Not that I haven't been told by all of you to check this two years ago when I bought this vehicle - well, I finally have the cam covers off and will be replacing ONE (99 Jaguar XJ8 Driver's Side Timing Chain Tensioner - upper) and the old plastic thermostat housing.

Short background. Purchased car in November of 2010 with 93711 miles on it for $7188. (including financing). Returned the car three weeks later (with all your directed input that sound was a tensioner - and it was!). I practically begged the dealer to change both tensioners, as recommended, but even with me saying that I would pay the extra, he declined. I still always had a slight "dieseling" sound (very light constant tapping from the middle rear of the engine).

A week and a half ago, I had drove a 100 miles away from home and received a restricted performance light, so I stopped and checked oil and water - they were fine. Not the brightest thing to do but I hard reset the system and began driving home, CEL came on. Temperature gauge started climbing, I stopped and looked under the hood - upper radiator hose was coming off the nipple of the housing (plastic housing). I tightened it down, checked water - ok.

When I got home I used my $15 cheapo OBDII to check codes - didn't write them down - and reset the CEL. Decided to take radiator hose off and look at housing/thermostat,etc.

Here's what my 1999 original plastic thermostat COVER looked like after removal:
OUTSIDE (below)


INSIDE (below)


The above photos are interesting, just like it was interesting that the nipple end (shown as the chipped or broken part) simply disintegrated when I squeezed that end - so it was definitely ready for replacement. The rest of the housing appeared to be in working condition - but complete replacement was my decision.

No big deal I suppose - I check Jaguar Forum (as always), and decided to change the entire unit to the metal upgrade, which I ordered from anhautoparts on Ebay for $52.20 (free shipping):

HERE'S WHAT I ORDERED:


I also purchased a new THERMOSTAT from anhautoparts on Ebay for $36.00 (free shipping).

What I've learned so far (mechanically) during the removal of the Thermostat Housing:

The rear bolts of the Thermostat Housing are difficult to remove, however, this forum has many great ideas (from great minds and a lot of experience - use them!). As of this moment, I haven't decided on how to do this - If I use an open-ended crow's foot, then I might risk stripping the bolt and them I'm screwed. You can buy the 8mm crows foot from Snap-On HERE for $17.35 (plus shipping). I already tried to bend a craftsman 8mm wrench and it snapped in half - I don't have a torch to heat it, so I'm still thinking about that while I wait on the Thermostat housing to arrive anyway. I believe that using an 8mm crows foot SPANNER would be proper. see Veteran Member Gus' site for more information and hints on the Thermostat Housing Replacement HERE.

ON TO VALVE COVER REMOVAL:

This process is what is getting me TOWARDS the replacement of the Driver's Side Timing Chaing Tensioner. The removal of the valve covers was pretty easy (with the right tools in hand and lots of forum reading).

Here's what I learned DURING THE PROCESS:

1. That in my situation, the oil dipstick was easily wiggled up (after removing the top nut) to allow me to unscrew that 10mm bolt from the valve cover. Most say that you should not wiggle and pull TOO MUCH as you'll remove the dipstick from its housing - I agree, so use a controlled "twist and pull" method. I also took pliers and bent the dipstick tab up a LITTLE just to clear the bolt.

2. I thought this was important for those of us who don't have a garage full of tools - when preparing to remove the valve covers - they are 10mm bolts, however, not all are flat - there are some that have extended bodies for the attachment of accessories - SO BUY THE $5.00 10mm DEEP SOCKET.

Here's what my cam shafts looked like after I "opened them up":

CAMSHAFT LEFT SIDE - (below)


CAMSHAFT RIGHT SIDE - (below) (notice the upgraded Chain Tensioner that was replaced by the dealer two weeks after I bought the car)


Okay, on first look - I'm not a mechanic - what's wrong with these photos? Why are the camshafts this color? Brown! Is that burnt oil?

Here's a photo of the OLD Driver's Side Chain Tensioner (IN PLACE) (below):



Here is a close-up of the LEFT SIDE (Driver's Side) Timing Chain Area (below):


Both LEFT and RIGHT side of the Timing Chain Areas look alike - it almost seems to me that the top portion is not even getting oil as that area is dry, no sheen of oil at all. Any input from anyone who has seen this before?

Here are the inside of the VALVE COVERS - Maybe some information can be gleaned from them?

Left (Driver's) Side (below):


Right (Passenger) Side (below):


Well, that's where I'm at on Sunday, 10 June 2012. Waiting on parts. I know I have to buy a gasket set for the valve covers - any suggestions for a reasonable priced set of good quality?

Any suggestions before I go further would be appreciated. I am concerned with that discoloration - should I be?

