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Chevy S10 ZN4

Looking for a starter for my 1998 S10 and it asks with ZN4 or without. What is ZN4?

It is a 2.2L, RWD, 4 cyl pickup.

ZN4 is an option code, although I don’t know what it means. Look for your option list tag. This is normally a sticker found inside the glove box, often adhered to the inside of the glove box door. You will see a list of three digit codes like the ZN4 you mentioned. If ZN4 is not on the list, your truck doesn’t have it.

Thanks! That solves my problem.

Here’s a description of RPO codes from an S10 forum, as Mark stated the RPO (aka SPID) codes are on a sticker in the glove box. Ask a dealer nicely and they can print out a list of option on the truck based on the VIN number.

"Product Availability

Due to marketing concerns, some models may have VIN badges to indicate one model year, but the engine content may actually be of a previous, or of a future year. This can cause confusion when trying to reference a Model Year (MY) for service concerns. To address this, two RPOs have been designated to indicate a MY “pull ahead” or “Push back”. These RPOs (and an explanation) are as follows.

  1. RPO “ZN4”

Which means a vehicle is badged for one model year while it is being manufactured into the next (pushed back). A specific case of this are some 1998 S/T pickup trucks which are VIN’d as 1998, but are manufactured after the traditional August changeover, and contain 1999 Powertrain components. These trucks would contain RPO “+ZN4”. "

Ed B.

Sounds like an alternative to the old question of “built before or after --/–?” The option code method probably also allows GM to use up more of the old parts.