2wd Sapphire Cosworth Heating / Cooling

The Ford Sierra Cosworth Cooling system is a traditional setup found in most cars and is very similar across the cosworth range it basically consists of the following main items:

-Radiator
-thermostat
-waterpump
-header tank

It circulates between head , block, radiator and turbo through various hoses

The two rear wheel drive Sapphire Cosworth's that I have owned have had problems with the heating / fans when I first got them. In short for a standard 2wd Sapphire Cosworth:

-fan wiring is inadequate
-not enough relay's for the fans
-not enough fuses for the system
-thermostat could be replaced with a lower temp one
-fan switch could be upgraded to a higher temperature switch if aluminum radiator is used
-end tanks of radiator prone to collecting sludge

With my 2wd Sapphire Cosworth at the moment I have a standard radiator that I have just had re-cored about 6 months ago.The radiator was filled with sludge and leaking from the previous owner who had used also used 'Bars' head gasket leak etc on it . With limited options in New Zealand , I opted to have it reconditioned. The internal core was not able to be cleaned out as the waterways are spiral I was told. I had the end tanks cleaned and fitted to a new core.

The benefits from going down this route is that I firstly didn't need to wait to get a radiator imported and that the standard radiators do not get heat sink like the aftermarket alloy radiators do.
If upgrading your engine it is obviously recommended that you upgrade your cooling system at the same time though.

One of the radiators I had was accumulating debris beside the fan switch within the end tank. Because of the shape of the tanks it is prone to collecting unwanted sludge. If  your having problems you can just stick a object in the fan switch hole with it removed to check the extent of it.

There is aftermarket alloy radiators fan switches available that come on at a higher temp to take into the account the heat sink from passing through the alloy. They are available from all the main UK suppliers.

Check out some links below:

(http://shop.motorsport-developments.co.uk/uprated-ford-sierra-cosworth-fan-switch-131-p.asp)
(http://www.burtonpower.com/fan-temperature-switch-88-77deg-sierra-cosworth-m22x1-5-xefs92.html)

91 Deg C and Off again at around 87Deg C

-The uprated fan switch comes on / off at 91/87 degrees.
-The standard fan switch comes on / off at 88/77degrees.

91 Deg C and Off again at around 87Deg C

91 Deg C and Off again at around 87Deg C

91 Deg C and Off again at around 87Deg C

The fan circuits on the 2wd Sapphire and the 2 door cosworth's are single fuse / relay, and are prone to burning out. The later model 4wd's had twin relays to remedy this. And if you haven't already updated your's I suggest you do. There are aftermarket fan loom kits available on Ebay or direct from the likes of CW-loom or Motorsport Developments all ex UK. You can replace the fuses but after a while it will melt the fuse holder / fuse box housing, and I have read of other owners having other fuses and wiring close by also getting damaged.

(http://www.ebay.com.au/itm/Ford-Sierra-Rs-Cosworth-Cooling-Fan-Rewire-Loom-/270996701600?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3f18a981a0)

(http://www.cw-looms.co.uk/)

(http://www.ebay.co.uk/itm/Ford-Sierra-Cosworth-Radiator-Cooling-Fan-Rewire-Wiring-loom-Sapphire-RS-/251336051552?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3a84cbcb60)


 

The standard thermostat in the two wheel drives is 88 degrees, and I have replaced mine with a 82 degree thermostat, so that the water pump circulation starts earlier. Please note though if you read the article from MSD (Motorsport developments UK) that the temperature directly affects the ecu chip map. So check with your tuner first. http://www.motorsport-developments.co.uk/tech_articles/FAF249.tech.pdf

With my cars after emptying the water system and refilling, I  got air pockets  you can leave the radiator cap off and squish the radiator hoses and wait for the thermostat to open to bleed it all out with the heater on, or on the RS forum one of the helpful contributors recommend drilling a 4mm bleed hole to aid flow in the thermostat. (http://bbs.rsownersclub.co.uk/showthread.php?t=443920&highlight=thermostat)



