There has been a rattle from the front of my 06 SV8 when cold ever since I grounded the IC pump relay coil so it runs, replaced the water pump, replaced the auxiliary pump brushes so it runs, and tightened up the three mounting nuts on the air suspension compressor. The rattle sounds like it is either in the dash or the engine bay and today as I watched the temperature on the UltraGauge, the rattle stopped abruptly one mile from home when the temperature reached 141 degrees F. The air compressor had run before then and had a pretty noticeable vibration since I tightened up the three mounting nuts. The rattle did not come back on a short trip to the post office and back.


Is there any device on the supercharged engine that might rattle until the temperature hits 140F and then change state for the rattle to stop? Or might that temperature just be a coincidence? The time before that it rattled from cold my wife thought it stopped when I made a right turn, but I AM sure that was just a coincidence. It seems to take about a mile to stop rattling and then the rattle does not come back until it is started from cold again. I am pretty sure I didn't leave anything loose when I replaced the radiator lower cowl and I assume something loose would be a constant or intermittent rattle - not just a when cold rattle unless it is a heat shield and that seems like it would be from further back. There is no undershield on the car - just the lower radiator cowl/splash shield.

 

UPdate: No one answered, but after letting the engine warm to operating temp before driving off, I still had the rattle and concluded it is in the air suspension compressor and was loud enough that I couldn't tell the compressor was running at the same time. When I reinstalled the compressor after replacing the piston ring it looked like the body would contact the mounting bracket if I tightened the nuts all the way and apparently it does. I had tightened them on advice from this forum when I had the splash shield off to work on the cooling system so I will try backing them off again and see if the rattle goes away.

 

Hi take a picture of the compressor mounted on the car and also of the mounting points so we can see what the problem might be

 

I found just one photo of the compressor on the car after the piston ring replacement and it was taken before I ran the nuts up all the way. The other photo is the compressor on the bench up side down with the bottom bracket attached.

Note in the installed photo the tears in the bottom of the fender liner where I hope to reach the nuts with the wheel turned inward without taking the splash shield off again.

I'll try to get another photo while they are still tightened up, but there may not be a good vantage point now that the radiator splash shield is installed.

 

OK,.... Before and after photos from this morning but hard to tell the difference. I backed off the three compressor mounting nuts three turns each or 1/8 inch and on a test drive there was no more rattle and I couldn't hear the compressor run, although I am sure it did.

The outboard nut is the hardest to reach being directly above the horns and I had to drive the left wheel up on a block, turn it all the way out, and wiggle under from the front to even see it. It is the one the socket is still on in the after photo.

I guess my initial intuition to not run the nuts all the way up was the right one for this particular car.

 

That don't look right have a look at the larger picture and you will see how the spring should sit JAGUAR X350 AIR SUSPENSION PUMP C2C27702 BRAND NEW | eBay

 

http://images.sngbarratt.com/product...1352174f26.jpg

 

http://images.sngbarratt.com/product...1352174f26.jpg this may help

 

Some info from the workshop manual for you too.

 

Have you got the spacers fitted that this video shows at the 3:30 mark?

 

Picture of the spacers

 

I had a rattle in the front when cold also for months, but would disappear after driving for a long while (ie car hot).

I was worried that the issue could have been the worn out control arms, but it was the bushes instead. After replacing the lower and upper control arm bushes as well as the anti rollbar's, the rattles disappeared for good.

If you haven't changed your control arms before and have driven high mileage, you can most definitely suspect the front suspension bushes. Jaguar never used to sell bushes by themselves and you'd have had to buy the entire control arm for that. But lately, perhaps now that their mechanics are getting wiser, they are now selling OEM bushes on their own.

Check if yours aren't worn. Otherwise take it to your local suspension specialist instead of Jag mechanics. That saved me 50% of Jag Service Shop's hefty bill.

 

I looked back through my compressor rebuild photos for a pic of the mounting component stack but didn't find one nor did I mention it in my notes. I think I looked at the manual procedure as well as Andy's instructions and the video

You Tube

, and did not note any missing parts. If the top spacers were missing it could allow the nuts to raise the compressor too far on the studs, but I just don't remember and can't tell without taking it off again. Looking at the pic of the eBay unit, it appears the top spacer goes above the compressor bracket and not under it next to the rubber bit - is that right?

The compressor did seem way too close to the brackets above it when I reinstalled it which is why I had not tightened the nuts all the way in the first place, and there was some sticky black rubbery substance on top of the compressor that I first cleaned off but later concluded was there to further isolate it from the bracket and put it back on before reinstalling it. In the video posted here, the reinstalled compressor's stud length below the nuts is much less than mine were when tightened up and even less than mine are now with the nuts backed off three turns from tight and washers added between the nuts and the brace, so that compressor must be lower on the studs than mine was and still is.

So....what keeps the stack from compressing too much when you tighten the nuts? Is it the two smaller diameter spacer bodies coming together? If so I may be missing one spacer or my spacers are shorter than those shown on the eBay unit. I am pretty sure the larger flat diameters of my spacers are smaller too.

I took a longer drive yesterday and there was still no rattle or compressor noise I could detect so I guess I'll let it ride for awhile. I do thank everyone for the input, diagrams, videos, ect - they are all quite helpful. I do wonder if there were changes to the mounting hardware along the way, if mine deteriorated over its 10 years, or if it was substituted by the previous owner. No way to tell if the compressor is a replacement, but there are a lot of other bodges on this car that I am working through.

 

Yes, I do have clunks in the front end over pot holes or rough patches that point to bushings and my next job will be to check the air shock bottom bushings. Others look warn as well at 134,000 miles. I have replaced the front anti-roll bar bushes, engine mounts and transmission mount and am working toward the other bushes.

This rattle was unique in that it was on smooth roads and always shortly after starting out and it started after I had done cooling system work with the splash shield off and had also tightened the compressor nuts while it was accessible.