First time poster here.

How can you tell if a 1999 model year is a 1999.5 with the updated exhaust/heads? I'm looking to buy a '97-98, but I'd consider a '99 if I knew I wouldn't have to deal with the 0331 head issue.

Thanks.

 

The 0331 head only came on the 2000-2001 XJs. The dead giveaway is the coil pack and no distributor. A 1999.5 would be sold as a 2000 model anyway. My WJ was built in August of 1999 and was sold as a 2000. My 2000 XJ was built in February of 2000. Look at the sticker on the driver's door jamb for the build date.

 

Excellent, thanks. I guess it was just me misreading some of the year explanations/terminology on other threads.

 

I think it was 97? Anyhow they changed the intake manifold design for better airflow and that's what people are generally talking about. People also get confused about what the HO means. I'm not sure myself, but I think anything after the Renix is an HO or High Output.

With the newer block change for the WJ model, they also changed the cam profile so the 4.0 makes max torque at 4000 rpm instead of 3000 rpm. This was to make them a better high speed road car than anything else. The 0331 head has tiny exhaust ports to help maintain emission standards.

 

The better intake wasn't until the 2000 model or maybe 99. The 97 and 98s still used the older style.

 

Oh, okay! So that's where the problem lies with swapping for the newer one. The accessory mounting holes for the newer type are in the manifold and not in brackets like the older models. I know on my WJ the A/C compressor mounts under the PS pump and the alternator is high on the passenger's side where the compressor used to be.

 

That's the difference between an XJ and WJ. A intake manifold out of a 2000 XJ was pretty much a direct swap in my 97 XJ no mounting points changed.

 

Ya see? I'm still learning. I'm new to the XJ game but have 8 years with my WJ. Same engine....sort of! The main thing I've found is the fan is not mounted directly on the water pump as it is in the WJ when it has a clutchfan, but offset, but it is on XJs without A/C. And they don't have electric aux fans. I've never seen an XJ without A/C.

 

delete msg, scrolled too quickly on a very long FS thread with pictures and was presented with this old thread.