Camshaft Chain Tensioner Plug

1990 XJ-S and 1991 XJ-S Classic Collection Coupes (US Spec, 5.3L V12)



Tensioner Plug

Knife, Screwdriver, and/or Poker

3/32” Allen (Hex) Wrench


The Camshaft Chain Tensioner Plug is in the front of the engine, a little up and left of center (when looking at the engine from the front).  I don’t think they had ever been changed on either one of my XJ-S Coupes.  The original plug is a rubber material that is very likely to leak.  This is a quick, stand-alone job (nothing else needs to be removed).


As per nearly everybody, I got a replacement Plug from Ron Kelnhofer for $18.75 (e-mail Ron for more information, you can pay him using Paypal).  He is responsive and was very helpful when I wanted to talk with him on the phone.  There is a picture of the plug at Garage Engineering, but they do not sell it directly.


The toughest part of this job is to get as much of the old plug out as possible, dropping as little rubber into the engine as you can.  Bernard Embden has an excellent web page explaining the Tensioner Plug replacement and he indicates losing a little of the old plug shouldn’t harm anything (it didn’t seem to be any problem for either of my cars).  First, try to clean up as much as possible around the hole – you can see how ugly it was around the plug on my ’91 Coupe before I started this job.  Then use a poker or screwdriver and/or knife to get the old plug out.


Old Camshaft Chain Tensioner Plug – 1991 XJ-S Coupe

(Viewed from Front, Camera at Main Fan)




   New Ron Kelnhofer Tensioner Plug


Loosen the setscrew from the new Tensioner Plug using a 3/32” Allen Wrench.  Put the new plug in the hole, with the beveled side down – a little wiggling is required, but it will get in there.  Tighten the setscrew.  Ron K. was cleaver enough to add a second hole if you ever need to remove the plug, just loosen the setscrew, insert a 1/4”-20 bolt into the upper hole, and pull it out.


New Tensioner Plug Installed – 1990 XJ-S

(Viewed from Front, Camera at Main Fan)




Questions/comments: Email me.