Hello, I Have a new coolant leak that is leaking from the back of the engine. It drips down between the engine and transmission. I have read that some people have found it to be a "valley pipe". I have replaced the heater valve, water pump, and thermostat. I attached a photo of where the coolant is leaking. If it is the "valley pipe," am I looking at a huge job? It is a 4.2 NON-superchaged.

 

The valley pipe is not the same on the naturally aspirated engine as the supercharged.

This is because the throttle body is at the front of a naturally aspirated engine, whereas the supercharged it is at the rear.

On the supercharged cars a hose runs from the front of the engine to the back, in the valley, hence the name.



There is a hose on the N/A that goes from the same point at the front to the throttle body, but it's shorter.

On the S/C cars it leaks at the front of the engine, but you only see the coolant coming out at the rear, as it makes it's way down the valley.

Could be a similar issue with a N/A 4.2, although I don't recall anyone reporting the issue.

 

Access simply to look may be rather better on the NA. Let us know!

 

I put a coolant pressure tester on the coolant tank. After pressurizing, I saw a stream coming from the pipe right behind the thermostat. There was a hairline crack in the plastic. I am going to see if I can get the part from the dealer tomorrow. Does anyone know what this piece is called?

Thanks Kelby

 

In JTIS it is called Engine Coolant Inlet (item 11):


(click on the image to enlarge it)

In JEPC (Jaguar Electronic Parts Catalogue), it is shown as part of the Thermostat and Water Outlet Pipe (see bottom right of the diagram):


(click on the image to enlarge it)

Unfortunately the plastic section you need does not appear to be available as a separate item.

Graham

 

Replace the entire assembly. It's all plastic which tends to get brittle, warp or crack, and then leak as the years and heat cycles go by. I had to do this job on my wife's 2006 XK8 back in November. Only the thermostat housing was leaking, but fellow forum members and my research confirmed that replacing just that one failed plastic piece would inevitably lead to more leaks if I left the rest of the original plastic coolant pipe pieces in place. So I worked a discount on the entire assembly from my local dealership parts department and replaced the whole coolant outlet duct. It was an extra $40 or so to do it all. Well worth the money, time, and effort since I don't expect to have to do this repair on her car again....

 

that is only avail with the T stat housing. And I no longer just replace the the housings on 4.2's but the hose under the intake as well. Youre half way there and due to age it is not wise to let it go and not do it at the same time.

 

Greetings!

I am hoping to get some assistance once again. I’ve been away for a while When I was looking to address my cat running slightly higher than “normal temp”, then to the temp gauge going past the half point mark.

The 1st Leak
This first leak was fairly easy to find, it was cracked expansion tank. Things were good for a few weeks then...another leak started...

The 2nd Leak
This leak was also fairly easy to identify, as the forum insight was spot on— it pinpointed the water pump. So, as advised, I also swapped the thermostat as well. Let me point out that, prior to these replacements, both my AC & Heat were not working, but at the time, I thought that I could address that at a later time (based on what i am now reading, I am hoping that was not a futile decision.) So, once again things were good for a while perhaps a month or two, them the Temp gauge started climbing to a hair before the mid point marker (if you’ve had similar issues- I think you can relate the the PTSD that comes from that gauge moving anywhere past “normal” temp.) Anyway, it was time to address the DCCV.

DCCV Replacement
From reading and scouring through posts, I learned that a faulty (stuck-shut) DCCV could contribute to other issues aside from AC/heating. So, upon replacing, we discovered that the control valve connector had not been plugged in (how long, I don’t know). But, we changed it, tested the heat and air— heat worked AC did not. This is where I am. I bought the AC refill, I have yet to add it. In the meantime, car seems fine...but then...

