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  Replace 24v T'Stat

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Coolant Leaks
Replacing Radiator
Cosworth Coolant Leak
Ballooned Radiator
Coolant Fans
Replace 24v T'Stat
Cooling Manual

Vehicle Cosworth  24V engines only
Year All
Mileage All
Repair Cost £70
Repair Part(s) Thermostat [Oil Press Switch]

The thermostat on the 24V was a mystery for some time.  The workshop manual mentions that it is inline with the bottom radiator hose - but this is for the BOA (Granada) Cosworth engine. Finally, we found it - it is a bypass design mounted externally behind the AC compressor pump mounting on the nearside of the engine.  It circulates water around the cylinder heads first, and then admits the coolant to the radiator when sufficient temperature has been reached.

The symptom of ballooning radiators has been much discussed on the Forum and the Mail List and current advice is to change the thermostat if the radiator becomes faulty through this cause. Baz, a member on the Forum has recently changed his thermostat and these are his instructions:-

Notes from BAZ

I finally got round to changing the thermostat on my Cossie yesterday, more due to need than want I hasten to add!!

The rad I fitted late last year finally gave up when the seal around the top auto pipe connector cracked and started flushing water at an alarming rate!! I had another spare rad and a brand new thermostat so I jumped into the car and zoomed off to my mate’s garage, where a suitably cleared ramp would make things so much easier!

Unfortunately I never took my camera, but the job is pretty straight forward and went as follows:

• Remove the under tray (4 x Torx 30 bolts)

• Disconnect the two auto fluid pipes and seal the ends to stop too much fluid loss.

• Drop the oil cooler from under the front cross member to allow the rad to come out easier.

• Drain the rad by either the drain plug or the bottom hose

• Disconnect the two fan plugs

• Undo the two retaining bolts and drop the rad out of the bottom of the opening

The removal of the air con compressor is necessary as the thermostat sits between the compressor and the engine block (a masterpiece in design!!)

• This is done by first removing the belt tensioner by removing the two bolts holding it to the aircon compressor bracket

• Remove the belt (I actually replaced this as the old one looked a bit worn)

• The 4th bolt for the air con compressor is behind the tensioner.

• Remove all four bolts and carefully drop down the compressor. (I then tied it up with a piece of wire just in case)

• Now because the hoses have been attached to the thermostat for so many years, they are a bit of a pig to remove, but a little gentle persuasion with a large flat blade driver does the trick (after first removing the hose clips!)

• The stat is then replaced with the new one (£45.00 and a six month wait from Fords!)

Now at this point, I noticed a wire dangling and as I hadn’t unplugged any down there, panic set in. It turned out to be the cable to the oil pressure switch which is also in a masterly location: behind the thermostat!! And when I had been removing the stat, I had broken the top off! Now it was 5:25 in the afternoon, but my mate who owns the garage, got on to his local supplier and within half an hour, I had a new oil pressure switch, new belt and a new water temp sender as well (because we weren’t quite sure what had actually broken!)

The switch was replaced followed by the stat, the compressor bracket and the belt. Next on was the belt tensioner and then all tightened up!

Replacement of the radiator is the reverse of the removal. The system was topped up with coolant and the auto fluid topped up as well. It is at this point that I realized that the radiator I had was not perfect and the leak from the drain plug bore testament to this! However, the system eventually sealed itself and has been run all day today with no real problems. I am going to invest in a new radiator next week though and fit it all over again.

Apologies if this goes on a bit, but imagine how much there would have been with photos! Just to make sure I don’t ever run low on water again, I have started to fit the level indicator out of an earlier Scorpio but the later ones like mine don’t even have the LED in the dashboard so I have some soldering to do as well! Also, if someone with access to the wiring diagrams (mine are at work) can tell me which pin the white/green indicator wire goes to for the coolant level indicator I would be grateful

The work was all done on my mate's ramp in his garage and would have been a lot more work without this. The whole job took about two and a half hours.

Thanks to Baz for those notes.




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