If you are busy driving are you looking at the temp constantly? According to various posts on the forums, the gauge reads center until you reach 235F, then jumps to red. At that point you may be running without coolant. Are you then in a position where you can shut off immediately? I am not willing to take that chance.
Another option, which I use on my XJ6, is the Ultragauge, which plugs in to the OBD port, and monitors many functions, temp included. You can set an alarm for whatever temp you want. I like Steve's Realgauge, because I have the temp and oil pressure combination.
The factory oil gauge reads center scale as long as the pressure is over about four pounds, not good enough for me.

 

From What I understand temp gauge reads 50%(180-230F), 60% 240F 80% 250F Finally 100% 260F. At what temperature do these engines start getting hurt from the heat? I do have OCD and am always looking at the gauges, its very easy to go over the speed limit, and the temp gauge is not too far off, what I am saying is there had to be time to pull over after you notice it over 50%, which is when I immediately would pull over. I don't understand how Jaguar's engineers would let the temp warning be so late, if its going to be destroy the engine. My mechanic says he actually has seen people drive with the temp warning light on for a few miles and no damage is done to the engine. I have not owned a car without a temp gauge that does not sit in the middle.
Just my thoughts,
Please correct me if I am wrong.
Mike

 

The actual numbers are center scale (50%) 185F to 235F. At between 235 F to abbout 240F the needle will rise quickly into the red zone (within the 3-5 degree range). Does red zone mean instant engine damage?...probably not....but potential for damage will depend on how long and you are in the red zone, whitch means anything from about 239 F on up, how hot it gets, and how often the engine may have overheated on the past. These cooling systems when functioning properly should never see over 215-220F.

The advantage of RealGauge is that it lets you see the cooling system degrading (thermsotat beginning to stick closed, pump impeller wearing down, radiator getting clogged) BEFORE you actually start overheating. If you do overheat, RealGauge also has an audible alarm in case you are not paying attention to the gauge.

That being said, here is what RealGauge does not do: These engines have their coolaant temperature sensor placed high on the engine. Therfore, if there is a major loss off coolant, due to a burst hose, for example, neither the factory driven gauge or the RealGauge driven gauge will register the coolant temperature (ie; no overheat warning) since the temperature sensor will not be immersed in coolant. The solution to this is to NEVER ignore a low coolant warning. Always pull over when you get a low coolant warning and make sure you have not had a major coolant loss.

 

I have to disagree with your mechanic. It is very common for someone to not know your car is overheating with the factory gauge. I see cars coming in with a complaint of the cooling fans running long after the car is shut off & the gauge reading correct. I have the Real Gauge fitted to my XKR. You have to realize a lot has changed in 40 years. He may be quite knowledgeable on the older cars but unless he is still at a dealership he is not seeing the issues seen at the dealer level.

 

I have the RealGauge package on my car. Back in September I noticed that my water temp was starting to run a little warm. Not hot, but warmer than usual. I began checking the coolant level and watching for leaks at least daily.

I ended up finding a crack in the radiator under the top coolant hose. Correction was a new radiator.

The leak was not hitting the ground and therefore would have gone undetected except for being able to monitor my coolant temp accurately. Had the radiator crack finally split while driving, it might have been a disastrous event. Without the RealGauge, I would have thought everything was OK until that moment. Would the OEM gauge warned me in enough time to pull over? Not sure, but I would still have been stranded on the side of the road with no coolant in the system.

If this sounds like a plug for the RealGauge, it is. Cheap insurance in my experience.

 

He is currently a Jaguar specialist. He has worked at the oldest Jaguar dealership in Illinois for many years.

 

So does all three of my Jaguar's have the same problem?
The X-type did overheat but it gave me fair warning.

 

I have only studied the XK8/Rs and the X308 (up to 2003) XJs. What I have heard, but not verified, is that all the models have a similar system which is center weighted, but some of the others may have a somewhat lower theshold before the pointer moves, giving you a bit more warning.

I believe all the models have a high mounted temperature sensor, so the warning about pulling over to check a low coolant warning applies to all.

 

Hi all.