I don't want to change the water pump as it's not leaking and I'm frustrated about the "metal vs. plastic" impellers, then having to change, or not, to another type of anti-cavitating anti-freeze (where does it say that I the bottle - LOL). It seems like there are way too many variations of "advice" on that issue. I searched this forum for several hours and don't see anyone pointing to a new water pump with plastic impellers for sale. If you know of a dealer - please let me know and I'll consider it (price considerations of course).

Off to eat my daily meal and I'll follow this up either when I get input from anyone, or once I receive some of the ordered parts - again, suggestions and advice are welcome!

Vin Number: SAJKD604XXC866625
Eng Number: 981215 1511 / 22233322

 

I pieced together a set off of ebay. You need 1 grommet for each bolt, 4 pcs for the spark plug tubes, and one of each main vc gaskets. Those skinny black ones they sell for cheap arent going to work here. Excellent photos! Keep up the good work!

 

You have the AJ27 engine so a FelPro set of valve cover gaskets will be available at most any AP store. Ask for a '00 Lincoln LS. Under $40.

Be sure to put a small dollop of RTV on the pad at the engine/front case joints. 'Dollop' is an engineering term taught in most Southern schools.

The other solution to the rear bolt access is a ground down 1/4" drive 8mm socket.

I cut a screwdriver slot into two of the bolts to make running them down easier. Others have replaced with Allen socket bolts which is what should have been used to begin with.

Yes, your engine appears to have a less than perfect maintenance history. I am surprised that there is not more oil 'wetness' showing.

 

Those black skinny Lincoln LS gaskets arent going to work on those covers. The tube seals and stuff may fit, but the large gaskets that go around the perimeter are different. I ran into this problem when I did my tensioners. The guy couldnt believe my car had the orange and grey gaskets, but it did I started a thread about this last year or so.

Another thing to think about is changing the seal for the VCT solenoid. I wish I would have done that while I was in there.

 

I just recently finished the same evolution. I ordered the same aluminum housing kit and had a problem with the O-ring sealing in the cap. You can see it in the picture you posted. The surface it contacts was not machined and I had to do it by hand and then reused the existing cap because it had a nice flat full face rubber gasket.
I also found upon removal that the coolant pipe was broken and had to replace it. I had no luck with the back bolts so i went the pull the manifold route. Lots of room and a chance to seal everything up nice and dry. With the manifold off it was also much easier to replace the original equipment hose that runs under the manifold from the back ot the engine to the thermostat tower.
I tried the gasket route for the aftermarket and had to return them the gaskets just wouldn't fit right. I bought a new set from JAGBITS and yes they came as a grey and orange with the figure eight spark plug gaskets.
I spent a lot of extra time just so I could be sure of not going back in the engine any time in the near future.
Vernoon Robinson
1998 XJ8

 

I took the intake manifold off too. I had to replace my part load breather hose and replaced the two heater hoses that run under there. You can also clean the throttle body while you're at it. I also replaced the outlet pipe in the front that is plastic. Mine had begun to deform. I couldn't find one of these that was not plastic, but it should be good for a few years anyway. I used a 1/4 drive ratchet for everything. You don't want to get crazy with these parts. The rubber o-rings are nice.

 

IXJIT - Here's your post you were talking about. I was reading it last night (thanks). You and Test Point had that very same discussion at that time as well. I guess Avern1 (below) has found the set (and I confirmed with JagBits) - so that's the route I'm going.

Here a thread front BRUTAL and WhiteXKR on how to remove reinstall the 99 XJ8 VVT seals.

Test Point - I know - that discoloration concerns me, as I haven't seen an engine on this site (yet) looking like that under the valve covers - embarrassing at least - a future problem, I don't know yet. I like the idea of grinding the socket, I'll look into that too - especially since I just bought a new 8mm combo wrench and I was going to heat it and bend it (like GUS did), but the propane torch I bought from ACE hardware was leaking, so I brought it back. I would also like to search out some new bolt types for the back of the Thermostat Housing to make installation/repair easier. I'll post whatever I do wind up using. (Thank you) BTW: Which is more, a "dollop" or a "plop"?

Avern1 - I Just called JagBits about that part. I was asked for the last 6 of my VIN and was told "oh, that's an earlier model", and that the correct 99 XJ8 Valve Cover Gasket Set was item number: NCA2515-6AE at $110.95, plus shipping. Normal shipping to me in Florida was approximately 3-4 days. I was also told the VVT seal is part number: AJ82856, which is priced at: $31.74. I'm definitely buy the gaskets and I'll check prices on the VVT seal. (Thanks).

