Restoring an old classic jag with no ac.
Put manifold gauges on it, zero!. So much for POs “just needs topping up”.
Connected a vaccum pump, wont hold vacuum for more than 30 secs… so my usual approach of using a electronic sniffer is not gonna fly. Can not see or hear any visible leaks, looked at all hoses and joints.
Any suggestions for conclusively tracking the leak using equipment we have at dms, instead of throwing parts at it?
Try “charging” with another medium. Popular choices include compressed air, helium, co2, whatever is on hand for weld shielding. Sticking to non- explosive is best (no propane please). Should not run the compressor on any of that though. If all that fails, ya gotta spend $$ and do a charge with dye. From your description so far though I’d bet you’ll hear it if you just hit it with shop air. …
Sunny,
1st Method
First, if you suspect an ultraviolet dye has ever been used (like is often mixed with the refrigerant oil) then look at it at night with an ultraviolet flashlight and see if there is an obvious glow on one of the A/C lines or components. That is probably your leak point. (assuming there is only one - could be more) You may be able to see an oily, dirty spot on the lines / fittings just by doing a visual recon as refrigerant oil typically leaks out with the freon.
2nd Method
Pull it down to vacuum, stop, and then during that 30 second window or more, use an electronic ultrasonic listening device (find them on Amazon under Automotive) to locate the leak. (there are less expensive models listed on the Amazon page itself)
3rd Method
Replace all easily accessible O-Rings in the system and then see if it will hold a charge.
JAG “Name Is A Coincidence - I Am Not a Fan of Jaguar” MAN
That’s a sad coincidence. Jag motor cars freakin’ rock! To look at…
Not a fan of fixing them myself, but I love steeping in their mythology…
Ja “I pronounce it jagwar, she says jagyoouh” st
PS in further news me name doesn’t lend itself to that “middle name pithy maxim” thing…
Andrew,
That’s a sad coincidence.
It’s an annoying irony as people keep automatically assuming I love Jaguar. Okay, I do like felines of just about any description, and the idea of a cat that could shred an intruder is pretty funny to me.
PS in further news me name doesn’t lend itself to that “middle name pithy maxim” thing…
That makes me sadder. (but flattered, nonetheless)
But is it really too late? You can always add a suffix to your handle, can’t you?
That’s a sad coincidence. Jag motor cars freakin’ rock!
I love the U.K., but despise nearly all British cars (at least the ones that make it over here) and to quote Dave Barry the Pulitzer Prize winning humor writer:
" In recent years, it has become fashionable to give children extremely British-sounding names, such as ‘Jessica.’ I think this is an excellent idea. Despite the fact that Great Britain has been unable to produce a car that can be driven all the way across a shopping mall parking lot without major engine failure, Americans think that anything British is really terrific."
However I will admit that I enjoy driving in Britain a lot - particularly from the passenger seat and manual shifting with my left hand on the wrong side of the road. It’s a mild learning curve, but wonderful for neuroplasticity.
At any rate, to each his own; if other people like Jags, who am I to say they shouldn’t? Look up the Vulcan IDIC for further explanation.
JAG “Roundabout Down To The Wickershams at Warp 6” MAN
Maybe pressurize with compressed air, pour soapy water on the plumbing and look for bubbles?
Throw a can of freon in it, turn on the blower and stick your electronic sniffer in the vents inside…most likely that is where the leak is if you can’t see oily residue under the hood.
What year and model is your classic Jag? To be true classic Jag it has to be a positive earth model (goes for most classic British cars)…
That information would be very helpful!
Evaporator leaks will never show up with a dye test or under hood visual test. What if any work have you already done to the AC system? This too may help in resolving your issue.
If you cannot pull ANY vacume with a real vacume pump than you have a fairly good sized leak.
That’s a big no-no. Then, legally speaking, you’ll have to pay someone to take that Freon out with a recovery machine before fixing the leak.
I’d use cheap N2 or Argon, then soapy water in a spray bottle. In a pinch, shop air.
Shop air can have a lot of moisture in it. I would think a dry gas
would be much better.
Ed
Largely irrelevant, especially if you’re fixing it immediately. You’ll suck all the moisture out during draw down, but even if you don’t, the atmosphere currently occupying that space is sure to be just as moist…
Thanks for the pointers guys. Filling up with shop air seems logical to me as well, don’t want to wantonly release R134a into the atmosphere, so dyes and sniffer are out. Btw, my sniffer is a sub $50 unit, had good reviews on Amazon under no moisture conditions. Will put some new Schrader valve cores and pump it up gradually and check with soap water if i don’t hear any hissing. I assume there is an adjustable regulator on the shop line
With a leak this big, theres already air in the system so replacing the dryer is something I’ll have to do anyway.
