Bill wrote:

> The sudden overflowing and bubbling sounds like a head gasket leak, which
> usually occurs between the cylinder and a water channel, allowing the
> compressed gasses in the cylinder to presurize and leak into the cooling
> system.  If this is it, get it fixed quick as several serious problems can
> result.  One problem is that it can blow all your coolant onto the road,
> which means the temp sensor doesn't work because there is no coolant around
> it, and you don't know you have a problem until the engine seizes.
>
> It also sounds like your fan thermostat is going south.
>
> Good luck.  I hate cooling problems.

Thanks Bill,

I think I'll see if a radiator shop can detect exhaust gasses in my coolant.
I suspect I have blockage in the radiator as well and this is causing the fan
to not come on.  Low coolant flow means the fan thermostat  in the radiator
would never heat up enough to trip (unless I'm idling and there's no wind
through the radiator).

Thanks again,

Dick