Hi All,
I've owned my XJ6 from almost new (bought in early 1997). I have maintained the car in top condition ever since.
It has about 165,000 miles so far. This past Friday the 13th I was driving in extremely hot weather and notice my temp gauge going crazy almost approaching red zone.
I stopped and added coolant and continued. Soon my temp gauge was going crazy again indicating overheating just below red zone.
However my overheat warning light did not come on at all. So I checked into a motel and waited until next morning.
Went to drive it again and again the temp gauge indicated overheat but no warning light.
I found a local shop that said they could fix it so I suggested they replace the thermostat, coolant temperature sensor and give the system a coolant flush.
They called me couple of hours later and said they pressure tested the system and discovered a coolant leak under the intake manifold that they had to fix.

I picked up the car when they were done and it seemed to run great with temp gauge indicating normal.
Well today I took it on a long drive and on my way home I stopped and noticed steam coming from my hood.
The temp gauge indicated normal temp.
I drove it the few blocks to home and the warning light came on about a block from home.
I investigated and found a ruptured hose right behind the intake manifold.

What is mysterious is that the temp gauge never indicated overheating.
Could this be a bigger problem or is it just a hose failure? Seems like the temp gauge is not working properly.
Fans seem to be coming on. Water pump seems OK according to the shop.
Here are some photos. What hose do I need to order? I can't find any parts diagrams that show me hoses and routing.
It's the hose right behind the rear of intake manifold that appears to go into the head.
Seems to me this may have been the hose the shop fixed? Did they use the wrong type of hose?
Or is there another hose running under the intake manifold?
Thanks!

 

Look familiar?

https://www.jaguarforums.com/forum/x...-today-109984/

BTW, welcome to the forum! Be sure to go to the new member area, read the guidelines, and make an introductory post so you may make full use of all the great things this site has to offer.

As far as I know, there is no coolant overtemp warning light on the X300. There is a coolant low-level warning, perhaps this is the indicator you are talking about?
The temp gauge is notorious for having a VERY! broad middle range. Seems from 180F to maybe 220F or above it exhibits precious little, if any movement about the middle mark. Mine (well, at least the one on the 95, the only one tested thus far) taps red at 250F. How do I know this? You should avail yourself of an OBDII adapter in either bluetooth or wireless technology such as your choice of mobile device will accommodate. Many, myself included, are reasonably pleased with the Android app called "TorquePro" and the <$15 Chinese knockoff ELM 327 BT Adapter. Anyway, for very little capital investment, you can read your coolant temp and many other powertrain control module parameters in real-time!

 

Thank you for your reply! It now occurs to me that perhaps my engine was not overheating at all.
What I think happened is the hose sprung a leak and sprayed coolant all over the engine which then turned into steam.
The warning light I think was to indicate a low coolant level.
I'm now suspecting that maybe the shop put a cheap replacement hose on.

 

Possible that he installed the hose without a clamp? There is a small coolant hose that ties into the underside of the throttle body, and then immediately exits. There are metal barbs, perhaps it wasn't clamped down and fired off?

 

Question: It is the heater hose. The last section that enters the head. It seems like this is listed as a separate part #mna6728aa
This leads me to believe that I only have to replace this last section of hose?
See photo. It's the section of hose (in photo) that is disconnected from head and seems to be connected to the formed hose

 

This odd formed hose is a 2nd electric water pump circuit for the cabin heater core or matrix as the British call it

The coolant hose paths are on page 57 of the 3rd doc

http://jaguarclub.sk/service/aj16_service.pdf

http://www.jagrepair.com/images/Trai...20-%202000.pdf

http://www.jaguarclub.sk/service/x300.pdf

 

Thanks! What I need to know is can I just replace the last L shaped section that goes into the head? They are listed as two separate parts.
The leak is occurring only in this hose near where it clamps to the head.

 

You can get a straight hose at any auto parts store and splice it in

I spliced mine and will have to look under the bonnet to refresh my memory , I seem to have a spot of stumble under my bonnet

 

What kind of joint connection is it between the formed hose and the last section?
Is it a quick disconnect joint or a crimped joint or threaded?
I ordered the last section of hose from dealer and dealer could not tell me what the connection was at the joint joining the hoses.
Is that a quick disconnect? Does it require special tools?

 

I believe it is a quick connect and this is the tool, but I am sure it can be done without (don’t know how however!)
https://www.britishparts.co.uk/class...ease-tool-p377

 

I got a better look at the quick connect joint from a photo of a complete hose out of the car.
Seems to me that you can carefully pry open each spring tang and get the hoses apart.
I asked the advice of a professional mechanic friend and he said that would work on this type connection.
Just hope I don't break the tang.

 

My recollection was just twist and pull. I know I did not employ any special tools to separate or reconnect it. Yes, the heater hose from head to quick-connect is a stand-alone part; P/N should be listed in the link I put up above, as well as some sourcing options - or at least in the attached pdf. It, along with the 4-ended medusa pictured in post #11 above are the two most expensive hoses on the NA AJ16.