Cool heater in the cold weather

[A900ss]

This is my first winter with the tvr so I may be expecting too much but my heater is very cool when moving.

It warms up nicely when I get to some traffic lights but anytime on the move, it's cool. It certainly made the roof off driving today less pleasant than normal.

I know the temp gauges on these are renowned to be useless but on the move (single A roads) it is reading about 60 degrees, sometimes lower. The same driving in the summer was 75/80 ish degrees. When I get to traffic lights and I feel warmth coming from the heater, the temp gauge has moved to circa 70 degrees as the car isn't moving in the cold air.

Reading the forum it looks like the heater does cool a bit on the move but they are still normally effective. Likewise 60 on the move seems too low.

What is the best way to check if the thermostat is stuck open without actually taking it out?

Any other thoughts most welcome.

(PS - I don't suspect an air leak or the heater valve as the heater does get hot when the car isn't moving)

Edited by A900ss on Saturday 23 November 16:22

[A900ss]

QBee, mine gets warm at the traffic lights but then cools down (heater and temp gauge) when moving again.

PS - I checked my swirl pot just in case and it was full to the brim.

[A900ss]

I assume the test is to hold the top hose and feel if it warms up slowly with the engine (thermostat stuck open) or gets warm suddenly (thermostat working correctly).

[A900ss]

What's the process for bleeding?

[A900ss]

Just started her from cold and then held the top hose to see if it got warm very fast (as in thermostat just opening) or warmed up gently (as in thermostat stuck open).

Hose warmed up gently and even when it was warm, water temp gauge still hadn't moved from bottom.

Looks like my thermostat is stuck open.

[A900ss]

The fact that my top hose warms up gradually rather than a gush as the thermostat opens suggests to me thermostat or does an air lock also show those characteristics?

[A900ss]

I'm replacing my thermostat this weekend and can somebody give me a heads up on how long to do and what involved?

I've just read a piece that suggested removing the dizzy and removing the serp belt. Is all that really necessary?

I was just hoping to remove dizzy cap and that would be enough room (or am I deluding myself?)

Thanks.

[A900ss]

Well the old thermostat is out and is defo stuck open so that's good.

The bad is that 'a well known' TVR parts retailer sent me a thermostat that isn't a big bore thermostat so I now need to wait until tomorrow when the correct one should arrive in the post.