The noise went away after I tried Sparkenzap's recommendation for pulling more coolant into the SC by pulling a small hose and massaging the intake hose for a bit. Now, all I have is a squeaking like a wet belt at start up. It goes away when it warms up.







2002 Super 8, 104k.

 

I'm confused. I thought this thread was about Bondy reporting a tap after the engine overheated, now it's Curtiss with a belt sqeak.

 

It's not usually suggested in overheat threads, but you make a good point that has a sound logical basis.

 

Thank you.

Something else that comes to mind is the potential use of Snake Oil: i.e. what ever oil additive that anyone suggests. I'm not advocating the use, but if you do, it's important to understand what they do. One type thickens with the intent of helping lubricate at high temps and startup (stp, engine honey, etc.) and the other types tend to be detergents (marvelous mystery oil, lucas, seafoam) with the intent of cleaning.

So IF you decide to use an additive, understand the downsides and precautions:

*Thickeners can conceivably make an engine quieter and lubricate better, but they can also cause extra wear/strain on the oil pump. They may also not flow through partly clogged oil passages as well.

*Detergents can conceivably clear slug, muck, etc out of passages, but if they work the bulk of that is going to go quickly to the oil filter. If the filter gets clogged, again the oil pump is in danger.

I don't habitually us additives, but on the engines I do, I change the oil and filter within 500miles of adding it for the reasons above.

One other thing that I'd say is keep a close eye on the water pump. If the cooling system lost the bulk of it's fluid, the water pump bearing's days may be numbered.

Oh, and remember: my advice is free and you get what you pay for.

 

Thanks for all your input so far. I have an update on how things stand.

Over the weekend I had plenty of time to look into some of the more serious issues that could be causing this noise. First thing I did was removed the valve cover to check out the valve clearances and tensioners. Tensioners are orange plastic type so these will be done, however the chains are tight and the tensioners look like they're in good condition. The car has only covered 50k and oil changes have been carried out every 5-7k so this would have gone some way to preserving these I'm sure.

Valve clearances are all consistent and within spec on both inlet and exhaust except 1 inlet valve that is slightly tight at 0.18mm. I don't believe this is causing the noise (could be wrong though).

Then I removed the plugs and inspected the valves with a camera. These look fine. All the valve seats are in situ. I removed the camera and checked for play in the rod bearings. I took each piston slightly past TDC and pushed the piston with a rod. No play at all on any cylinder.

So I've checked rod bearing play, valve seats and valve clearances, all look fine apart from one valve being slightly tight.

The engine is running perfectly besides this.

A little more on the noise. It is not there from a cold start. As I've said before the noise only starts after the auto choke dies back. It takes about 5 minutes to come in. It is accompanied by on occasion a very slight squeak which is intermittent. The squeak concerns me as it is a sign of a spun bearing, but as there is no play it is unlikely.

So what next?

To answer SparkyGage's query, I'm going to do an oil change but I want to check everything possible mechanically before throwing money at another oil change. Only 500 miles on the current oil. A new thermostat and coolant has since been added. The vehicle no longer overheats.

I suppose I should take the oil pan off the car and check the rod bearings visually. But this is the last roll of the dice before I take it to a specialist.

The noise is coming from around the first "E" in "supercharged" as shown below. Just to be clear incase anyone missed it, the supercharger belt has been removed. This is also above the location of the tight valve. Would 0.02mm out of spec make this noise?

http://1.bp.blogspot.com/_bBy_iItoJW...d%2BJaguar.jpg

Out of interest, to save me looking, where is the oil pump located? Is it in the oil pan or elsewhere?

 

Oil pump is behind the timing cover, have you tried removing the accessory belt to see if the tick persists? (not just the S/C belt)

 

Bondy:
You ain't gonna see any rod bearings by removing the oil pan. The engine is a bedplate design and you won't get the bedplate off with the engine in the car.

I would have a very hard time believing a "tight" valve would cause a tick and especially .02 mm too tight!

Maybe a valve guide? Or as Mr Dsnyder is implying, maybe your tick is not really coming from where you hear it?

I have heard some pretty noisy injectors, although I must say none that could be confused with a engine knock.

Good luck!

 

When I worked at the dealer another mechanic had a 'knock' in a 4.0 XJ8.

He tried a few things and finally pulled the head. He found a piston LOOSE (side-to-side) in the bore causing 'piston-slap'.

