how to ID a zn4 ac compressor that will fit/work on a 1998 ?

[vernon]

How in the world do you identify ac compressor for a 1998 Blazer with zn4 option?? I tried a salvage yard unit but it was the wrong one. What numbers and ID should be on the correct one for my 1998 Blazer w/opt ZN4( since the original factory unit was thrown away a long time ago)?????

[ex IROC Crew]

What is a ZN4 option? I have a booklet published by GM Service Parts Operations called "GM Production Options, Passenger Car, Light and Medium Truck," and no ZN4 option is shown---for any vehicle. The booklet is effective May, 1999 and shows options back in the '70s, so it should be covered. As far as I know, there was only one compressor available for any Blazer that year. As far as updating and backdating, check a few different models on Rockauto.com.

[4x4x4doors]

The only reference to ZN4 I can find identifies it as extended production which implies that there was a mid-year change. GM has been known to make some changes to next model year parts mid-cycle. What this may mean to you is that you are looking for the same compressor as was used on the 99. (I am not aware of any differences in the 98 and 99 compressor but that doesn't mean they weren't somehow different.)

[vernon]

I understand that the zn4 option referred to "an extended production run". I still need to know the actual difference in appearance, numbers, ID, etc. between the zn4/ext run compressor and any others that were used on the non-climate controlled automatic air version.
My 1998 Blazer has the factory automatic climate controlled ac, which is referred to as ZN4, extended production unit.
Thanks- please help.

[4x4x4doors]

I don't know if this will help at all or not. It's the picture of the manual a/c compressor from a 99 Factory Service Manual. I don't have any part numbers and I know sometimes they still use "representative drawings". Maybe it will be different than the one you already tried and will help.

Also, suggest you check Autozone, NAPA or even the Chevy dealer for part numbers. Seems last time I bought a rebuilt at Autozone it was around $190 but its been several years. If you get one from one of them, you can take it back if its the wrong one AND you've got a better chance of the seals not being worn to the point of being useless anyway.

Good luck and keep us posted what you find out.