@tom, its a 80s Series3 V12, not quite an e type or xk120. Imported it from Canada, the US had the XJ6, but not the 12 on the S3.
Sunny,
A mechanics stethoscope (take off the vibration diaphragm) might point you in the right direction without the expense of an ultrasonic. Tom is correct about a leak that big generally being obvious unless it is in the evaporator core area.
Also, I believe you can do a straight refrigerant oil charge with leak detector WITHOUT blowing R-134a into the wind. Still would check with UV light at night first - might be very obvious if dye is in system already.
Agreed on replacing the dryer with any A/C system repair.
Oh, and I would apply the bubble solution on first and then inject whatever gaseous medium so that the bubbles are obviously from the leak.
You’ll suck all the moisture out during draw down, but even if you don’t, the atmosphere currently occupying that space is sure to be just as moist…
However, I do not agree that shop air is at the same humidity as atmosphere (remember that it compresses the water vapor as well as the air) and in theory it can inject enough water into the system that pumpdown could take a lot longer than if you use an inline dryer with the shop air.
JAG “Stay Cool” MAN
but then is put through a “drying rigor” to remove “all” the moisture, since none of the tools on shop air like to work long-term with water in the air.
In theory, shop air is MUCH dryer than atmosphere, since it is intentionally dried post-compression.
Giving a little to each side of the argument for lack of perfection in any system, I still argue for a draw on “injecting moisture” by using shop air.
But ultimately Sunny has to make that choice.
I can give anecdotal evidence that the shop air system will work fine, and @sunnyt you can just put a blower on and give it alls she’s got. Shop air (generally, I’m not familiar with DMS’s) runs <200PSI, and automotive R12 systems run ~150-300PSI when fully charged, with 400PSI being the “oh shit” level for blowing components. Point being, if it blows at shop air pressure of <200PSI, it was going to blow anyway during use.
Good luck with it!
Keep us posted!
Love the V12!!! (just don’t lose anything into that engine bay, cause you’ll never find it! 
Andrew,
but then is put through a “drying rigor” to remove “all” the moisture, since none of the tools on shop air like to work long-term with water in the air. I can give anecdotal evidence that the shop air system will work fine,
If it’s the compressed air at DMS, that may be true, but I have a compressor at home and it will blow condensed water through the lines unless I install an inline dryer.
In theory, shop air is MUCH dryer than atmosphere, since it is intentionally dried post-compression.
You mean in theory the shop air at DMS which has a water trap and I believe a refrigerated air dryer, but NOT in general. Otherwise compressors do not always automatically come with desiccant fairies.
That is why they sell these at every major hardware store…
http://www.northerntool.com/shop/tools/product_200319833_200319833
I am not assuming that Sunny is going to do ALL of the work on his Jaguar at DMS (but perhaps he is) and I just wanted to warn him about blowing unnecessary amounts of water into the lines.
If you were operating on the premise that he is, then it will probably be fine and you are certainly correct that Sunny has to make the choice. I think our debate was accidentally about the specifics of DMS air, not compressed air in general which is what I cautioning about.
You have useful information, Andrew; I just don’t want to see a pumpdown take longer than it has to.
JAG “Silica Bags - Eat With Milk and Maple Syrup” MAN
True. Compressed != shop until it’s treated, specifically with moisture removed. I learned this in my machine shop job. Oil conditioning is less “standard”, but pretty well across the board, if a shop of any kind has air for professional use, it’s at least got the moisture removed; if they don’t, it’s not shop air, it’s compressed air. Home users, and hobbyists, of course, mileage may vary.
A fair point, and assuming vernacular matches, i.e. per my above compressed != shop .
Another fair point; I had assumed we were using DMS resources exclusively.
And I appreciate your input as well. It helps me pump the brakes from time to time, and hopefully we all (especially Sunny) benefit.
Sunny,
I’ve worked on many V12 jags in my younger days. The older Jags are nice - the V12 can be tough to work but the 80’s V12 in the old 750/850 beamers were worse.
Good to know that DMS has a dryer on the shop air. I think I also recall something about some air lines having an oiler (or I may be mixing up another location) which I certainly would not want to use for this project. So the flex line that I see lying around the auto area is the one I want, correct?
@tom, tentatively planning on Wednesday evening, around 7 or so.