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08/22/2005

  Cosworth Coolant Leak

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Vehicle Ultima 2.9 24V Saloon
Year 1994
Mileage 91,000
Contributor Mike Walsh
Problem Gearbox not engaging, Misfire, damaged wiring loom, water leaks
Cost a 4 figure sum :(

I am not sure how this started now but the car was loosing coolant at a rate of about 1 litre per 1000 miles. If you were only driving low mileage s you might not notice too much but at the time I was doing nearly that much each week on business.

Fords in Matlock suggested a radiator cap initially which I purchased. I noticed that the old cap had two rubber 'O' rings and the new one only one. Their solution ..take the second ring off the old one and put it on the new one!

This of course did not cure the problem

Around the same time, I am not sure now whether it was before or after the start of the leak, someoneís Grandad (well someone must like him) reversed into the side of the car in a local car park and bent the rear nearside door. Insurance job .. the car went to a Vauxhall dealer for repair, as they were the approved garage as far as my insurance company was concerned. They did the bodywork ok but could not restart the car. They bought in a specialist auto electrician who traced it to faulty wiring shorting out on top of the engine between the heads. You can see the photo below of the damage.

So I decided that I could live with a water leak. I had it pressure tested by a local garage and also Lathams , a Ford dealer in Belper. No leak found, I donít think they tested it when cooling, cold or not running however .

This leak has stayed about the same for nearly 3 years!! During this period the Auto Gearbox oil all poured out and pipes rusted through due to sitting in dirt in the belly pan . New pipes were made up by local garage and we left the belly pan left off for a year although it has now been refitted.

I had it pressure tested again and I am sure the garage put the water pressure up too much because the radiator was then swollen but not leakingÖ so a new radiator was then fitted. Still had the leak!

Gearbox problems
The next issue that came along was one morning the gearbox would not change smoothly. After a few minutes the problem went away. This would happen occasionally but was worse in the winter if the car was left for a few days and it was cold and damp.

Over the last year it has got worse and worse and is now solid Ė it  was intermittent up to Christmas.

Original symptoms, refusing to change gear properly leaping about from one gear to another, when about to change from say 2nd to 3rd, it disengaged, over revved and then engaged with a bump.

Also the gear lever has to be moved slightly beyond the required position to engage correctly. E.g. just past drive and then let it move back to drive position, or just past reverse (from park) and then let it settle in reverse position.

The problems used to clear up when car warm and dry (up to Christmas 2001) and mainly occurred when the weather was cold and damp. Lathamís of Belper again checked the car and replaced the external speed sensor (Summer 2001) and changed the oil in the box, but they did not change the filters saying something about bits might fall out of the box!! I am not sure I believe this.

When the car had the intermittent problem the Speedo would read mainly zero and then flick about zero to max, the variable power steering would go between no assist and max assist at the wrong times, and the o/d light would flash.  All the symptoms would slowly clear as it warmed up and sorted itself out.

Problem is now continuous and first and reverse will hardly engage at all. If I put the box into second gear it will engage but the engine typically cuts out, this may be due to the misfire, or not, I just donít  know.

Misfire problem .
This has only occurred since December 2001. The car usually  misfires within a minute of start-up. I have noticed that a cable has been rubbing on the power steering pulley  and is partially worn through. I donít know what cable that is.

Diagnosis
With the car not engaging gear and the engine misfiring and cutting out as soon as I tried to get it into a gear  and move  it I had very few choices as to what to do. After chatting with various people on the web site I decided to trailer the car to Meteor Ford in Birmingham. The senior mechanic there, Stan is a fully trained Scorpio and FDS2000 WDS person, in fact one of the first master technicians on the Scorpio in the UK. His son was on the 24v inlet design team and his sonís boss was something major in the design / management  of the Scorpio 24v engine. So anything Stan doesnít know he can find out very easily. I have spent a couple of hours chatting with him, a genuine bloke and good mechanic.

 

The first thing was that the FDS system was telling him that the gearbox selector switch was faulty and had to be replaced. He called this a ďpringleĒ switch. It is a variable resistor device at the bottom of the auto select lever. Pringle? Arenít they crisps or something. Well it just means Park Reverse Neutral Go Low!

To replace this meant all the error codes in the EEC-V would be lost. Never mind I was sure the car would generate loads of them straight away again!

PRNGL switch was replaced, the old one was badly corroded and damaged and could not be removed without breaking it.

This time the FDS was showing all kinds of strange codes, e.g. in gear when in Park etc and Stan was suspicious of the wiring.

He asked me what had happened to the battery cover. I was not aware of ever seeing it. He said this was very important, in heavy rain the water pours through the heater grill at the base of the windscreen and down onto battery, fuseboxes and relays as well as the wiring. See picture on the left.

First of all he checked the wiring on the front cross member at bottom of radiator, see picture above. Fortunately this was OK but often has water in the wiring and apparently antifreeze will corrode the insulation.

Then he took off the  top engine cover and stripped off inlet manifolds, fuel lines etc. What he noticed when moving the car was coolant rolling off the back of the engine and down around the gearbox. With the inlet manifolds off it all became apparent.

There is a coolant manifold running between the heads at the front with a metal pipe that goes back along the V between the heads and round the back of the engine to one of the heater hoses. There is also a rubber hose off this manifold that goes across the front of the nearside head and joins a pipe to the radiator or thereabouts. Anyway both of these were leaking at their connection to this manifold between the heads. This meant the top of the engine between the heads was soaking in coolant with antifreeze. What runs along the top of the engine in this location? The engine / gearbox / PCM wiring loom!Wiring loom damage between the heads

Splitting the loom casing open showed lots of soaking wires with perished insulation.

See the picture on the right for wiring damage and at the bottom of the page for the manifold and pipes. The other picture at the bottom I have lifted from elsewhere as it shows the wiring loom coming out between back of heads and going down to the gearbox. It also shows the metal coolant pipe to the heater coming out between the heads.

Work on the car has not progressed for a couple of weeks as Stan has decided the loom is too badly damaged to repair and is waiting for a new one. Several have already been sent by Ford Parts but they have been wrong, including a couple from Germany. Hopefully the correct one will arrive soon.

Clearly any coolant leak must be tracked down and solved is the main lesson so far. The damage done by antifreeze on engine wiring has to be seen to be believed (as do the amount of wires that Ford used in their looms!)

I will provide a further update when the car is finished and hopefully the gremlins go away when the loom is replaced and the leak cured. But perhaps there are more problems waiting to reveal themselves as we peel this onion. It is a strong one and is making me cry and hurting my wallet !!

Update as of March 2002.
Installing the new loom and manifold and pipes has done the trick. Initially he water pump was leaking some water but this stopped after a couple of hours running, apparently caused by being dry for a month or so. The next issue was that when on the ramp a drop of blue water/antifreeze could be seen on the engine oil cooler that the oil filter screws into. Checking the water pipes above showed they were dry so it was the unit itself. £120 from Ford. The pictures below show the position viewed from below looking to the front, the mounting for the unit, and also a picture of the old and new units. The old unit was leaking at one of its seams.

So all leaks cured, car running well, I have now wire brushed and wax oiled the underneath and I am repairing the sunroof, weather permitting. The gearbox has not put a beat wrong since.

An expensive lesson learnt!!



 

 


 
 

 

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