Some members have seen fans running after shutdown and have traced it to a failed thermostat. What follows is a similar condition related to thermostats. It is subtle, but real.

what it is:

a thermostat that opens slower and less fully than a fully functional thermostat

if you suspend such a thermostat and a new thermostat in a pot of water and heat it up, you will see that the new thermostat starts opening sooner and opens more fully than a lazy thermostat

symptoms:

the electric fans mysteriously run in situations where the fans would previously have been silent. for example, while parking in the garage after a light run.

implications:

It is not as dangerous as a failed thermostat as the coolant still flows after it gets to a higher temperature. The semi-idiot temperature gauge does not go into the hot zone. In fact, being the idiot that it is, it never budges. But, running hotter, longer, is harder on the engine and related components.

The thermostat should be replaced under such circumstances.

If you buy a STANT or NAPA thermostat the box will actually contain a repackaged WAXSTAT thermostat exactly the same as OEM in every way.

Replacing a thermostat is one of those things where you cannot save money by delay as it is a multi-year item that will only get worse as time passes. You might as well do it immediately.

US owners are lucky that they can be had for as low as $12.66. Shipping is a killer for everyone else.

ps. anyone choosing to test their thermostat should be careful to suspend the thermostat in the water and not let it touch the pot because the pot itself gets hotter than the boiling water ... it could overdrive the thermal motor and ruin it.

 

How difficult is it replace the thermostat on an 04 xjr?

 

There is bad info here. Just purchased stant part 13649 as recommended. Does not fit because of a ridge in housing. Went thru same thing 8 years ago. Had to go to jag dealer and get ripped for the proper wax stat unit. All the dopes selling stant unit as correct part are wrong. You would think that a company like stant in the past 8 years sine my last adventure would have figured this out. But of course everyone who has wasted several hours of your time for what have been a 20minute job will tell you they are sorry.

 

First, there was no part number offered in the original post as this is the General Tech Help section. Therefore, the advice about a lazy thermostat is applicable to all models. There was no inference that it was specific to a XJR.


Looking up the part number that you actually bought using the rockauto site, you opted for the generic substitute.

1998 JAGUAR XJR Thermostat

The major differences are in the diameter of the poppet valve and the construction of the bridge.

In other words, just because the brand is a STANT/GATES or NAPA does not mean that you can just grab the cheapest part number on the page.

I posted the part numbers as applicable to the 1998-2003 XJR in the last couple of weeks in the applicable X308 section. Again, this is the General Tech Help section.

 

Correct the the generic versions.

My experience is mostly with the older Jags but the story is similar. The Stant listings show several choices for the older Jags. Not just temp rating differences. Design differences. All but two are incorrect. Pretty rotten that they do that.

But.....

If you dig a bit and look closely at the illustrations you'll find that Stant does indeed offer the *correct* thermo....in two temp ratings.

Aside:

Does anyone here besides me exercise new thermostats before installation? Just hold it in your fingers and press the enter section against the spring. It should move smoothly, of course. If you feel a "catch" in the action press a couple more times until it goes away.

You've just saved yourself a "shop comeback"

Check ten new thermostats and I'll wager at least one binds/catches.

Cheers
DD

 

Done that ... but only out of curiosity. I'm always afraid to overstroke the motor.

Just read the other day about how to test the cracking temperature: push valve open slightly, insert thread into crack between the flange and valve, suspend in water by thread, when the thermostat pulls away from the thread, read the temperature immediately.

 

The bad information that I was referring to was that if you obtained the recommended thermostat for a 98 XJR that you would be find a Wax Stat in the box. Not true. Also checked a half dozen sites including Amazon and they all had given the recommended thermostat as a Stant 13649,,,Amazon went so far as to say this thermostat will fit your XJR.

Further research by me came up with a part number of Stant 14748. I then went to local Winchester Auto Parts and axed for this one. Was told by counter clerk that this was the wrong thermostat. I axed to see it,,,took it out of the box,,,said Wax Stat on this one,,,,and it was identical to the one that I had purchased from local Jag store 8 years ago,,,although at 1/3 of the price at 19.95.

