Hi fellow Tragic Jaguar Owners Club members. I have a US spec 2021 F-Type R ragtop that has trouble keeping pressure in its rear tires. The car was delivered in April and has about 1000 miles on the clock.

The recommended tire pressure is 37psi front and rear. The rears lose about 10psi over the course of a week or so. I’ve never had wheels that behave this way.

I took it to a specialist wheel shop for a checkup and they found no cracks in the rims or leaks from the tires, beads or valve stems.

Anybody else experiencing this behavior or have any suggestions? I’m not a big fan of the Pirellis and that may be the problem.

Thanks for any help.

Phil

 

The P-Zeros are horrible tires, but they aren't so horrible that they should lose any pressure over such a short period of time. I had P-Zeros on my car for the first 7,000 miles and I would go months without making any adjustments to them. Something is very wrong. I right away think it's the valve stems, but if that's been ruled out, as has the beads and the wheels, I think I would take the car to the dealer and have them address the issue under warranty.

 

I have about 3,000 miles on my 2021 R-Dynamic P380.
The stock PZeros have lost no pressure front or back since I got the car in February.
Clearly some thing wrong with either the wheels or tires.
Eve with a relatively slow leak like yours it should be possible to see the problem if the wheel is immersed in water.
Perhaps you hit 2 nails first time out!! I have had leaks like you describe when a nail was actually stuck in the tire.
Back to the dealer!!

 

I've had nails (screws, actually) stuck in the tyres of two cars I've had, and both occurred within the first week of taking delivery. Fortunately, both holes were pluggable, so a nice cheap repair.

 

If both tires are losing that much air that fast it should be easy to find. Have you tried putting soapy water on the valve stems and around the bead of the tire and then checking for soap bubbles?

 

That is what I would do. A spray bottle of windex will work in a pinch.

 

I would do it the old fashion way. If you have a wheel barrow. Fill it with water. Jack up the car, take the wheel off. Submerge the wheel. Once you see bobbles coming out off the wheel, you have located the problem.

 

Not sure which dealer you have been to, but I bought and have my XJ maintained at North Atlanta JLR and use Pete Alveras as my service advisor. He is very busy but exceptionally knowledgeable on Jaguar and his tech team has Matt, who is one of the highest rated techs in the US. Also, Keith the shop foreman is as smart a tech as I have ever known. They should be able to help you.

 

If happening to both rears at the same rate it could but also be very unlikely to be a tyre beading problem.
I suspect you have faulty TPMS valves installed in the two rear tyres.

 

Easy to check the TPMS - just get a $3 tire pressure gauge or visit your local gas station ir pump..

 

I just bought a 2021 R model, as well, in late April. I currently have about 750 miles on it and no tire pressure problems. The TPMS gadgets in the rear tires could be faulty, but both "leaking", somehow seems like a long shot. Cracked wheel(s) could be the problem, C7 Corvettes have had issues there if bad enough roads have been driven on. A nail/screw in both rear tires at the same time could be, but again, having both rears losing the air pressure you're stating, that is a serious leak. If it were my car, I wouldn't fool with it any longer...assuming you bought the car from an authorized Jaguar dealer and this is their "halo" model, I know my dealer would be all over it. They should find the problem, with the last resort of removing the wheel/tire assembly, each side, jacking up the air pressure to 45+ pounds and submerging it in water. ANY air leak in that assembly has to absolutely show with that test...and the dealer should be happy to help you out! Good luck!

 

Both of the Maserati's we've had lose air on a regular basis. Both have had Pirellis, the first the same as the jag and the current one on PZero all season. Different wheels also.

 

Funny that you should mention that issue. I have had my 2021 for a month now. So far I have only put about 350 miles on it. I have also noticed the tires losing pressure, although not as significant as 10 PSI.

I have two dial type, ANSI Certified tire pressure gauges. One kept in the car and one for the garage. The digital readout in the car from the TMPS reads within 1 PSI of the gauges. I check the pressures early in the morning with the ambient air temperature of around 60-65 degrees in my garage.

I started by setting the tires at 38 PSI cold the day I took delivery of the car. All four tires lost 4-5 lbs each over the last few weeks. I topped them back up using a bicycle pump. But in the last week, they seem to have stabilized and consistently read 37 PSI at all four corners. I'll keep an eye on them but I think the problems has resolved itself. Could the issue be related to the tires breaking in and the seal to the rims "mating" more completely ? I have never experienced that phenomenon on a vehicle before. I can't remember owning a set of Pirelli's before either, maybe it is just some quirk of that brand and style ?

I do check the tire pressures on my vehicles regularly and inspect them for nails or other foreign objects and generally any pressure change not related to a leak from a puncture is the normal and expected changes due to winter driving at 40 degrees and summer driving at 90 degrees temperatures.

 

We experience 'porous' alloy rims on an Izuzu back in the '90s.

We have also seen corroded alloy rims on our daily drivers (should not the case for a NEW car of any make).

I'd go back to the dealer to get it resolved. 10LBS/week could be dangerous, and cause premature tire failure due to low pressure running (extra flexing).

 

I put about 120 miles on my car a couple of days ago, a combination of freeway and city driving with the outside temperature between 80-85 degrees, I checked the tires cold yesterday morning and they were 37 PSI all the way around. So it appears that my problem has solved itself. But I'd sure have a dealer check if I were losing 10 lbs.

It would probably be a good idea to cross check the TMPS readings with a good quality tire pressure gauge and not a cheap pencil type. A good quality gauge whether dial or digital can be had these days for $15-$30 and every garage should have one.