The engine got hot and the piston swelled/shrank and was loose. This was when we were replacing thermostats almost every day. I don't remember if the bore was damaged but he ended up putting a reman engine in.

Just a thought.

bob gauff

 

Interesting that you say this. This was my first thought, however the workshop manual says it is possible. What makes it difficult in your opinion? I'm more inclined to believe you than the manual, but out of interest I have to ask.

 

This is something else I was thinking. The fact the piston will swell after warming up makes this, at the moment at least, my first guess.

Got the car booked in for Friday next week so I only have one more weekend to solve this before handing it over to someone else.

 

No I haven't tried this yet. Will give this a go.

But an advanced warning, if after all this work it's this simple, I'll be jumping off the nearest tall structure.

 

Well, I sure missed something if the front crossmember is not in the way! Have a glance under there. The oil pan itself is only about half as long as the engine.

Maybe its time to turn up the radio instead of worrying about it!

 

Going out on a limb: Change the plastic tensioners . . .

 

Yeah, I think Jim, may very well be on to something. I assume you are still disassembled to there.

 

Unfortunately not, but I've got my eye in now so tearing it down again won't be an issue. However the chain was perfectly tight when I inspected it and the secondary tensioners looked good. Plus I am convinced the noise is not coming from that area of the car.

This sucks. I'd quite happily pay £££ (or $$$ for you American lads) to get the thing fixed, but finding the problem is a challenge to say the least. I am under no illusions that the tensioners will need doing soon, but if the engine needs to come out to fix the noise I'll do it then rather than before hand.

Anyway, I've booked next week off work so I have 9 straight days to solve the mystery and 7 days to cancel the Jag specialist if I find the issue before hand.

I expect after this though I'll have only a matter of hours left to save my marriage. The wife already wants rid of the car and by 6 month old daughter is forgetting what her daddy looks like!

 

Aaahhh yes. The dilemma of the automotive addictions..... I showed my recently acquired wife a 94 XJS V12 last week and she said "now this is what you need". I replied "I don't know if I'm ready to take a mistress just yet."

Take if from a guy on marriage 2.0: make sure the mrs knows she's more important than the car. Or anything else. Here's hoping the solution arises quickly.

 

Could you give us a quick rundown (numbered) of what you have checked so far?

 

Sure can...

1) Valve Clearances
2) Secondary Tensioners
3) Rod Knock
4) Valve Seats

This weekend and the following week I'll be checking and doing the following...

5) Aux belt removed then running her up to temp. (I have a scanner so I can monitor the temp before anyone panics).
6) Compression test
7) Reinstalling the rear subframe (rear end rebuild and diff replacement)
8) Timing cover off to check primary tensioners and guides.
9) Complete engine oil flush and change.
10) Taking the car to a specialist (unless I find the problem before Friday).

Got a busy week!

I'm becoming obsessed with this. The fact that the noise sounds like it's coming from the charge cooler means nothing as it's pretty much a hollow cavity, so it's just amplifying the sound. That could actually be good news.

Piston slap is a possibility but fairly rare today. Could be a warped head but the vehicle isn't overheating, no white smoke from the exhaust, so this is unlikely. If it is a head issue I'd take it on. At least I can deal with that. A full engine removal and tear down though scares the living c*** out of me!

 

Hello Bondy,

I too have a higher mileage 98 XJR and that sounds alot like your supercharger is rubbing or supercharger bearings are failing. My car has made similar nose after overheating. I recommend you take the largest screwdriver you can find ( put the screwdriver tip on the parts of the engine you suspect and listen with your ear on the handle) to confirm the noise is coming form the supercharger instead of the side of your block (piston slap or head issues). timing chain issues are most likely heard on start up but go away after running or freeze your engine solid. with your cam covers pulled you will see cracking and lots of wear (sometimes missing plastic) on the secondary chain tensions. Remember your supercharger is 15 years old and has most likely had zero maintenance. As your car heats up your supercharger heats up unevenly typically cooler in the front and hotter in the back with worn bearings this can cause the rotors to rub and generate a noise very similar to that.

Have fun figuring it all out,
Mat

P.S. Typically The supercharged Cars are more friendly on the secondary tensioner's due to the lack of Variable valve timing generating large asymmetric stab loads in the chain, But they can fail nonetheless and upgrading them regardless is a good idea. The bleed plug on top of the supercharger should be 19mm or 3/4 hex. proper beading on these cars is very important to prevent a big air bubble in the charge cooling system.