OK, may seem like a stupid question but let me explain. Recently a friend of my Fathers gave me his '95 GC lmtd for free. The jeep has a 4.0 in it and shows 150k miles. When I went to change the oil, the oil filter the book called for STP S16 was the wrong shape/size and did not fit. Using the number off the old filter V195, one of those jiffy lube type filters, the counter person at autozone was able to cross reference the correct filter for me. So Im thinking maybe the motor was changed at some point? Also on the block is some painted white letters making me think its a motor out of the jy. I want to change the plugs hence my question about which plugs. Is there a way to determine what year motor this is? Serial number somewhere? Or should I just buy whatever is in there now? And my Dads friend says he didnt change the motor but he bought it with 107k on it so who knows what happened before he owned it. Any thoughts appreciated.
Thanks, Cory

 

Sounds like you have a RENIX vs HO scenario. Between the two they take different oil filters and spark plugs, sounds like you have a RENIX block or engine. RENIX was 87-91, HO 92-up. The difference in plugs is just a couple heat ranges, nothing else. The RENIX ran a slightly colder plug than the HO. Its a guess right now what plugs are in it but you will be safe running whatever, I would probably just have them cross whatever is in there or you could use vehicle specific info for plugs.

 

Thanks for the reply. That makes sense as the oil filter was a closer match to my '89 wagoneer lmtd with the 4.0. So if its renix I'll probably just go with what my 89 called for. Again, thx for the help. Still learning about Jeeps, after almost 40 years of driving and never owning one I now own 3, go figure.

 

Same here! After 50 years of driving, I've owned 5 4X4s and the last 2 were Jeeps, one that I'm still driving. I don't know what I'll buy next because of all the useless electronics in today's cars, but I'll bet it will be a Jeep of some sort.

I'm not a fan of electronic traction control, ABS, automatic braking, collision avoidance, or any other suppliments to my own ability, and I still like a manually shifted transfer case. Call me an old fart if you will, but I still like to make my own decisions and not have my car driving ME!

 

Believe it or not we got our 1st one last summer because my wife liked it. After my son totaled my Trailblazer we were looking for something similiar so she found a '10 GC Laredo she liked, who was I to argue? Then last year a friend offered me his 1 owner 89 wagoneer lmtd that needed a little work for 350 bux, how could I refuse that.? Now this 95 GC lmtd for free, keeps on getting better. If the 95 works out the 89 will go on the block unless my son wants to total that also.
As for the plug issue, the book calls for Champion RC9YC and since a little colder plug was recommended Im guessing RC8YC??

 

as an update I went to autozone to pick up plugs and went with renix era champion rc9yc. When I pulled the plugs they were rc12lyc which I believe is what the HO motor called for. We'll see how it runs, have a memorial day weekend trips coming up. Thx for all the help, Cory

 

did the plugs end up working or what happened to that?

 

You got caught in an 8 year old thread. I doubt if anybody is listening.