Odd noise from Passenger Side
After relaxing the DCCV the car seemed to be okay, the temp was fine for about a month. Then one day I noticed an odd sound while driving on the highway. My windows were down and it sounded like fast “fluttering.” At first, I though it was the car next to me and again me being keen and knowing the sounds ans smells of my car, I fell back to see if indeed it was the other car. No, it was mine, I thought perhaps it was a plastic bag that got caught under my passenger wheel (or somewhere close). I stopped at a station, investigated and nothing. But then, when I started to drive off, as soon as I started to accelerate around (with less noise/traffic around) the sound was back and I realized it was more like a soft-windy “sputtering” kind of like a Cessa and I could smell fuel, but, didn’t think anything of that because I was at a gas station after all. Regardless, I panicked, went straight home. When I got home I immediately popped the hood and could not find anything. So, I drove the car very short distances for a few days the car temp started to climb and again I panicked because a new leak sprung. Again, I panicked went hime and this is where I am. So now I am dealing worh 2 things the sputter and the leak. Let me save time and say that the sputter turned out to be the
a broken “Exhaust Recirculation Tube” which I have since sourced (took a while since they are no longer making them) but halt I found one in excellent condition. However, I still have the leak to identify.

Note: I am hoping to identify the leak so that I can fix it at the same time as the tube.

3rd Leak (Co-current issue)
As mentioned, the temp started to climb (face-palm), this time the gauge well past miS point, but never reached the red or close to it. But, this leak APPEARS to be coming from seems the center behind the engine. Being the earnestly curious-nosy and determined researcher, I began to look around. I could not get under the Car, but when I pooped my hood (standing in front of the car facing back) I noticed there was some type of fluid spatter aiming towards the back-right side that got on the power steering tank. I watched the Dexter series, from that i learned to look towards the source. So I follow the trail and it leads my towards the front of the car. As such, I suspect it’s the radiator hose because I see some coolant in that area. I call my mechanic, he comes and confirms that I need a new radiator hose. He did not have time to investigate leak and now he is out of town for a while. So I am hoping to get help here!

MY CONUNDRUM: what about the leak towards the back of the car?

I am desperately hoping to get some assistance because I refuse to give on my gal. She’s only has 150k miles, is still beautiful and has a lot of life left o her! Plus, it is the car that my daughter came home feom the hospital in, so I have always planned to give it to her when she gets her license in a year or so. Okay, sorry, back to the leak. As mentioned thai fluid comes out fast and it does not look like the typical coolant fluid that leaks from water pump. It’s more watery. From what I have been reading, it’s possible that it is the coolant lines behind the engine “Valley Line/tube/housing” (can’t quite recalm exact name) or the plastic bits that get brittle and break- but I think it was for the 4.0 or supercharged models. I have not been able to find anything specific for my Style 3.0 and this leak (other than leaks I’ve already addressed). I do t have the part names that go bad, which can also potentially help me research and trouble shoot better. Any assistance will be TRULY and most definitely appreciated!

With Infinite Hope,

Dawn

 

Hiya Dawn,

Your daughter is very lucky to have a Jaguar waiting for her. When I was her age, my folks gave me luggage as a present...

As far as the coolant leak, it's kinda difficult to pinpoint from 1000 miles away. Rather than hazard a guess, I'd strongly and most emphatically suggest you beg, borrow, or steal a cooling system pressure tester. In looks like a bicycle pump and has a special fitting that connects in place of the reservoir cap.

Such a tester is just what the doctor ordered to find leaks. Just watching at idle, you'd easily miss all but the largest leaks. The system barely has any pressure at idle, plus you've got moving parts in the way. But pump up the system manually with the engine off and you can safely inspect everything. It's like night and day.

Some auto parts stores have free loaner tools, too.

One minor gotcha to consider. If the leak is high up on the engine, above the resting coolant level, only air will escape. You'd still know you have a leak as the pressure would decay. I've found such leaks by spraying soapy water and looking for bubbles, but it's rare I've had to do that.

 

+1 on Karl's recommendation on using a pressure tester.

Do not rely on the instrument cluster gauge to tell you the accurate coolant system temperature as the PCM uses a different method to measure temperature of the cylinder head instead of coolant temperature. Use a smart phone with the Torque app to read the engine temperature through the OBD port with a Bluetooth interface.

A common failure point is the 'turret' on the upper radiator hose used to bleed air from the system when refilling after a hose or component replacement. Air is also difficult to get out of the throttle body when bleeding the system.

Your leak can also be the 'Y' shaped pipe at the front top of the engine block as the o-rings eventually begin to seep or leak. The pressure tester can help you locate where the leaks are.

After a cold-soak, preferably overnight, pressurise the system to 1 bar and watch the gauge for changes. If the system begins to drop below 1 bar, search for the leak(s).