I am ordering a few simple things (e.g. new fuel cap) from Rock Auto as I cant find the fuel cap on FCP euro, and it is ten times the price at JLR - well, do I need to pay that for a fuel cap???
https://www.rockauto.com/en/moreinfo...=5900&jsn=5125
vs.
https://www.jaguarparts.com/oem-part...bC12OC1nYXM%3D

So thought I would / might also get a Thermostat while shipping. I know this is not the Aluminum one, but thought I might ask which of these two would be best, or would you be saying don't under any under circumstances...
https://www.rockauto.com/en/moreinfo...=2200&jsn=6098
or,
https://www.rockauto.com/en/moreinfo...=2200&jsn=6099

I could also get the sensor...
https://www.rockauto.com/en/moreinfo...choice=0-0-1-1
https://www.rockauto.com/en/moreinfo...=4748&jsn=6110
(SMP seems a US based company in Indiana.)
or,
https://www.rockauto.com/en/moreinfo...=4748&jsn=6104
(Wells seems a US based company in Wisconsin, I like to support US companies, not chinese ones)

I am gradually trying to target the known weak areas by way of preventative maintenance. So while I am shipping from them is there anything else that forum members believe would be a good purchase for preventative maintenance that Rock Auto would have of acceptable / good enough quality for a 3.0 litre S/C? FYI - I have already replaced valve cover gaskets, alternator, brake pads and battery since buying this car.

To that end I know I need a new coolant tank. Is VAICO a good enough brand? I've heard good things, but also some warnings? Any views...? (I've heard they say German company, but may well have operations in Finland and / or China? Ugh...)
https://www.rockauto.com/en/moreinfo...10457&jsn=6120

I prefer to get the more expensive and / or more important parts from FCP Euro or JLR due to the quality, importance and warranty - so please chime in if you think some of these parts should come from them rather than Rock Auto !

BTW - for those wisely replacing coolant pipes, here are some clamps I noticed from FCP Euro in their coolant section? Good quality?? I've heard everything from FCP has lifetime warranty, I think...
https://www.fcpeuro.com/products/hos...mubea-sc343812

 

Not sure why you would replace the clamps? Are they leaking? The one you linked is the nice constant tension clamp design.
I want to eliminate any and all plastic I can in the cooling system. But it's your choice.
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Very good point; I know a fraction of what you do...! - and am learning as I go, so thank you - may well be mistaken as not needed when eliminating plastic pipes..

 

FYI - I will probably not be ordering a Vaico coolant tank...

https://cleanaudi.com/2016/01/10/vai...t-tank-review/
and see post by Blue Bandit on this one too: -
https://www.e46fanatics.com/threads/...vaico.1014562/
and,
https://askingyard.com/is-vaico-a-good-brand/

 

Now I don't want to insist that the only way to go is the metal versions. That's just my opinion!
Yes leave the clamps alone they are not a problem. Won't hurt anything to replace them so if you want to go a head!

As I said it's up to you and now that your aware of the problem I doubt you will have any problems? You will keep an eye on the coolant level and also keep a sharp watch for any coolant leaks. That's what bites people and destroys engines. They just won't check fluid levels or even open the hood. Many, many cars operate just fine with the plastic cooling parts. BUT they are a risk.
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Thank you, Clubairth - much appreciated, and I agree with you on all of this. Firstly I think X351's coolant pipes should go to metal all round, if possible and, until then (and even after installing), with these cars it is best to pop the hood frequently to check the coolant. When I bought my 2013 XJL, I learned through excellent folks on this forum that the front pipe (with the seam) had already been replaced by the dealer, with a plastic pipe that does not have that seam. My tech said it all looked good save one very small leak on the pipe on the driver side at the top which we replaced with JLR. Still I agree with you and other experienced listers like Thermo, that the only sure fire way to go, is to replace all with Metal, which I will do when I can get them all - and then check the water pump and consider a metal thermostat too. Until then I have gone ahead and bought a new thermostat from MotoRad and WVE Temperature Sensor as both are reasonably good brands. My thermostat may be fine (or nearly fine), but my desire / hobby at my advanced age, is to gradually get my X351 as good as possible through preventative maintenance / replacing parts that aren't quite perfect, as well as getting a good scanner to go deeper, as these cars are so good that I believe they are worth it - and, it is such a shame to see so many damage the AL engines by - as you rightly say- not being bothered to keep a close eye on the coolant. Given these are quiet, smooth 170 mph + cars (without the limiter), checking the coolant is kind of the least you can do IMHO.... :-)

On another subject you may find interesting - tire choices and how it impacts the characteristic of the driving experience. When I had all 4 Pirelli P Zero on it, the car really drove like a 4 door Ferrari - stiff, hard ride, lithe, fast, etc. She just felt "alive" !! Now that I have put on much softer grand touring tires I don't get the bad ride, but I miss the alive OMG feeling. So I have come across the reviews on these Max Performance, Summer Continental Extreme Contact Sport 02 Tires, which unlike Michelin Pilot Sport 4S actually ride well also - I mention in case someone else gets tempted and can report back with valuable intel!!
https://www.tirerack.com/tires/tests...y.jsp?ttid=329

As it's normally always been you can have more comfort, but then not a sporty ride too. That tire starts to break the mold perhaps? As might to do the new Vredestein Ultrac Pro and perhaps also the Pirelli P Zero AS 3. I think it matters, because the reason I'm excited by all your great X351's, as it is the first car I've driven since the older classic Mercedes CL models (140, 215) that feels like "2 cars in one" - silent cruiser when you want that, and a sports car when you want that.... Here are the two other tires, in case forum members are interested that may assist in that regard, as I now know changing tires on an X351 can make a massive difference to the ride: -
https://www.tirerack.com/tires/vredestein-ultrac-pro
and
https://www.tirerack.com/tires/pirelli-p-zero-as-plus-3

Thanks !

 

Glad you enjoy your XJ! Tires are a lot like oil there are a multitude of choices and a lot of arguments! I use what I use but won't insist it's the only choice.

It certainly been the best car I have ever owned. As you said a wonderful luxury car that has no problem just idling along with traffic but there is an animal hidden underneath!
Just a note? I race a bit and have taken my XJR to 180+ and it was surprisingly a non-event? Car did not seem unusual in any way? It does make you feel a bit disconnected as car and road are moving unlike anything I had seen before.

One funny story is I drove across county (Man is this a highway cruiser!) to see my Mom and show off my Jaguar a number of years ago. Took her out in the desert and made a quick run up to around 135 mph. When I told her how fast we were going she did not believe me! Can't be she said to quiet and smooth.
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My goodness!!! 180 !!! I do agree that it certainly hides it speed well. I have not had it over 100 mph yet, but at that speed there really is no sensation of doing anything more than e.g. 60mph etc. But yes, absolutely brilliant car. Such a shame they stopped making it. ... I went for late night drive last night and it averaged 8.9 litres / 100 km on the trip, which is about 26.4mpg (US) and 31.7 mpg (Imperial). Yesterday morning, however when the engine was cold, on a trip just running a few errands, I was averaging about 11 litres / 100 km - or approximately 21.4 (USA) - 25.8 mpg (Imperial). I wonder what that all means about my thermostat and temperature sensor, if anything?

Rather than going full electric I wonder if the X351 should have carried on as a hybrid, like the S class. Imagine nearly 80 mpg out of these !