Air con failure and rebuild

[Martec]

Hi,

This is the story of the A/C on our MY2000 petrol V6, we bought it 4 years ago and it has needed an engine out job, rear subframe removal and refit with new subframe mounting bushes, all new brake pipes and now the A/C. This will only be of interest to those that do their own repair work!!

It was regassed about 4 years ago, then 1 year ago and then 3 months ago. The garage said they would not regas it until the leak was sorted, so they added a dye and some nitrogen to build pressure to run the pump and found a sizable leak on the drivers side of the engine and on a pipe close to the compressor.

So not the expected condenser (gravel rashed and often holed), or the compressor, but pipes??

A basic over view of the A/C system is needed here:- the large unit in the car behind the dash contains the heater unit and the A/C evaporator (chiller). There is a connection behind the engine for the hp and lp pipes (on a manifold), these run down the drivers side of the engine to another set of connections. One pipe section runs from this connection (lp) across to the manifold on the compressor and the hp pipe to the condensor (a radiator in front of the water radiator). Another hp pipe runs from the condenser back to the connection beside the engine via the drier.

You buy them as 3 pipe sets and 'O' rings for the manifolds, I bought 2 pipesets, from behind the engine plus across the car to the compressor and a few 'O' rings form Marshalls of Lincoln. They could not tell me the procedure but that the back of the engine is called the 'bast--d pipe!

The procedure I discovered is as follows:-
remove the windscreen wipers,
remove the plastic cover below the windscreen
remove the steel crossmember
remove the 4 screws to the wiper motor so it can be moved around
remove the front plastic cover (above the headlights)
remove the rubber inlet pipe between the air filter and the inlet manifold
remove the inlet manifold (cover the 6 inlet ports and the hole for the CC breather)
remove the heat shield over the drivers side exhaust manifold
on the drivers side remove the rear heater pipe bracket (a dremel was used to remove the pop rivet) and then snap the bracket in two
unbolt the front bracket (this allows the pipes to lifted as necessary)
remove the pipe clip on the A/C pipes beside the exhaust manifold
From under the car remove the small plastic cover (drivers side)
unbolt and remove the hp connection
push off the clip and pull apart the lp connection (special tool needed) (I cut the pipe as both were to be replaced)
the hp/lp pipe clip can now be unbolted
on top again, at the back of the engine unbolt the manifold to the heater/AC unit

The double pipe and manifold can now be wriggled out ( I finally removed this pipe set with the manifold on but didn't even consider putting the new pipe in until I had removed the manifold).

With the new pipe set loosely in place I fitted the new 'O' rings after dipping them in fridge oil and refitted and bolted up the manifold.
The pipe brackets can all be assembled and fitted plus the heat shield, wiper motor and inlet manifold.

From underneath the manifold on the compressor can be unbolted and the lp pipe clips across the car released. from on top the connection to the condenser can be released and with the AC pressure switch connector and the fan connector released this pipe can easily be wriggled out and replaced (again fridge oil on the 'O' rings first). The brackets and manifold can be reassembled and the two parts of the lp pipe clipped together and the hp pipe bolted into place.

With everything back in place it can then be taken for evacuating to remove moisture and regassed.

............................or you can protect the pipes NOW so as not to have to do this sh1tty job.

Where are the rust holes? on the underside of the hp (small bore pipe) beside the drivers side exhaust ( there is a drain hole here that allows road muck to enter the engine bay through the inner wing with the hp pipe in the way!) and on the exposed steel pipes on the manifold on the compressor.

Jaguar have this job down as 1.9 hours!!!???? but at £125 plus vat, it took me all told 3 days of steady work and 2 to recover, fingers crossed for gassing up, but I have found the holes so no guesswork. This is apparently common on older S types. Total cost with dye test, pipes, 'O' rings and gassing up, about £560

All the jobs done so far should give us many years of enjoyment of a rather nice car at a very cheap price!!

Brian

[J44EAG]

Well done, Brian. Quite an epic.

Mike

[Martec]

Thanks Mike, as you can imagine it didn't go quite as I wrote it above. I released the wiper motor as I thought the power cable was in the way.......it wasn't but I used this oportunity to connect my spare scrapyard motor and found it OK. Then I refitted the motor only to have to have to release it again later!!!!????

I went through several dremel grinding wheels as I couldn't see the pop rivet and had to use a mirror. If I had had the sense to remove the inlet manifold first it would have been so much easier and clearly seen.

With the inlet manifold removed the pipes literaly fell into place. I was luck that the three bolts holding the exhaust manifold heat shield came loose with plusgas assistance.

When refitting the inlet manifold I was very careful of the 8 long ang short bolts holding on the manifold into aluminium and plastic and the snapped the plastic water 'T' piece ontop of the engine. I remembered that someone else had resolve this problem with a copper 'T' piece and pipe tails. I finally found a plumbers merchant to supply the copper only to now be concerned I may have been snapped by a speed camera passing a school at more than 20mph.

I'll not mention the oil dribbling on me from the lower lp pipe

Still the joys of achieving a job done rather than paying an apprentice to learn on my car as my dad always said!

Brian

PS the next job to look forward to is building an engine for a friend, BMW bike head onto an 'A' series engine, I've always fancied doing that, its the reason I fitted the Mondeo head to my 'B' series engine.

