My XJ8 has 110K miles on her. At 70K I had the timing chains and tensioners done. 30K miles later (100K) it started leaving drops of oil on the garage floor. This was due mostly to the valve covers leaking. Now the timing cover is leaking. I have it all pulled apart now and have all the new parts. I have a couple of questions for the forum:

1. How can I tell if the secondary tensioners are bad? I found some slack in the RH chain but after having to turn the engine for balancer removal I now have slack in the LH chain. I already have the new tensioners. Is it normal to have some slack in the chains when there is no oil pressure? These tensioners were replaced 40K miles ago.

2. Do I have to remove the intake to replace the thermostat housing? It looks like I might be able to get the back bolts loose with an 8mm crows foot but is there enough room for them to come out?

Thanks

 

1. a)If they are not cracked, and there is no reason to think new metal tensioners would be bad. b)Yes. c)As you are thinking, oil pressure pulls up the slack

2. a) No b)Yes!, but most of us have "made the crowsfoot from a combo wrench, using a torch, and then a grinder to shape the wrench it so we could get it in. - A better approach, especially if you are going to change from a plastic to a metal housing, is to break the old housing apart with some pliers so you can get a socket in there, then replace the bolts with socket head cap screws so you can use a "ball hex head" wrench next time.

 

Thanks Ross, the tensioners are the newer metal type. I guess they are OK.

I am changing to a metal housing. I started to break it off last night so funny you mention it today. I will do exactly as you suggest. Good idea on changing to the socket head cap screws.

Couple more questions:

1. How can you tell the difference between generation 1, 2 and 3 tensioners? Mine are metal so I'm guessing they are atleast generation 2.

2. Should I replace the plastic water distribution pipe while I have it off? Is this a high failure item like the thermostat housing? Metal replacement?

3. Are there any other preventive maintenance type things I should do while I have the front of the engine off? I'm replacing the drive belt tensioner pulley and idler pulley bearings. Serpentine belt is already fairly new. Alternator has about 30K miles. I'm replacing the water pump, thermostat, bypass hose.

4. Any tips on the timing chain cover gasket replacement? When they did my chains and tensioners at 70K miles the cover was leaking only 30K miles later. They used a Jaguar seal. What did they do wrong? Any tips to make sure I don't have a leak in the near future? I hate oil leaks.

Jordan

 

Yes, replace the pipe, and no, there is not a metal replacement. You tensioners are gen3 if they are metal.
You need to apply some sealant at the seam where the timing cover joins the head. Just a dab top and bottom. It should not be leaking, and many use the old seal without problems.
It sounds like you have everything covered, but new plugs are inexpensive and wouldn't hurt.

 

Thanks RJ, I bought some new Bosch plugs. It looks like Bubba over torqued last time. I'm also replacing the drive belt idler and tensioner bearings. Bought them for $10 each.

Jordan

 

Is there a seal on the dip stick tube? Anyone???

 

I have run into a bit of a problem with my timing cover seal project. I'm using Victor Reinz gasket set JV5084. This gasket set doesn't fit the cover perfectly like the Jag seal does. Bottom corners of seal are square rather than round. Also, a little further up the bottom seal from the bottom corners is another rectangular section that doesn't have a slot to fit in in the cover. Other than these differences the VR seals look higher quality than the leaking Jag seals I took off. Jag wants $90 for their seals. The VR set only cost me about $25. Is there another VR seal set that is more correct than JV5084? Pictures of the Fel-Pro set seem to have the same issues as the VR. I'm thinking of just cutting the bottom seal and using RTV in these areas. Advice?

 

 

From your photo it looks like you would still have a perfect seal w/o any need for cutting or RTV.

 

You were right Jim. I didn't cut anything but I did use a little RTV down in the corners at the round holes. I have it up and running now and have been driving it around with the hood off. No leaks at all from the timing cover but now my oil pressure sending unit is leaking. Guess it was leaking before, just couldn't tell it with all the oil from the cover.

 

RJ,
I put everything back together to start with with the original pipe. Did that only because I had to order the pipe. I pressure tested the cooling system and had a small hair line crack in that pipe. You sure called that one right. I have the new pipe on now and all is good.

Jordan

 

Ross,
Thanks so much for this suggestion. It worked out great. I bought 4 6MM-1.0 X 20 allen head fasteners. These are just a tad shorter than the 6MM-1.0 X 25 hex head fasterners that were used by Jag. They were easy to install with a 5/32nd ball end allen driver. If I ever have to remove this housing again it will be easy.

Jordan