[TR] TR3 Maradyne Heater

[Dave1massey at cs.com]

In a message dated 11/7/2011 1:35:39 AM Central Standard Time, 
wsb1960tr3a at att.net writes: 
>     A couple of years ago I installed a Maradyne heater in my TR3A. It 
> was 
> designed for a farm tractor, but fit in the TR. I got the idea from HVDA 
> who did 
> the same. It has worked very well compared to the original TR3A heater or 
> a 
> Triumph Spitfire core that I was using before the Maradyne. Anyway, we 
> just had 
> our second snow here in Tehachapi and the heater is blowing cold air. I 
> checked 
> the valve on top of the head and when the car is running, water is going 
> through 
> there. I gently blew the heater core out with a garden hose and it looks 
> clear. 
> What could be downstream from this that would block the coolant from going 
> 
> through the core? The car is running a 185 thermostat and getting up to 
> temperature. I have the radiator part way blocked off to try to keep the 
> heat in 
> the engine compartment. The hose feeding the heater core is warm (not hot) 
> and 
> the hose leaving the core is cold.
>      The last communication I had from FT was that he told me he had a 
> heater in 
> his TR that would burn you out of the cockpit it worked so well. I wonder 
> what 
> he had. I wonder what happened to his TR, does anyone know?
>      Man, I am tired of trying to stay warm in a TR. Driving it to work 
> tomorrow, bundled up.
> 

The fact that your supply pipe is only warm and your return pipe is cold 
suggests a coolant flow restriction.  If the heater core itself is flowing 
freely then check the supply and return paths.  The supply is pretty straight 
forward.  It is a valve that screws into the head.  Try back flushing that 
with the hose. The port in the head may be clogged with schmutz or the valve 
itself may be blocked.

The return is a thin walled pipe.  If it is failing it will leak straight 
away.  But stainless steel replacements are easy to come by.  The valve is 
also easy to come by and both are easy to replace.

Dave