has been flushed in the past,
> and the car has new hoses and thermostat(last year). The car does not
> overheat. The cap is the "correct" one from TRF for my model year car.
> I cant remember what pressure it is rated at but it does have a 7 on
> top of the cap. I seem to recall that there was also a 4lb cap? Did
> someone mention that they had switched to a 4lb cap and it had solved
> there problem with heater valves leaking?
>
Hmm. It sure sounds like it is overheating. Perhaps it is not showing on
the gauge. And the reason it would not show on the gauge is because the
overheating is localized somewhere in the engine. This could be caused by an
air
bubble or a cooling system clog that is preventing coolant circulation in a
portion of the engine allowing the surfaces to overheat and create the steam
that is
powering your geyser.
Since you have already checked the radiator, cap and thermostat, the first
thing I would look for is air in the system. But TR6's are not prone to air
bubbles (unlike the TR7) and once the thermostat opens all the air in the head
will quickly migrate to the radiator where it can be displaced by more coolant
in the morning.
The next step is a block flush.
BTW, at what altitude are you? Remember, the boiling point of water drops at
higher altitude. When I first put my TR8 on the road in 2000 it ran fine for
a month at sea level (St. Louis is about 500 ft above which is effectively
sea level). But once I hit 7000 ft on my trip to Portland, OR it belched
coolant. All because of a faulty radiator cap. A new cap solved the problem.
I
don't know if Topsham is on the coast or up top one of your mountains so I
don't
know if this is a contributing factor.
Good luck
Dave Massey
57 TR3
71 TR6
80 TR8
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