[oldtimer]

What Oh Martec,
As usual, a good read ------ Sounds a piece of cake the way you have written it but I'm sure there where plenty of expletives along the way. Of course the elapsed time to completion gives an indication of the work involved . The total cost of about £560 without any labour is still quite a considerable sum ---- well it is in my book.

I take my hat off to you Sir, very well done
P
PS Must examine those pipes on mine !!!!

[Martec]

A few interesting things have occured which I hope others can help with:-

Last week we went to spend a great day out with 'Oldtimer' and noted that his 2003 car does not have the same pipe route of the air con gas pipes, so it seems only the pre-2002 cars will suffer my position of corroded pipes.

Due to the hot and stuffy conditions the air con was in use, but it became evident very quickly that below certain revs (approx 1200) the compressor declutched and we started to steam up. So those who got too close (in the boot) enjoyed our exhaust fumes at 1500 revs (I had to keep the revs up in the queueing traffic). Is this normal on the older 'S' type? we don't have such traffic queue up our way!!

Also I suppose it shouldn't be in here, but due to leg aches I've been using the cruise control (never had one or used it before), is it acceptable to raise and lower the cars speed with the + and - so as to keep a good distance from the car in front, or does continual use of these controls harm anything?

Look forward to your comments,
Brian

[J44EAG]

The short answer about cruise control use as you describe is "No". No harm is done at all. That is what it is there for.

I have a back condition which affects the comfort of my right foot. Automatically now, I use a combination of cruise and foot control. I use the CC as often as I can in my attempts to keep foot use and pain to the very minimum.

Cruise control has been a feature on every Jaguar I`ve owned over the last twelve years. I`m pleased to say in that time I have never had a moments unreliability using the system which in my case probably accounts for more than 50% of my driving time behind the wheel of a Jaguar.

I recall a journey that was about to be made a few years ago in my parents 1600 auto Focus thing. After just a couple of minutes driving I found I loathed the contrivance and for just one reason. No cruise control fitted! With the prospect of having to drive over two hundred miles in it that day, I refused to drive it any further and turned the car around and returned to the house. It was then all change under huge protest due to being forced to change horses so rapidly. The journey recommenced in my hard as nails old S-type V8 fitted with my beloved cruise control. I`ll never buy another car without it! Not negotiable!!

Mike

[Martec]

Thanks for that Mike,

As to the AC compressor clutch control, I looked on the workshop manual and Technical guide for 1999 on cars, nothing but on 2003 Technical guide I found this:-

I tried to attach a paragraph from the guide but basically is says the engine control module controls the compressor clutch with a request from the climate control module. If the ECM detects 'idle mode' or overheat?? then the clutch is disengaged.

It also says the humidity is condensed onto the AC evaporarator (in the heater unit behind the dash) and it runs off through the common drain.

Having looked at a spare heater unit the drain is quite small and I assume this water may not help the steaming up of the car.
I had hoped to find something to to say that at 'idle' with the AC on the ECM would raise the engine speed to carry the load of the compressor cutting in, but nothing at least on early cars or slightly later ones.

On a slightly different tack I very much appreciate the heated front screen on our 'Focus thingy shopping trolley' and a salesman recently stated that only Ford seem to do that??
I looked at the relay and fuses of early cars and there is a place for the extra relay (the fuses are already in, but would need bigger ones)............So if the wind screen got damaged could it be replaced with a later heated screen??

Brian

[J44EAG]

Can`t read this, Brian. Just computer gobledee gooke!

Mike

[Martec]

Thanks for that Mike,

As to the AC compressor clutch control, I looked on the workshop manual and Technical guide for 1999 on cars, nothing but on 2003 Technical guide I found this:-

I tried to attach a paragraph from the guide but basically is says the engine control module controls the compressor clutch with a request from the climate control module. If the ECM detects 'idle mode' or overheat?? then the clutch is disengaged.

It also says the humidity is condensed onto the AC evaporarator (in the heater unit behind the dash) and it runs off through the common drain.

Having looked at a spare heater unit the drain is quite small and I assume this water may not help the steaming up of the car.
I had hoped to find something to to say that at 'idle' with the AC on the ECM would raise the engine speed to carry the load of the compressor cutting in, but nothing at least on early cars or slightly later ones.

On a slightly different tack I very much appreciate the heated front screen on our 'Focus thingy shopping trolley' and a salesman recently stated that only Ford seem to do that??
I looked at the relay and fuses of early cars and there is a place for the extra relay (the fuses are already in, but would need bigger ones)............So if the wind screen got damaged could it be replaced with a later heated screen??

Brian

[J44EAG]

My early model V6 SE had a heated front screen. I imagine it linked to a wiring loom that was standard to all models of the period and included the relay. Retro fit on a model not originally fitted with the heated screen should I suppose be fairly straight forward. Add the relay and grab a switch panel off an early breakers yard SE car, fit a fuse and all should be go. That`s how I see it, Brian.

My later V8 was non SE spec. No heated front screen, door mirrors or seats. That car used to steam up on occasions and not having the SE spec was a pain. Again retro-fit from a donor car, those additions should all be possible with the right salvaged parts.

The pre-facelift and facelift cars were markedly different in so many ways to the early cars. That extended to all services in the car. Essentially the pre-facelift cars were completely different animals to the early models so a degree of caution might be needed if trying to fit new wine in an old bottle...so to speak.

Mike