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Jag Tensioner Quest - Finally some information and progress!

Holy crap the puzzle pieces are actually starting to fall into place! I’d be excited if I weren’t so irritated it has taken this long.

A brief catch up: I found out my supercharger belt idler pulley and tensioner both had marginal bearings. While I had everything off and accessible I figured I would replace them,but finding the parts proved difficult and when I did find them, they were very expensive. There were whispers and mummers of a “update” kit that was required, at the cost of between $300 and $400. I’d also found a generic tensioner pulley that was dimensionally almost perfect and make some inroads on sourcing new bearings too.

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Starting Wednesday things started to look up. I’d found one of the generic replacement pulleys at a local O’Reillys for $35. I figured I could buy it, check to see if it was a match, and return it if not. On a whim I was at a local mechanic friend’s shop picking up some tools they’d borrowed from me (weird, right? The Saab saga has left me with a lot of specialized stuff...) when they offered to try and find the replacement parts for me..

Neat!

They also had no luck.

Ha! But hey about about that generic replacement?

It can be here in an hour for $12.

Cool. While we’re at it lets get some DOT4?

How about Type 200 for $1 more?

Three liters please!

$50 later I left a happy man. I suspect my cars (Alfa, Disco, and Jag all need brake fluid flushes) will also be happy with my choices.

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So, the million dollar one-hundred and thirty-eight dollar question: Is the pulley the same?

Yes? Mostly.

Dimensionally I’d call it nearly identical, with less than a 0.5mm variance here and there. Offset also seems to be spot on, with the replacement having a 1.5mm smaller backspacing BUT, that is from the pulley collar, not the bearing surface. From the bearing surface it appears to be identical and I think that is where contact with the vehicle is made. (wouldn’t really made sense otherwise...

Illustration for article titled Jag Tensioner Quest - Finally some information and progress!
Illustration for article titled Jag Tensioner Quest - Finally some information and progress!
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Illustration for article titled Jag Tensioner Quest - Finally some information and progress!

The bearing itself is smaller on the replacement, being a 6203 vs a 6303 (guessed) on the old one.  Not sure I care?

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So... calling that one a success and planning on sending the $150 one back when it arrives.

But the tensioner still remains. However, there is progress. I’d mentioned last post that I emailed a parts supplier I really liked, JLR Classic Works, (I figure they deserve a plug at this point) and asked them for more info. They responded with this:

I don’t have access to TSBs myself but my understanding is that plastic pulleys were replaced with metal ones, which require a different belt and tensioner bracket. This change also took place on X308 and XK8.

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My Jag already has metal pulley’s.

My Jag (likely) has already been updated.

Also probably means the supercharger belt I bought was the wrong one. Good thing I kept the old one for compariso- shit....

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:facepalm:

Well alright. On the bright side that means have guaranteed sources for the tensioner, all at around $120. Also this means that the tensioner that is in there has even fewer miles on it than previously thought, removing any lingering doubt about just replacing the pulley.

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Also it affirms my suspicion that this car was taken care of at some point in its life. Unfortunately I also have a lot of evidence to suggest the last owner (dealer) abused the shit out of it....

Armed with new knowledge, I set out to remove the tensioner. This was not an easy job as it requires removing an oil cooler pipe to make enough access to get at the bolt.

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Allegedly.

I removed the oil cooler, which, of course, promptly dumped a quart of oil onto my driveway, but then looking at it I’m not sure how this helped me. The issue isn’t (really) space to the left and right of the bolt, but up and down. The tensioner has different cooler pipes above and below it which limit access. You can readily see the bolt head from underneath, but access with a wrench is limited by the front subframe (or just... frame... whichever).

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Since the floor was now covered in oil and I didn’t really feel like wallowing in it, I opted to remove the supercharger water pump as I knew it would dump at least a little coolant on the floor. If I was going to have to wait for kitty litter to do its thing, I might as well go whole hog.

It made a mess. So much more coolant came out than expected.

Oil. Coolant. Oil mixed with coolant. On the ground. On the car. On my tools.

Everywhere.

Illustration for article titled Jag Tensioner Quest - Finally some information and progress!
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But this gave me reason to clean and organize my tools as I now needed to clean the area so it can dry/kitty litter overnight. So I cleaned my tools and plotted my next move.

Oh and I replaced the coolant temperature sensor. Still can’t find the cylinder head temperature sensor though....

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Illustration for article titled Jag Tensioner Quest - Finally some information and progress!

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