We can have an endless discussion concerning water temps and oil pressures for that matter. The fact is that the temp and oil press gauges are nothing more than fancy warning lights like you have in other cars. If you are happy with that, fine.
Now, if you are more interested in what is going on in your engine and want to spare yourself possible expensive repairs. install real gauge temp and oil press mod.
As we are approaching Christmas, this mods would be a nice present instead of all the ties, socks and boring books you normally get.
They cost a lot less than my latest speeding ticket. ($ 600)
You want more presents? Get the remote top mod, or a new can opener for you with a tin roof.:icon_san tawaving:: icon_tree:

 

3) Short trips are really bad, as you oil will never get up to temperature, so any excessive fuel/moisture will not vaporize, and will start to build up in the oil. I don't know how many trips are within 500 miles for you, but the shorter the run the worse, as during the 1st minutes from a cold start the ECU is spraying lots of extra fuel. But as you refresh your oil after 500 miles anyway (indeed it makes no sense to use expensive synthetic here), it may be not as important.
4) Drive! After a couple of short trips take a long one, where the engine oil and gearbox oil gets to operating temps. So do yourself and your car a favor and take trips of 100 miles or so at least a couple of times per year.

 

so why should I upgrade?

One of your concerns was not over heating the Nicasil engine. Does your temp gauge quickly rise to and sit at the factory set 1/2 way mark and just stay in that position for the duration of your drive?

I was also under the impression that the gauge was showing me some useful and re-assuring information IE, The 1/2 way safe area. Not the actual temperature at all.

With the real gauge showing real temperature is much better as should it rise above my known safe needle range I could take any necessary action. I feel it is cheap insurance.
Follow WhiteXKR's link to thejagwrangler for full specifications.

Bottom line is I don't trust the jaguar system to give adequate warning.

Hope this helps a little.

 

Oh dear so much advice all written to be helpful but .......
You have a 2001 XKR Silverstone. You do NOT have a Nikasil engine they were discontinued in 2000. You do NOT have the early water pump you have the later design that does not fail prematurely. You have a metal thermostat holder , all Rs do
Thermostats fail closed, you do get some warning that is the fans coming on once the car has stopped (not unusual if hot) but in a cold winter 32 degrees it is a warning If the car goes into the red it is already too late, stopping will not necessarily save your engine as it also stops the air flow. This is low likelyhood the most common reason is actually fan failure. If concerned get a real guage

 

I am almost 100% certain I have a Nikasil lined engine.
Date of manufacture(My Car)-8-14-00
Date Jaguar switched over to steel lined engines 8-18-00

 

Where are you getting this date? From the Date on the door jamb below the B-pillar or from the number on the engine? The date on the door jamb does not indicate age of the engine and in some countries not even manufacture date for the entire car.

The engine number is the only reliable method for what you want to know. A search on the forum will show you how to read it and it will tell you down to the day and time it came off the line.

 

Jag#4, you're right of course, he should be reading the engine number. But it is unlikely a car built 8/14 will have an engine built after 8/18.

 

I have the BUILD sheet from the car and have looked up the engine number. I am an engineer....I have looked into this.

 

I have the build sheet, of the exact date the car was built. I have also looked up the engine number. I know what kinda of engine I have.

 

JaguarXKR.
While most of the advice that has been offered has been valuable, as someone who has 135,000 miles on my 2002 XKR (75K of which I have put on in the last 4 years), I am sure you will have time to pull over and stop if your gauge goes into the red, if you do it quickly. It has happened to me on a couple of occasions where a hose or nipple has broken and I could smell coolant burning as well as my temperature gauge went straight to the red zone. Our temperature gauges don't really measure temperature, ( I wondered why my gauge never ever moved from the exact center), they are more or less an on and off switch that tells you that your cooling system is working or not. The first sign of a bad thermostat will be that your fans will go on almost immediately and stay on after you shut the car off. Your car will not overheat but you'll notice the noise of the fans going on at inappropriate times. I have replaced the thermostat a couple of times (even the newer ones fail), but each time I have had the fan warning. Besides, you state that you drive 250-500 miles per year, obviously, your typical drives are extremely short distances. You will have enough warning, I promise you. These engines, Nikasil or not are extremely hardy engines and so long as you have taken care of the tensioners issue, your engine issues should be eliminated. You will have the usual traction control/abs idiot lights, maybe an airbag light warning, and if a convertible, hydraulic hose leaks, but normal maintenance will keep your car running very well for many thousands of miles.

 

You are correct. I guess that's what I get from reading his post too quickly.

 

Have a 97 xk8 and in cold weather driving my coolant temperature gauge goes down...And the heat is less so hot, Why?