I have a coolant leak coming from the top of the engine on my 1998 XJR. For the life of me I cant find where the leak is coming from. I have shot a video showing the coolant leaking down the right side of the engine manifold and of the steam rising from the front of the engine.

https://www.youtube.com/watch?v=Nriyrwd4qhU

I have not been able to get a mirror or a scope into the cracks to visually see where the leak is coming from. Where do you suspect it is leaking from?

 

Lots of possible places.

Have the 2 hoses beneath the super charger ever been changed?

 

No they have not. Do you mean the heater hoses?

 

Yes, the heater hoses. But there could be other hoses leaking down into that area.
Might you have access to a scope? This would be my next suggestion is to get a scope down in there for a better look.

Also, doing a pressure test might help if you can spot a texas gusher somewhere. I just had a hard to find leak until I added pressure, then it became very obvious.

 

As Water Dragon sez....there are many 'possibles' on anXJR and as these cars rack upo the miles and the service hasn't kepy pace with age, it's agood recipe for leaks ;o)
My first port of call would be a proper pressure test of the system as it needs to be pressuried to really show where the leak eminates from.
Under the intercoolers and super charger there are the two heater feed and return hoses plus a couple of 'bleed pipes'...the little black plastic ones.
But from what you have shown, it seems like the leak is coming from up front of the engine.
Systimaticly go through all your hoses and check the pump.

 

My latest leak was a weak clamp at small hose from throttlebody to heater hose-octopus t-fitting. Re positioned clamp leak stopped. At first it appeard to be the heater hose leaking.

 

Pressure tester is your best friend.

 

I bought a scope for the sole purpose of doing this. I have this one:
Whistler 9mm Inspection Camera: Automotive : Walmart.com

I am not able to get it down into the area where the heater hoses are. It is all too tight. Have you actually gotten a scope down in there to see that area? How did you fit it through?

I have a stant radiator pressurizer tool but it is older and it don't believe it will hook to the radiator fill cap on the Jag.
Testers & Adapters - CONSUMER PRODUCTS - Stant
Do you know a product that will?

 

I believe i found the adapter i need
Stant 12023 Threaded Radiator Cooling System Tester Adapter

 

Were you able to test this out? I have the same Stant pressure tester and was trying to find which adapter would work. The link you posted mentions "late model Jaguars" but when running the little compatability check app, it says it's not compatible. What did you find?

 

I notice that this page: https://www.carpartkings.com/stant-e...ter-12023.html

says this adapter works with the XJ Jags up to 1997 but doesn't list it for 1998 or newer (mine's a 1999). I guess there was a change in the cooling system in 1998? Or, as mentioned in other threads, do they not show it as being compatible because it doesn't block off the overflow line (which is easily done manually)?

 

I got the pressure tester in and tried to pressurize the system. The adapter screwed on to the reservoir just fine. But when i tried to pressurize the system i could not. At the time i figured it was just because the leak. But i bet it was all going out the coolant overflow like you said. I have my car all in pieces right now and cant test this. So basically all i can tell you is that it did screw on correctly.

 

The adaptor screws on fine but does not block off the expansion over-flow
outlet which is just below cap level.
I prefer to use the expandable bladder type of pressure tester....had one of these for years and has never given any problems in getting a tight seal in a range of different neck types.

 

Do you know the make and model of the expandable bladder tester. I am having difficulty finding one.

 

My wifes '02 XJR had a slow leak coming out of the water pump discharge pipe under the supercharger. The leak was so slow that you couldn't find it while the car was running and hot, because the coolant would evaporate so quickly it never hit the ground. But you had to add coolant every few days.

Well last week her expansion tank cracked open and the car overheated. I too the opportunity to pull the supercharger, replace the o-ring on the bottom of the pipe leading out of the water pump. I also replace the two heater hoses under the supercharger, as well as the vacuum hose for the evap system. (That was melted and was the cause of my system too lean error code.

Anyway now that you have hear the long story, I found the leak using a pressure test kit I got at harbor freight. Cost like 60 bucks but has most of the adapters you could ever need. It works on my 98 explorer both of my kids chevy cars and the XJR. Well worth the money.