JimmyL - Thanks on that "other way" of getting to that bolt. I have the feeling that if I loosing the manifold, then I'll be buying a gasket. I'm running out of money, so that might be a future project. I am going to at least spray out/wipe the Throttle Body (with my new can of Throttle Body spray). (Thanks).

Regardless of all this searching and paying out money (that I don't really have), this is fun and rewarding (when it works out). Thanks for all your help, and I'm still waiting on parts. I'll keep you posted.

 

IXJIT - Here's your post you were talking about. I was reading it last night (thanks). You and Test Point had that very same discussion at that time as well. I guess Avern1 (below) has found the set (and I confirmed with JagBits) - so that's the route I'm going.

Here a thread front BRUTAL and WhiteXKR on how to remove reinstall the 99 XJ8 VVT seals.

Test Point - I know - that discoloration concerns me, as I haven't seen an engine on this site (yet) looking like that under the valve covers - embarrassing at least - a future problem, I don't know yet. I like the idea of grinding the socket, I'll look into that too - especially since I just bought a new 8mm combo wrench and I was going to heat it and bend it (like GUS did), but the propane torch I bought from ACE hardware was leaking, so I brought it back. I would also like to search out some new bolt types for the back of the Thermostat Housing to make installation/repair easier. I'll post whatever I do wind up using. (Thank you) BTW: Which is more, a "dollop" or a "plop"?

Avern1 - I Just called JagBits about that part. I was asked for the last 6 of my VIN and was told "oh, that's an earlier model", and that the correct 99 XJ8 Valve Cover Gasket Set was item number: NCA2515-6AE at $110.95, plus shipping (*Edit: Ground shipping included). So what you said is correct. Normal shipping to me in Florida was approximately 3-4 days. I was also told the VVT seal is part number: AJ82856, which is priced at: $31.74. I'm definitely buying the gaskets and I'll check prices on the VVT seal. (Thanks).

JimmyL - Thanks on that "other way" of getting to that bolt. I have the feeling that if I loosing the manifold, then I'll be buying a gasket. I'm running out of money, so that might be a future project. I am going to at least spray out/wipe the Throttle Body (with my new can of Throttle Body spray). (Thanks).

Regardless of all this searching and paying out money (that I don't really have), this is fun and rewarding (when it works out). Thanks for all your help, and I'm still waiting on parts. I'll keep you posted.

 

You, obviously have one of those AJ27 engines that Jaguar was still using AJ26 parts. December 15, 1998 engine assembly.

A great suggestion that came from someone on another forum, JagTechOhio I believe, is to use a large pair of pliers and break off hunks of the thermo tower until you can get to the bolts. It is going into the trash anyway.

There are 8 dollops in a plop.

 

tempest,
Try Welsh 1-800-875-5247 for the VVT seals. I just bought 2 of these from them during my tensioner replacement. Can't remember the price, but it had to be cheaper.

 

I agree about the engine build issue. I appear to one of the "on the edge" owners. The triple 6s in the VIN should have warned me. LOL

I *can* break that Thermostat Housing apart (I read that post as well). It would be fun - I just might not stop there - LOL. I actually discussed that one last night. I'm going to stare at this mechanical manipulation for a bit today.

Some of the ideas we have so far:

• Raise Manifold Slightly to Give Wrench Clearance (Does this process lead to the possibility of unseen manifold gasket unseating?)
• Break Thermostat Housing (Surefire method for removal, but doesn't give any clear access for bolt installation without modifying new bolt with "cut" for screwdriver use during installation - and still requires a wrench to torque - so access is still an issue)
• Grind Down a 8mm Socket (I like this one and want to look into more)
• Heat and "Bend to Fit" an 8mm Open-End Wrench (this takes additional experience and supplies)
• Buy a "not to easy to find" 8mm 3/8 Inch Drive Crow Foot Wrench (prices are: Snap-On $17.35 (+shipping); Home Depot doesn't carry them; Jupiter, FL NAPA store does, but are currently out of stock (price unk); and I'll keep looking. (I am concerned, maybe without cause, that an open-end wrench has too often stripped the bolt-head - this we cannot have). A six-point open-end would be great (harder to find).

...dollops and plops...this book didn't help (below):

 

RAE - great advise on the VVT Seals. I called WELSH Enterprises, Inc. This part is NOT listed on their website (they said this part was too small to list). They are $10.95 each (shipping was stated as "about the same $10.95). That's a great price as I've already seen a standard price (Ebay, etc) for $23.00 (+ shipping). So that's "in the bag". (thanks)

 

@Tempest

You asked about the brown coloured film. That is varnish from oxidized oil.

It can be reduced over time by more frequent oil changes.

It can also be treated by adding a quart of ATF to your oil before the next oil change, warming up the engine at idle, and then draining.

What was the oil change interval that you normally use?

