Hi Guys,

Want to get some feedback on the following as I'm sorting through my newly acquired 2004 XJR - 97K miles.

Regarding cooling. Reservoir is full.

I run the car, normal temp range (a tick underneath 1/2 on idiot gauge) good heat from HVAC but I need to hook up my VCM to see real time temps.

Upper hose feels soft, like no pressure. Checked oil - good, no coolant.

About 5 minutes after shutting the car off I notice coolant dripping down the front center of the engine block and drips off the front center bolt of the oil pan. (in the area right behind where the oil filter is) and it drips and leaks for a while.

I thought the supercharger cooling pump wasn't working but I confirmed it is.

No serious loss of coolant in reservoir though despite the leaking?

On my 04 XJ8 I noticed a "flow" in the reservoir when the engine was running. Not sure if that was norm or not but never had coolant leaks with that car.

I've been told the XJR's are notorious for water pump failure but it's so hard to see the water pump without taking a bunch of stuff out. This is what I'm leaning towards or the infamous under the intake hose...

I know that will be a PITA but hey... I changed tensioners/guides/chains on my 4.0 - I can't imagine it being harder than that.

Any feedback/thoughts would be greatly appreciated!

Thanks in advance.

 

Everything I have read in this forum about a leaking valley hose indicates coolant dripping at the rear of the engine.

I have replaced my valley hose but it was in ok shape at 99k miles.

It could be the water pump but it could also be a pin hole leak in any one of several hoses behind the radiator.

I had a pin hole leak where the coolant sprayed back on the engine from one of the hoses and was very difficult to find.

I found it by taking off the upper plastic shield over the radiator and shining a light at different angles thru the hoses while the engine was running.

I ended up replacing all the hoses and water pump, thermostat.

 

Barrs leaks?

 

never in any of my vehicles. Snake oil...

 

Can you get a borescope (USB camera with light) and look for coolant stains?

 

I tried but the monitor battery ran out of juice. Going to try again tomorrow. It's like trying to look into the Abyss...lol

 

I think it might be a bearing seal on the water pump. When you get your scope working again, see if coolant is seeping from the weep hole on the underside of the water pump. You may have to take the pulley off, which is no small task.

You might be able to tell if the inside of the pulley is wet without taking the pulley off.

 

Went into my darkened garage with my flashlight and scope tonight. Drivers side of the pump is moist/wet and I could see crusty dried coolant right near the gasket (looks like paper gasket) and looking from the passenger side looks like there's some coolant in the area right behind the pump.

Base of thermostat housing looks dry.

I'm going with the water pump.

I have a new OEM water pump on the way.

 

Just to follow up it was the water pump. Additionally, whoever owned this car before me should be shot for stupidly over tightening the bolts.

One rounded off, bolt extractor = fail, trying to get a 7mm 12 point on = fail. Wound up cutting the bolt head off with my dremel (yea, in that super tight area - luckily it was one of the top bolts) filing down and pulling the pump off.

With all the heat from the cutting wheel I was able to twist what was left of the bolt by hand.

What was left of the bolt is in the lower part of the pic.

New OEM pump purchased from a fellow member will be installed once replacement bolt arrives.

Spec - 8Nm + 90 deg.

 

Nice diagnosis and repair.

 

Thank you sir. Just when I thought I was done with Jaguars they drew me back in...lol

 

I have three different torque wrenches. One for heavy duty stuff like bushing bolts, one medium duty, and one for the small things such as water pump bolts.

 

From your pic, it was only the seal that was damaged and caused the leak?
Is the pump itself still in good order or was it better replacing it altogether once dismantled?

 

The failure that I had on my X308 was the internal seal allowing coolant through the inside bearing and out the weep hole. Both the 4.0 and 4.2 use the same water pump.

does the new pump have an aluminum impeller? If not, check some of the archived thread. The earlier pumps with the plastic impeller were prone to overheating problems and leaks.

 

The replacement pump I have is Jaguar genuine OEM water pump with plastic impeller and updated housing not requiring any o rings. Just a metal crush gasket.

The old pump itself looked good (no broken impellers but clearly has been leaking from the main seal through the o ring and the drivers side outlet was compromised as well) but it's best insurance to replace the water pump.

 

Update... This is resolved!

As indicated, the water pump was the main leak issue. Car is quiet now and hoses are pressurized upon vehicle being warm. Followed JTIS bleed procedure, no issues.

Changed both drive and SC belts while I was in there.

I also changed out hose #27 in cooling system diagram as when I was inspecting hoses that large 90 degree hose felt brittle and very weak vs. new replacement. I suspect this hose was leaking also.

Now off to repositioning PS return hose clamp as it's weeping. Found it now that the coolant issue is sorted.