There is a great thread on "How to wire Cosworth fan looms"
I wont repeat the information other than the diagram. See the link below:
http://bbs.rsownersclub.co.uk/showthread.php?t=347745

On my current 2wd Sapphire Cosworth I have also added a over ride switch close to ignition so if I have any dramas I can flick the switch on without having to wait for the water temperature to heat up while driving. (I hope I don't have to use it)

The other thing to be weary of with the fan system is the radiator fan switch. On the 2wd cars it is the brown switch above. The switch is not available at any of the usual suppliers in New Zealand and Australia that I could find, such as BNT, Repco, Partmaster, Trade Parts, Supercheap etc
The switch can pack up, on my 2wd Sapphire Cosworth the fans weren't working and I got an reproduction aftermarket switch replacement from Lodge Auto centre in Hastings , New Zealand ( http://www.lodgeautocentre.co.nz/cosworth.html ) after having the radiator reconditioned I fitted the new fan switch only to find that it didn't work. I then tested it by dropping it into a kettle to test it with a multimeter on it. And it was not working as the kettle came up to boil. Disappointed I contacted the supplier back and although the product didn't work  Lodge Auto Centre quickly returned a replacement OE one. So be careful when using aftermarket parts.

Header tank cap

Standard Motorcraft screw type radiator tank cap that is fitted to the 2wd's. These are not known to have problems that I have found. Replacement ones are available from the likes of Burtonpower. http://www.burtonpower.com/parts-by-fitment-type/parts-by-engine-ford/ford-cosworth-yb/radiator-cap-screw-thread-plastic-type-fc500.html
Header Tanks  This is a picture of the standard 2wd sapphire header tank. The are prone to becoming silted up, and discolour very quickly. Most people replace them with aftermarket alloy tanks (refer to my other blog post) There is suttle header tank variations in all the Sierra range. The 2 door sierra cosworth has a water temperature sensor in it for when the fluids get low. And they are not interchangeable with the 4wd's as the turbo return is small on a 2wd and larger on a 4wd.
Waterpumps The 2 door sierras and 2wd Sapphire cosworths have the same waterpump and the 4wd waterpump and thermostat housing is different. Also be aware pinto sohc water pumps fit but are not up to the job. In terms of flow / keeping the engine cool.

Standard coworth waterpump on left, standard pinto sohc waterpump on right

Standard cosworth waterpump on left, notice thickness around snout area, and impellor flange, standard pinto on right thinner housing and thinner shaft housing

Standard pinto sohc waterpump  furthest away, and standard cosworth pump closest.

This is a hybrid reproduction water pump, it utilities the pinto sohc housing with a larger cosworth impellor / flange. And its affordable and in stock at the moment , compared with getting a standard cosworth waterpump from uk. It is however manufactured overseas.

 

Picture of part number of the Non OE waterpump part number from BNT in New Zealand

 

Waterpump to block housing gasket

4wd waterpump which has suttle differences from the 2wd water pumps.

http://www.burtonpower.com/parts-by-fitment-type/parts-by-engine-ford/ford-cosworth-yb/water-pump-sapphire-escort-cosworth-yb-4wd-rs500-epw12.html

Water rail

This is a picture of the standard water transfer rail that runs underneath the car at the front of the engine, attached to the radiator with brackets they are prone to rotting out and replacement stainless ones can be brought from the likes of Graham Goode racing etc. The water transfer rail is no longer available from ford.

http://www.ebay.co.uk/itm/Ford-Sierra-Sapphire-Cosworth-2wd-Bottom-Radiator-Tube-Water-PipeStainlessSteel-/390511982625?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5aec53f821

Fan Belts

The other items I have not mentioned are the fan belts, which are a twin system on the 2wd Cosworth Sapphires  and the usual up keep / replacement is required when they become brittle or start splitting. 

Frost plugs

And also throughout the head and block is frost plugs, and occasionally they rust out. The block ones are easy to flick out, and tap new ones in. And the head ones need to be replaced with head off and manifolds removed for access.