 

Thanks everyone! That's done. The project was to upgrade the thermostat housing to the new aluminum housing due to a breakage at the upper hose "nipple" or thermostat cover. While I was "in there" I wanted to see which secondary timing chain tensioner was replaced by the dealership where I bought the vehicle. It turned out that the right side (passenger side) was replaced - I did the left side (driver side).

Fears:

• Never Having Done This Before
• Keeping Within a Budget
• Not Having the Right Tools

Comforts:

• The Jaguar Enthusiasts Forum
• Plenty of Time
• Some Mechanical Knowledge

From my first post in this thread, I took everything down that I was going to work on. Noticed a really crappy brown stain inside the cam housing and thought it might be burned oil. Thank you, PLUMS for enlightening me about the oil oxidation. I will be changing the oil within the next week, and will continue to "watch it" on the dipstick (where I noticed that it never really looked like good oil when I check it).

After all the parts arrived, I started on the Thermostat Housing. That was pretty straight-forward, in that I had TWO REAR bolts that I couldn't reach. I decided to combine ideas. So I took an 8mm socket and ground it down with my dremmel tool and then ground a notch at one corner so I could use and extension at an angle. Then I bent an 8mm wrench very slowly with vice grips. Why do both? I knew that the open-end wrench would not be able to torque that bolt without stripping it, and I knew that the socket wouldn't have the clearance as the bolt was coming out. Here's the pics:

Bent 8mm Open-End Wrench:


Ground Down 8mm Socket with a NOTCH for the Extension:


That ground down socket "did the trick". After I broke the bolt free, I used the bent wrench (with vice grips attached) to turn the bolt free and lifted it out with a "magnet tool".

I did spray the Thermostat Housing black with a high heat resistant spray paint ( $6.00 at Pep Boys).

With gaskets and sealer applied, I reversed the process of putting the bolts back in the Thermostat Housing and had no problems at all. AVERN1, I paid close attention to that Thermostat cap and O-ring, but after I tightened it down, there were no leaks.

Now, on to the Timing Chain Tensioner:

Zip-Tie Method Used -

1. First thing was to turn the crankshaft to align the "flats" and release pressure off the cam lobes - did that.

2. Next I had to "Zip It"...


3. Then loosen the cam caps and take them off - keeping them in order.


4. With one hand on the camera and one hand doing the work, I removed the old Timing Chain Tensioner. You can't actually see it, but as I was moving the cam shaft and timing chain, the tensioner basically fell out:


Here's the notorious Timing Chain Tensioner, complete with crack down the center (booooo) - Not a bad crack, but it was well on its way to failure:



5. Then I dropped some oil in the center hole of the new metal bodied tensioner:



NOTE: Here's the size difference of the NEW Timing Chain Tensioner Bolts Versus the OLD Timing Chain Tensioner Bolts:



6. Then I torqued the tensioner bolts, oiled and reseated the cam shaft, oiled and replaced the cam caps, torqued the bolts (lightly and evenly starting from center and working outwards). Here's the new tensioner, pin still in and zip-tie still in place.



7. Then I pulled the pin out of the Timing Chain Tensioner, cut the zip-ties. Yea!

8. By this time, I was pretty excited to have that done, so I didn't take photos of the Cam Cover Gaskets - it was a bit tough to get all those bolts back into place and I made sure to use a DOLLOP of gasket seal where the seams of the front timing chain housing met the cam shaft housing. NO LEAKS TO REPORT after two hours of driving.

NOTE: The VVT Seals - Well, I checked the part number: AJ82856 is listed at Car Parts Discount as item number: 269425 at a price of: $ 7.90 each. I bought two and shipping to Florida was: $ 6.95. Yes, they are in, yes, they fit.

NOTE: I did lean on, and brake a $26.00 coolant line that led from the upper radiator to the overflow tank "Tanks alot Jaguar". LOL

NOTE: After driving for about 20 minutes, I received a "RESTRICTED PERFORMANCE" light and the codes were: P0172 and P0175 "LEAN FUEL". I didn't tighten down the hose clamp for the ribbed hose from the air filter to the intake. After tightening the hose clamp, and clearing the code, all is well.

NOTE: Here's my photos of the bolts and how they were removed from the cam cover - just in case someone might not have written in down.

Right Side (Passenger):



Left Side (Driver):



Okay, thanks again JEF members for all the help. I hope that all this isn't IT WAS SLIGHTLY NERVE-RACKING - BUT IT'S DONE. NOW I CAN GO BACK TO SLEEP.

 

Nice write-up and really nice pics ! Big improvements.

 

Very nice I think I am going to get one of those aluminum T-stat housings too. Looks like a handy piece!