Oh yes,,,,I checked Stant 14748 on Amazon,,,,and was told by Amazon that this part did not fit my XJR,,,,I purchased the car new,,,,car has 45,000 miles and never been touched by anyone but me and the local dealer appliance repairman. And of course Stant 14748 again in the box that I had purchased from Jag 8 years ago.

Also changed out water pump,,,,,and then found that a couple of the little vacuum sized hoses were on the verge of failure,,,,so sent wife to the local Jag store (with photos of failing hoses taken with my Iphone). Not only was she really ripped at some 75 bucks for 2 of these miserable hoses(whoever thought that the design of these hoses must have gotten a reward from Jag for the excess profits that they have earned for the company,,,,but for me,,,just a real sorry taste,,,,yes I replaced several of them 8 years and they failed again,,,,2 fittings and 3 feet of hose for 40 bucks.

Anyhow she comes back with one of them totally incorrect,,,,so sent her on another 45 minute trip this time with the old ones in tow,,,,this time she got the right ones. Wish I could bill Jag the same 160 dollars per hour(there local billing rate for airing your tires)that they bill me for services for her and my wasted time.

All and all a project that should have taken 2 hours at most,,,,took most of the whole day.

Incidentally I was not looking for cheap,,,,I was looking for what should be the right part at a fair price. Stant is not noted for being a cheap solution,,,,,but I suppose next to Jag,,,,it really is cheap even though the parts are exactly identical.

Recommendation: Be very cautious when shopping thermostats for 98 to 2003 XJR,,,,and perhaps XJ8's too.

 

Again, no part number was mentioned in the original post. And that is not the part number I quote in other model specific posts.

From the picture, it is the same pattern that has been used successfully by other members. But, it is not the one that I bought or the part number I shared in other posts specific to the 1998-2003 XJR.


You mean this:

Stant Part 14748

seventh result on google for Stant 14748

So, you had it in your hand, you saw WaxStat, it matched the part number on your original box, and it matched your memory of the part ... but you didn't buy it.

Instead, you come here and try to place the blame everywhere but where it belongs.

Again, the original post was about lazy thermostats, with an aside thrown in about WaxStat. No mention of a part number was made until you decided to come along with your complaint. Therefore, you could not possibly have based your decision on any part number information from the original post. And thus, the original post is blameless.

A search using the site:jaguarforums.com clause shows that there are at least 29 mentions of Stant 14748 made by various members.

14748 stant site:jaguarforums.com - Google Search


No. Use some common sense and be more selective when confronted with conflicting information.

 

The Gates 33948 IS A WAXSTAT made in Great Britain.
I buy them from Rock Auto or my local parts store for under $25.00.

bob gauff

 

I need some advice! I think my wife is cheating on me.Strange happenings ie. late nite tele.calls;when she goes out with 'friends she gets dropped off at the corner and walks the rest of the way; when her cell rings she steps outside to answer it, or says I will call you back later.I got the idea that I would find out what was really happening, so I offered to let her use my XK when she said she was going out to meet her girlfriend. I hid in the boot. When I was crouching in the boot, I noticed the anntena was going up and down with the movement of the parked car. IS THIS SOMETHING I CAN FIX MYSELF OR DO I HAVE TO HAVE A DEALER DO IT?

 

Apparently not sinking in. I have tried to inform members that Stant 13649 as recommended by many vendors including Amazon and Winchester Auto that I am certain of will tell you that this is the proper stat for a 98 XJR. I have said that this in incorrect,,,,,this stat will not fit a 98 XJR. Additionally too when you open the box that it comes in,,,,it IS NOT a WAX STAT. Only after further investigation did I find the proper product,,,Stant 14748. This box does contain a Wax Stat. If you wish to confuse the issue further for other forum members who may experience the same issue,,,be my guest,,,,,however again the recommended stat by Amazon and other is incorrect. If you still have problem understanding,,,,go to Amazon and put in a request for thermostat for a 98 XJR((I suspect that other models will too be affected). Perhaps then it will sink in.

 

I am still wondering what the number has to do with, when the thread is merely giving great advice about how to tell you should check/change the thermostat. By the way, Great advice, Thanks