Temp gauge / thermostat.

Hi All,

I have searched the forum and come up with a few answers but i hope someone can help with my own symptons.

The temp gauge is rather erratic. Sometimes it doesn't even move, other times its fine and will rise normally. Sometimes i have a nice warm interior, other times it wont even heat up in there. If i give the top hose a couple of squeezes it usually gets the temp gauge working on the dash.

Is this a case of replacing the thermostat? Do you think the current stat is stuck open? I am quite comfy working on cars but i have never changed a stat - is it a simple DIY.


I want to thank you guys in advance for your help. I can imagine you get a little ****ed off answering the same questions over and over.

Been researching today 'cos got problems myself and hoping not HG.

Might have found answer to your problem, air or air locks in the cooling system. Need to bleed the system. If got Haynes, look at 1A.15 or maintenace procedure for every 36k miles. Hope it helps. Chester

unfortunatley i dont have a haynes manual, but i am going to replace all the coolant anyway. when i had a Rover 25 i did it the following way -

Removed lower hose in rad,
Drained all Coolant,
Flushed through with my garden hose.
Refilled with coolant and water mix (How Many litres? - I cant remeber)
Satrted car up and let it warm up, giving it some revs. i then let the car be "sick" Out of the coolant tank (if that makes sense?)

Is there a better way? would it be worth just changing the stat whilst im at it?

The temperature when sitting at idle sits normal but when i am driving the needle goes right down low, then at idle again it sits normal, then driving it goes right down low - you get the picture.

Will having the system bled cure this?

How long does it take the engine to warm up from cold?

Sounds like stat is fully open or no stat at all?

its really hard to tell but its ages.

Also the car self revs rather around 2000 RPM on its own for quite a while.

Your temp. gauge should move to mid position within a mile or so of starting, and the heater should start working at aboutthe sametime. If it takes a lot longer then as NI saysthe stat has probably been removed.

Stat is stuck open then.

You might need to reset the throttle position sensor TPS.

Ignition to position II with dash lights on
Push throttle fully to the floor 5 times in succession, switch to position 0 again. Then start.

Switch the heater fans off, which will allow some engine warming.
Edit - not sure why the stat sticks after time, I believe the wax leaks out preventing the ram/plunger from retracting again.

The diameter of the stat opening is 28.5mm, with an opening of only 6mm, anymore than this can increase the flow enough so overcooling takes place.
I've done a lot of messing about with the stat in the FL1



Given the hols are coming, chances of getting a stat are slim, and you don't want to taking the coolant arm off during the queen's speech
you could cover part of the grill with card or HD plastic film, giving less air flow, don't cover all of it, leave the lower valance part open for manifold cooling.
That way you'll get to pick the mother inlaw up for xmas dinner