Top Hose doesn't get Hot

[Martin Mc]

Odd one this - my 480s is currently off road in my garage. I've been running it occasionally to check that all is working but have noticed that the temperature gauge never registers more than a slight movement, and that the top hose on the engine never gets hot. I;ve changed the thermostat, thinking that would be the problem, but no - the top hose stays cool even if the engine is run for 15 minutes or so.

The expansion tank stays at the same level with the coolant moving if the top or bottom hoses are squeezed. Coolant in the expansion tank stays cool.

I'm going to change the temperature sender (blue sleeve) from the top of the cylinder head this weekend, as that might also have something to do with the lumpy tickover.

Other than that, I'm a bit stuck - any ideas?

[Alan 480]

Takes a long time at idle to get the top hose warm, I assume you mean the one from under the dizzy?

compare it before you start with after a ten minute running, you should feel a difference.

Personally I'd turn the engine over with a spanner or put it in fifth and rock it backwards a few feet, then into neutral and move forward, then repeat to stop from sticking.

also useful to put it into gear and press clutch and repeat, this stops the clutch from sticking

done this with the SS1 each winter