Good day my fellow jaguar enthusiast!

I recently bought my first Jaguar and I canīt be happier with it. Unfortunately,
t leaks a lot of coolant, the mechanic said it looks like its the pipe right under the intake manifold that's leaking. When the car is parked in a downhill slope there is a little stream of coolant running from under the front side of the car.
So my question is if anyone here has experienced the same problem or similar? Do I have to take the intake manifold apart to reach the pipe?

Many thanks to you all for your help and time! Cheers!



Even though this is from a X308 i can imagine it would be a similar plastic part that responsible for the leak.

 

Get yourself a Haynes Manual, you'll get all instructions there but you can also see parts diagrams here:

https://parts.jaguarlandroverclassic.../brand/jaguar/

What leaks is either part 3 which is a very well known failure item and called a 'ba$tard' hose or item 17. Ideally, its much easier to replace that hose with intake off but apparently some people succeeded replacing it without removing intake. I've never managed myself and attempted it unsuccessfully twice. If it leaks from under water rail and you have to replace gasket item 17 on the diagram then you might be able to do it from underneath the car but again probably much easier with intake off. When you decide to take the intake off, probably best to replace intake manifold gasket too, its cheap and probably disintegrating now.
Removing intake isn't really difficult or time consuming either.
One thing to remember, if yours is leaking from under water rail and you have to undo it to replace gaskets, be extremely careful with the bolts holding water rail to engine block. They are made of 'carrot cake' material and snap super easy, I'd be heating them up before trying to undo them.

 

Katar , I'm sorry you didn't succeed in your attempts. I did though, and you're right, it's a ba$tard. I removed the air pump to get at it and while I was there I changed them all.
I'm not sure how similar your 88 3.6 is to the 92-94 4.0 but i would definitely remove any bolt-on thats in the way rather than mess with the intake. Just my thinking. I was able to get a kit of all the hoses so I knew going in that I had everything. You can check Sngbarratts or Moss motors for the kit if you want to go that way. Good luck.

 

Hi xj40mgo,

Congratulations on your new-to-you Jaguar, and welcome to the Jaguar Forums!

Personally, I recommend disconnecting the intake manifold and tying it away from the engine. It's not nearly as difficult as it sounds, and with the manifold out of the way, it's far easier to replace the water rail hose (Part 3 in the diagram below), the coolant rail gaskets (Parts 17), and the smaller hoses. You can also easily deal with common oil leak points like the oil filter housing, oil cooler line O-rings, oil filler tube gasket and dipstick tube O-ring, and you can change your oil pressure transducer or switch, or at least remove it and clean the oil off of the threads on the sender and in the port on the engine:



You can download a U.K. edition of the Haynes Manual at this link (it's missing a couple of chapters but is still an incredibly helpful reference):

Haynes Jaguar XJ40 Repair Manual


You can download the wiring schematics here:

Jaguar XJ40 Electrical Guide 1988-1989


Here are a few other helpful documents:

Jaguar XJ40 Technical Introduction 1988

Jaguar XJ40 Model Update 1989

Jaguar XJ40 Power Hydraulic System Manual


Cheers,

Don

 

I'll throw my vote in with removing the manifold. I replaced my hoses by removing the air pump, had the car on a lift so I could access from underneath, and still had a hell of a time. A miserable job! I later removed the manifold for another reason and only then, realized how simple the hose replacement would have been had I just gone that route in the first place.

 

I've replaced several of these hoses on 20 years worth of Jaguar ownership. Removing the intake manifold is a fairly easy job - less than an hour.
Try to break the four #2 screws loose. ANY SLIGHT resistance stop and get a small torch and apply heat. The gaskets (17) leak corroding the screws (aluminum oxide)
the only thing that breaks aluminum oxide is heat. The screws are an 8mm1.25 X 25 thread (?) that you can purchase in any auto parts store. So, replace the hose, gaskets, screws, never seize the screws, new intake manifold gasket and you are good for many years and many miles.

 

I'll third the manifold plan. Mine had a leak at the gasket on the block so the manifold had to come off. It's not that hard and while I was there I just replace every hose on the car. Its worth the time and it makes the job less stressful.