Is this a special one unique to this car and not just another thermostat?

 

4wd is unique to 4wd as it is sort of two stats in one, totally different from 2wd cossie.
tabetha

 

Thanks Tabetha, that may be the answer to my problem. Does anyone have the Ford part number so that I can try to get one here first. If not where is the best place in the UK to get one.

 

bought mine off MSD having bought 2 others from other cosworth suppliers and having issues with them not opening correctly

http://cgi.ebay.co.uk/Ford-Sierra-4w...742.m153.l1262

 

The one on MSD website looks identical to the one I have just put in. My problem is that when I get up to highway speed you can watch the temp gauge go down to cold, its that quick, have put in 3 stats just in case, flushed the cooling system twice, tested the head gasket, bled the system of air 4 times, checked the water pump and it still does it. Going to set fire to it on Saturday !!!!!

 

As long as it opens at 88 degrees centigrade, you're fine You might also have an over sensitive coolant temperature gauge sender.

 

Forgot to mention I changed the coolant sensor, also the heat coming out of the heater reflects the temp reading. !!!!!!

 

4x4 cossie stats are notoriously unreliable, before fitting its advisable to drill a small 3mm hole in them in case the stat ever jams shut which they do, also the temp gauge on the dash is pish, my one used to go up n down more times than a hoes knickers, worth getting a decent water temp gauge and fitting it


Luciano

 

I have already drilled the hole so that the air bleeds out better. Do you mean get another sender from another brand or relocate the sender somewhere else.


How often does a hoes knickers going up and down Ha Ha

 

Get yourself a SECS monitor

 

All stats are a pain in the a**e, they always go duff, bosch is working on a totally electronic engine temperature control system.
It baffles me why nobody has yet made a electric valve that simply opens shuts as necessary as the stat does, sorry is meant to.
tabetha

 

What worries me is that if the engine is running at a cooler temp than it should the ECT sensor will be putting in more fuel as it thinks the engine has just started and is still warming up. Secondly over here if you don't have an efficient heater in the winter it can be life threatening at -40C. The car will ice up on the inside BIG time then you cant drive then you freeze to death. Its like batteries, you dont have one that is iffy or on the blink, you get a new one or its curtains.

 

Wish I could afford one!

 

if it really cold over there at the moment you can fit a 2wd thermostat in a 4x4 thermostat housing this would mean you would get warm air straight away from the head going into your heater matrix, and then the stat would open up once engine has reached it running temperature

you shouldn't find any enrichment from the ECT if it doesn't drop below 60deg and i'd be shocked to see it drop that low when running

 

Its not cold here yet its still 8 or 9 C above freezing so when it does come it gets real cold immediately like someone switched on winter. I have tried 3 different types of stats but with no success it gives the impression that there is no circulation but never overheats. I'm going to try blanking off the radiator and see what that does but I shouldn't need to at this temp. What is the difference between a 2wd stat and a 4wd stat I cant get my head round it. Another thing is why is the stat in the bottom rad hose not the top hose like any other car. To my mind the cold water returning to the block would close the stat.

 

Afaik, the stat is in the top rad hose, on 4x4, and goes top the rad top connector just under where the std i/cooler is, the bottom one runs from the rad to the angled pipe on the water pump pointing downwards.
The main difference is the 4wd stat has a little extra end bit which is another valve which blocks off another circuit, the 2wd stat is just a normal stat single type one.
tabetha

 

I'm running a 88 degree thermostat with no problems at all.

 

I got a 88C in my 2wd, which runs at around 73/76, but the 82 ran around 78/83!!, I find if I were to let it warm up so it gets really hot it stays like that for the rest of the day, but otherwise stays lowish, on the gauge anyway.
Doesn't help with the heaters being so crap either, me other half has astra, that is like a furnace compared with cossie, even in snow ice conditions don't have temp turned up full, and fan on 1.
tabetha

 

Both my cossies 4x4 have the stat in the hose that leads to the bottom of the rad on the right side of the car

 

eh well it shouldn't your not fitting the thermostat incorrectly are you and placing inbetween the head and the housing as if this is so its wrong the stat goes in the housing with 3 bolts (on the front) that has the hose connector pointing towards the left (if looking at if from the front of the car) 'inless we got our left & right mixed the wrong way round'

The 4x4 stat is a 2 stage item that also controls the flow into the heater matrix that's why you'll find as soon as you start the car you should have warmish air within 20-30secs, plus if you leave the vents control pointing towards the windscreen the fan always blows to keep it from misting up (I may stand corrected on this yet)

 

I know the correct place for the stat but if you follow that hose going to the left from the stat housing (looking at your picture) it goes to the bottom of the rad and if you follow the one to the right of the stat it goes to the top of the rad tucked in below the intercooler which as I said cannot follow the logic cooler water returning to the block via bottom hose only to meet the stat where it will close cos its cooler.

 

Stick a bit of cardboard in front of the radiator lol.

 

Tried that I've blocked off 3/4 of the rad but no difference. I am leaning towards the water pump impellor disconnecting itself from the drive pulley. Anyone had this happen?

 

have you bled the system properly? sounds like there is not enough water in there. when stationary it will get to temp as there will be enough water in the header tank. when running at speed the first thing to suffer is the heaters if there is not enough water in the system as it flows round. fill the cooling system until water flows out of the of the bolt hole on top of the thermostat housing & then leave running with the header tank cap off for about 10 mins occaionally holding the engine at higher revs.

 

This is because the later (89 >) Sierras had a modified heater control lever, which had an additional switch that interrupted the power to the blower if the lever were in the 'off' position. Even with the blower dial set to 'off', the blower would still run but at a low speed if the air flow lever is set above the lowest position.

 

I've done that too, I left it until the fans came on and off twice though the fans did seem to be on a long while.

 

have you flushed the heater matrix?

 

No, because I don't have an actual heater problem, when I drive in town stop start etc. the temp comes up to NORM and the heater works. When I drive out on the highway 120 kph the temp gauge drops down to cold, you can watch it do it, and then the heater reflects the temp gauge. Hope that explains it.

 

So when the control is set to hot the heater temperature goes colder along with the temp gauge going down while you're going along at 70mph...

How odd It's almost like the coolant is being cooled too well.

 

You got it the faster I go the cooler it gets and now running out of time as winter starts next week, you can set your watch by it!!!!! I still think its a flow problem, still suspect the pump, trouble is you cant poke something in the pipes to see if the impellor has dropped off or what ever, only thing to do is take the pump off with that nice little dumpy hose to get off. Fix Or Repair Daily think I'm going to get a Bimmer M5 (E39) cos I hear such good things about them on here