If you're purchasing re-manufactured injectors for your port injected 4.2, examine the o-rings on them for quality and correct application. The block side rings are usually viton because of the heat of the block. Also, viton is highly resistant to petroleum products.

However, the reman house may try to skimp on the fuel rail orings because there's little heat on the rail. But these rings may be affected by the fuel. I don't know what material the black o-rings on my purchased injectors were made from -- but it's a fair assumption it wasn't viton.

I purchased six reman'd injectors, with black orings, and installed them. After 25 months the fuel rail o-rings began to leak -- a lot. As in dripping off the engine onto the floor when the rail was pressurized. Good news, never found an ignition source. Had a bit of a "holy ****" moment when I saw fuel blowing out of the rail....

Below are three orings from my car. The black ones were installed on the injector by the reman house, and are hard and shrunken after 25 months. The blue viton (on two previously installed units) after 40 months are still flexible and correctly sized, though slightly discolored. A new viton oring is included for comparison.

So, wherever you get your new (or re-manufactured) injectors, examine the fuel rail o-ring. If you're not sure of the material, replace it with one that will retain it's size and sealing before you install it, and does not react with hydrocarbons (fuel).

And if you smell fuel when the outside air vent is open, stop and figure it out. The XK vent gets its air from under the hood/bonnet. The only places a fuel smell can come from under the hood/bonnet are the fuel lines/rails/injectors assemblies. Don't ignore it.

Hope this helps if you're DIY. EDIT: actual measurements with a digital caliper of the blue and green oring are a few posts below.

(NOTE: there's a likely but not intrinsic color scheme for o-rings. For example, blue or green is likely viton, but could be other less effective materials as well. Black can also be viton. Here's an explanation of the relationships: https://www.callapg.com/blog-oring-colors .)


Panthera

 

yeah… I have learned to avoid most aftermarket or non-oem supplied solutions due to situations like these.

 

Good info. Thank you!
What size are the replacement o-rings?

 

These are my actual caliper measurements of the blue viton o-rings above:

OD of oring 14.64 mm
ID of oring 7.67 mm
Diameter of ring material: 3.52 mm

The inlet pipe on the injector measures 8mm exactly, so the 7.67 will be tight on the injector pipe. I do not have a direct measurement for the fuel rail orifice, but the old black hardened oring has an OD of 13 mm, so I'm thinking that's the ID of the fuel rail orifice.

And since I had the calipers out, the green viton oring is as follows:

OD: 14.86 mm
ID: 9.26
Ring: 2.83 mm

Note these are actual measurements with a digital caliper, not whatever a catalog would say. This should get you close enough to match.

 

Thank you👍