DaveK

Well, this is interesting. I just spoke to two local air con places.

The first one (£85 + vat to leak check) said that sniffers are absolutely crap - that they have one and it stays in the bottom of the toolbox. Recharge with UV dye is the only way to go. They seemed very honest (at least on the phone) and said they had never done a 911.

The second one (£35 + vat to leak check) said that he does use a sniffer, but also uses the dye if he can't find the leak any other way. He has the advantage that he can come to me for the leak check - but he also told me he'd have to take the dash out to replace the evaporator. He is obviously a lot cheaper than the first place - but not sure which I'll choose for the leak test yet.

The one thing they both said though - is that you cannot use the sniffer in the air vents to detect a leak. You will always get a reading that way. Which is interesting - because that's how my mechanics came to the conclusion it's the evaporator (after not getting a reading anywhere else).

In the interests of economy (and convenience) I guess I should choose the second guy for the leak check. But from speaking to them on the phone - I actually think I may go with the first place.

Kahdmus

Regardless, this was the design criteria given to the designers at the very beginning of development.

You wanted a car that had all the problems ironesd out so you could do a full rebuild? Of the engine or the car?

springer3

They should, but probably don't know that freon is much heavier than air. Leaks drop straight down if the breeze is still enough. The best way to check the evaporator is to close the car up for a while, and then sniff in the footwells near the lower vents. Pushing the sniffer into the dash vents will not work, unless the leak is quite bad.

I have used a sniffer, and they work quite well if you can get close to the leak. I have equal success with soapy water. Wait about 10 minutes, and even a very small leak will start to create foam at the leak location. The dye works only where you can see it, and that is fewer places than the sniffer.

One place you can't get to with dye, soap, or a sniffer is the compressor shaft. It is behind the pulley/clutch, which looks to be a chore to remove on a 964. A sniffer directly below the shaft in a closed garage is what detected my compressor seal leak. That was on a Mercedes, but the compressor design is quite similar.

I'm surprised you even have AC shops in the UK. In Southeast USA, there is one on every corner, and they seem to do quite well this time of year.

ian c - u.k

a westfalia is a camper based on a vw type 2
a db6 shooting brake is an estate based on a db6

a boxster is a car designed with a 550 in mind (amongst other things)

i'm sure the designers of the 997 were thinking of earlier 911's when the designed the front end ....... perhaps they were ordered to
but , yet they say its 80% new ??
so , is it based on a carrera 3.2 ??



i think paul was talking about the problems early 964's had . it's reputation is based on these i think !!
i have a problem keeping money in my pocket . if the car was to break down , odds on i wouldn't have the funds available right there and then to fix it !!

my plan was to rebuild the car as a "rolling restoration" , hence i bought a car with the later cylinder head sealing , flywheel etc.
but.............. it turned into another of my "little" projects .
its now in the bodyshop for its second respray !!

as i was allways planning a full re-build , the fact that it is a 93 model is irrelevant , i agree . i can easily fit say , the dizzy vent kit and other improvements if i was restoring an earlier 964.

ian c - u.k

i probobly will buy a newer car , when my 964 wears out ...................


in 2025 !!!

Randall G.

Wow, that's amazing, and completely nonintuitive to me. But, it was two shops telling you the same thing. If every evaporator (even a brand new car, I presume) leaks enough to set off a sniffer at the vents, I would think the charge wouldn't last past a year. Are the sniffers that sensitive? If a good evaporator passes enough gas to set off the sniffer, I should think every threaded connection or seal would cause an alarm, too.

I will say I have no experience with using one of these sniffers. Though, I did watch the HVAC guy find a leak in the accumulator on my house's heat-pump system. Then, use it to verify no leaks, after welding in a new accumulator.

Like Springer, I think an awful lot of evaporators get replaced in error. Even just on Rennlist, I've lost track of how many "they told me it was in the evaporator, but the leak turned out to be elsewhere" stories I've read. Which isn't to say they never fail (as Springer has also suggested).

Dave....I've suppose you've figured out by now that the shop that told you the whole dash has to be removed to replace the evaporator was correct. I think evaporator failure is about the second worse thing that can happen to your 964, behind a major engine failure.

How long has the charge been lasting in your car, Dave?

DaveK

Er - haven't figured that out. I thought the evaporator was under the fuel tank (which definitely isn't behind the dash)?

Leak seemed to be fairly sudden - and last (partial) charge only lasted a few days.

Randall G.

Hey Dave,

Fuel tank has to come out, as does a good portion of the dash. Here's an excerpt from the shop manual, for a 993. Similar words in the 964 shop manual:

http://members.rennlist.com/rgranaas...stallation.jpg

Earlier, the CCU & radio are removed. The 993 instructions also specify removing the glove compartment. There are a few differences between the 964 & 993 set-ups (e.g., use of vacuum control for recirculation, mixing chamber servos are inside the cabin), so perhaps glove compartment removal isn't required on a 964? I don't know enough about the physical arrangement to say yes or no.

Here are the sections for removing the 964 HVAC unit:

http://members.rennlist.com/rgranaas...al%20964_1.jpg

http://members.rennlist.com/rgranaas...al%20964_2.jpg

Good luck! Hope your leak winds up being elsewhere.

Roygarth

Dave, I just used www.airconone.co.uk (brilliant name!) to service/vacuum/recharge for £70 inc. VAT including coming to my office to do it!

I can't vouch for his ability to deal with your sort of problem. All I know is that mine didn't work and now it does!