I bought my 2001 Z06 back in 2014, and have put a little over 2000 miles on it. I just did the first tuneup. It has nearly 70K, and I pulled out Densos, so it's had at least one tuneup by the previous owner, who seemed to be on top of things. I used to work as a pro for about 20 years, and from looking at the plugs I'd guess they had less than 30K. The #2 from the front on the driver's side plug, (number 3 cylinder if the same specs as older 5.7L engines had,) had a burned down electrode. This burned away electrode was down to the porcelain. None of the other plugs showed this abnormality. I do remember that vacuum leaks can cause unusually high cylinder temps, but I don't hear any hissing, and listening to the exhaust at idle, it sounds very normal. Any guesses on this for this particular engine? The other question I have is that I have a freon leak. It's pretty big, because I can't even bring it up to working for any length of time, from manual loading via small cans of R134. The main reason I'm bringing this up, is because I talked to a local Corvette "expert," and he was sure, without any diagnosis that it was a compressor leak, which would need to be changed out, to the tune of $1400. To me, the guy wasn't that knowledgeable after talking about several subjects, and trying to sign someone up for a big job like that, without a diagnosis seems unprofessional. If this compressor does have the leak he's talking about, I would assume I could load some dye in the system, and laying under the car and looking up with a UV light, I should be able to see a leak. Any thoughts or opinions on this? Thanks.

 

Unless he is Kreskin or a fortune teller how the heck can you diagnose sn ac leak without diagnosing it? It might be a compressor - not uncommon - but why not just diagnose it properly? Use dye but not sealer!

On the plugs you're probably going to have to wait and see but you could ask a guy like C5Diag - maybe he has some scan parameters for you to look at.

 

Hi !!...my ears were burning...LOL !!...if it’s just #3 it wouldn’t be a vacuum leak such as a leaky intake bellows which would affect all cylinders...I would look for a leaky intake runner on #3 cylinder or a bad injector...if a pro I’m assuming you have a scan tool...what do your bank 1 fuel trims look like ??...any misfire counters on #3 ??...also the AC Delco 41-162 plug I believe replaces the old 41-110 !!...as far as the leak I just use a “sniffer” but it can be leaking from a few different areas !!

 

When the compressor leaks badly, it leaks both refridgerent and oil, with the oil leaving a pretty visible residue. If you have much in the way of an oil stain on or around the center of the compressor or its environs, then you probably do have a compressor leak -- and they are pretty common on this compressor. The $1400 is hard to evaluate without the full details -- obviously he's talking of replacing the compressor, but is he replacing the condenser or just flushing? Replacement is the recommended action, as there are very small passages that apparantly don't flush well. Which replacement compressor? GM, Delphi, Napa, Autozone? Different levels of quality, cost and warranty. Lots of 1 year warranties for installation that's significantly more money than the part.

 

I had to re torque the intake on my car many times two alleviate vacuum leaks. I would say it took five or six times over a period of 2 years to get that perfect. The ABS plastic gives a little bit overtime and for whatever reason I had to keep on top of it.

I would expect though that if you had one intake runner leaking, they would all leak. Or most of them. A better explanation would be it is running lean because you have an injector that's plugged.

 

I was about to change spark plugs on my 2000 c5 with 32k original Mi. AC delco 41-410 Iridium replacements. They came gapped at ,04. Manual says gap .06 Should I leave them at .04? or regap to .06?
Maybe iridium has different gap from what could be the original copper ones? Also I find varying torque recommendations. 15lbs?
Thanks!