I just had a mini-saga with my airconditioning which I hope might useful if you're having the same problems.

 

During a 6 hour drive to Cumbria on the hottest day of the year (natch) it stopped working.

 

The temp of the air varied and then the water temp guage would climb way high. Turn the aircon off and slowly the guage would go back to normal.

 

When I got back home, I had it regassed by Mark IV Aircon in Langley. They used a new gas (R134a) and a new type of oil. It cost £78.38. I had rung several people and been told that I needed to replace seals and use a blend gas and (lots of other stories). Quotes varied up to £120 or more.

 

I asked the guys at Mark IV if this was necessary and they said no - it was just people trying to get more of my money. R134a and this new oil was all that was necessary.

 

(BTW, R134a runs different pressures to the old gas so the pressures in the manual no longer apply.)

 

(Note: a bit of searching found that Nissan has released a Technical Bulletin about retrofitting R134a and seals and stuff but I am too tight to spend the $25 to read it.)

 

A few days later, it misbehaved again (same symptoms) and eventually stopped completely. Back to Mark IV who discovered the pressure relief valve had blown.

 

This is in the pic on p HA39 of the manual.

 

This part does NOT exist as a separate part from Nissan - it's only available if you buy the entire pipe from the compressor to the condenser. Over £130 + VAT from Japan (and 6 weeks). And it's a b*gger to fit.

 

Luckily, MJP found me one on a breaking ZX. It simply unscrews and can be screwed on to the existing pipe.

 

Mark IV regassed again (this time including fluorescent dye which is a good idea whenever you get regassed as it helps detect leaks) and ran a pressure check. The pressure was still climbing too high so they recommended to clear out all the crud which accumulates on the condenser and the radiator (14 years of road dirt just sticks to the cooling fins and vastly reduces efficiency).

 

Also they discovered that the sub-fan relay (only on TTs not NA) was missing. So MJP again to the rescue with a s/h one.

 

(NA condenser fans are off/on, TTs are off/medium/high which is why they need a second relay).

 

Lucas Garage in Datchet semi-stripped condenser and radiator to give them a good blow through and got rid of lots of crud along with half a carrier bag which had got wedged in there. No wonder the cooling was not up to spec!

 

Last thing was a Consult check by Dan Perkins Nissan in Slough (thanks, James) which confirmed that everything was OK with the aircon- sensors, fans etc and the air temp was to spec as well (2.7°C).

 

So now, of course, the sun has gone in and the summer is over!

 

Cheers - Gio

I'd get a second opinion on the R134A.

 

The zed system runs at very high pressure - 300psi+. I think R134A would drive it even higher. Might explain the popped relief valve.

 

The guy who did mine said R416 or something like that was the compatible replacement for the original and used it in my mega mileage one. 2 years on and still chillin fine - no valves poppin.

 

He came out to my office to do it and charged £80.

 

Search on aircon in the forum it for more info / opinion.

Yes - the manual says that the relief valve pops at 540psi so things were getting a little too much!

 

The aircon guys also said that R134a would (as you say) run higher pressures than the old gas.

 

There are, apparently, several gas choices but most of these are blends which they now refuse to use. (For a reason I don't understand.)

 

In my visits to them I have seen several bourgemobiles but also a couple of Jags, a big Beemer, a Ferrari and a Triumph Stag so they appear to have a good rep.

 

But I'll have to wait until the next heatwave to tell you if they've done a perfect cure on mine!

 

Cheers - Gio

I came across this article a while back which included some info on Nissan A/C retrofits:

 

http://www.babcox.com/editorial/ic/ic59946.htm

 

-Andrew

Good post Gio - if only I'd known of those guys when I got my last car gassed (considering they're only 5 minutes from me), instead of using a mobile bloke who (IMHO) killed my compressor :'(

 

You live and learn!

when converting to R134a you only put 80% of the origional R12 gas in to maintain system pressure