Coolant temperature

[Charles Farran]

Dave,

Like Vic,

I only think you need to worry if the coolant level in the expansion tank has fallen.

The hand book says "if ccolant is not displaced or the level in the expansion tank has fallen appreciably since the last periodical check,a leak in the cooling system or overheating must be suspected". Only then dose it go on to talk about topping up.

When cold, if you look at the relative heights of the thermostat neck & where the expansion tank pipe outlet at the top of the radiator are (at least in my car) more or less the same, so when the system is cold & not under pressure the level of coolant in the thermostat neck should be the correct / constant level. When the system warms up & pressurises & vice versa coolant will flow to & from the expansion tank.

Also as your fan kicks in & out then that suggests the correct level of coolant is in the system overall. Many years ago when i had a radiator failure (or was it the water pump?) & rapid ccolant loss , my temp gauge did not register at all & neither did the fan cut in. I was lucky to get away with it as i stopped pretty quickly realising something was wrong & got away with just replacing the radiator.

If you haven't got a leak anywhere then i believe you shouldn't have anything to be concerned about.

Cheers,Charles

[Vic Butler]

I checked the level in the expansion tank and despite the overheating problems previously suffered it's still half full or thereabouts. I didn't check the level under the thermostat housing plug.
I retarded the ignition a fraction in readiness for Monday's road test.

[Vic Butler]

At a local vehicle show today there was a rubber bumper B with the bonnet up. The expansion tank pipe had the upward loop and as best as I could do I reckon the top of the loop was just below the top of the brass plug on the thermostat housing. The brass plug though was taller than standard so I reckon with a correct plug it would be level like mine so it appears that the highest point of the pipe should be on a level with the top of the plug.

[Dave Wheatley]

Took the car to the Kircudbright classic car show today. Very warm, and busy with traffic and punters in the show car park. Temp went up to almost danger level on the gauge, and the fan spinning merrily. After parking up and leaving for half an hour, I checked the expansion tank - half full as always. Round trip 100 miles, accurate guess 33 mpg.
After talking to the other 2 B drivers there, it appears that the cooling cycle is normal - very swift rise on the gauge in traffic jam conditions, but the fan quickly takes care of it.

[Vic Butler]

Nothing to worry about then Dave.