So as you know, had a cracked nipple in the overflow reservoir.
Just had that replaced and the coolant drained/refilled and they "flushed" the radiator.
Drove her home, popped the bonnet and let her sit.
After things cooled, I removed the cap and the coolant is below the internal "max" line. So I top it off.
Leave the cap off the reservoir overnight. Next morning, it is a cm below the max line again.
No signs from above of leaking. No drips anywhere.
Top her off once more. Leave it sitting overnight with cap off.
Today, down a cm again.
Grab a flashlight and lay on the garage floor.
The front engine cover is wet. Ugh.
So I remove the 5,496 screws (why???) and get the cover off.
No puddle, but def wet underneath.

There is a small additional cover under the radiator.
Two screws in the front, but can't tell how it is attached along the longer rear line. So I leave it.
There is a grey spongy thing on top (where I can't see) that is poking out the sides and one side is wet.

Engine top and under cover are off. Searched every inch from top and bottom view.
No trail of tears. No drippings. couple of small droplets on the underside fan housing, but nowhere near enough to get the under pan as wet as it was.

So have two trains of thought going on.
1) Could the mess on the engine under cover be from the "flush" and they just didn't clean it?
2) Could flushing a radiator old enough to vote cause problems which would result in my reservoir level dropping a cm overnight?

I called them and they said best thing to do is bring it in for a smoke test.
But while I have that annoying to remove cover off, I'd like to see what you guys think before I put it back. (I cleaned it)

Adding pics:

 

If the level in the expansion tank keeps dropping that quickly, I'm sure that there must be a leak somewhere. If you use a torch to look down into the V and at the top of the bellhousing. If there is any pink, I would suspect the valley hose. However, it looks as if the leak is further towards the front of the car so the water pump is a likely candidate.

Richard

 

If it makes you feel better (?), the day after I finished my valley hose replacement I had a new puddle under the car. The water pump had failed. Blessedly, the water pump is an easy replacement on the 4.2.
Best of luck finding and repairing your leak!

 

Spent 20 minutes with a torch looking in every square inch of the top, every space I could look down, both sides.
No signs of leaking anything. Trying to figure out where specifically the water pump is so I can look at it.
Did a forum search. Tons of pics of the pump, removed. Most on a NA not SC.
I'll keep poking around.


Update. I think I found the pump. Black in front with 3 bolts. Was a struggle but reached in and looked/felt around. She is very tightly in there and no leaks.

Pic for refefence. Man it would be great if someone took this and labelled everything.

 

Put your bonnet in the service position and you can lean in to see the WP pulley. Held on by 3 bolts.

Once that's off, you will see the 5 bolts holding the WP on. Those are the ones with the 8mm head. You don't remove the two 10mm bolts.

It really is super-easy to replace.

 

You can buy a cheap pressure testing kit which will pressurise the cooling system and then, with all the undertrays off, you will surely see where the coolant is running down once it is under pressure if it's not obvious when it's not pressurised.

Richard

 

Auto parts stores lend them out at no cost. - well deposit fully refunded upon return.

 

I can verify, that even with a pressure testing kit, (which I own with the proper fitting adaptor for the reservoir) not all leaks are evident or can be found with the kit. The kit is usually used when the car and coolant is cold. Some leaks are found when the car has been driven and warmed up. While the kit may be helpful, there are so many variables for our cars with so many plastic lines and connectors, it's not always an easy to find.

 

Thanks.
For now I cleaned up the under engine cover (rear smaller one was clean).
I’m hoping it is just that the shop didn’t fully burp the system and leaving the cap off for a couple days allowed air to bleed out.
Level hasn’t changed, will check in the morning.
If it drops again, I’ll do the burp process.

I’ll be driving her about 20m x2 (round trip) tomorrow for a dinner with some friends post quail hollow tournament. Always keep a jug and funnel in the spare tire space.

 

That is annoying. Been there, done that.
As I have mentioned before, "a flush" is not a standard jaguar methodology unless the coolant change interval was not followed. Just drain and fill. Of course, in days gone by, there would have been deposits that were flushed out. Highly irregular now.
Also, that is a wet mess. And as you are losing a cm a day, That is concerning as the you let the engine come to room temperature.

I'd be hopeful the shop wouldn't leave a mess like that. Actually, I would have cleaned the whole engine bay.

My apologies @Circumnavigator , I don't recall if your car is supercharged. If so, the supercharger coolant path is higher than the reservoir. If you have an air pocket in there...

Button it all up tight and go for a drive. When the engine is hot, raise the bonnet and give it a whiff??

 

Yes. 2008 XKR Portfolio convertible.

Seems like there were small black bits in the coolant on top of the under engine cover when I cleaned it.
Not a ton. Few bits. Very small. Could be from anything.
My understanding was that the supercharger cooling was a closed loop system. Not sharing coolant with the engine cooling system.
But could be mistaken.
Supercharger was fully serviced a few years ago I believe by the previous owner. So I didn’t have them touch it.

I did button it up. Let it drop to low idle and warm up a bit in the garage.
Gave it a few gentle revs.
Checked coolant, all good. No loss.

Giving it a wash before picking up the brother in law from the golf tourney tmr and heading to dinner.
I’ll get back to checking it before starting it each time.

For the moment the garage smells like cherry bomb degreaser from cleaning the underside covers. Don’t think I can smell coolant over that.

 

The reason I provided the docs... you MUST confirm no air lock in the supercharger.
The pressure method of filling is through the supercharger. The pour method, explains the need to vent at the supercharger, then top up at the supercharger.

 

Yep I looked through them. Thank you for that.

Just to avoid misinterpretation from them to me to the forums, here is what they said in an email prior to the work:
”Coolant is drained and refilled, and fluid is flushed through the radiator & heater core. They are referring to a "power flush" which can damage plastic components.

The supercharger is lubricated with oil, not coolant. There is an auxiliary water pump that uses antifreeze to cool, but not lubricate. The cooling system will be properly filled and bled.”

I will continue to monitor. Just checked the level after sitting overnight with cap on and no change.
Just removed the cap. Will let sit all day as I go strawberry picking with the daughters.
If the level has not changed by tonight and I see and smell no signs leaking coolant, I’ll drive it this evening for the dinner plans.
Then I’ll check again. Continue to drive and monitor levels and operating temp.

 

Where I am still confused is that any and all internet searches, AI inquiries (across 3 GenAI tools) say the SC cooling system is closed loop.
One even mentioned an “intercooler/supercharger coolant reservoir” and then tried to tell me where it is.
But a search on that only brings up the same expansion tank.

So, the question from this still newbie is:
Does the same coolant that runs through the engine also run through the SC system to cool the incoming compressed air?

 

Well... being that AI has so much more practical experience over the techs that designed and use the manual...

Truly, I'm not certain why you're spending so much effort discounting the good process that has been in place for 25 years.
Then again, I don't understand the "battery is done" naysayers, either... The very folks that need to keep the car on the maintainer.

 

Not poopooing anything. Looked at all three docs. I consult AI and point it here just to see what it says.
what is said here is always ranked highest.

Right now I’m in an “if it ain’t broke, don’t mess with it” mindset.
The SC had its big service. That would have included the coolant as it comes apart. It has not been an issue. So I don’t think it became an issue since it wasn’t touched. So not touching it.

None of the coolant (wet, not puddles) was near where it would come from the SC/engine. It was all way up front under the radiator and streaks blown back a bit.

Best course at least for now seems to be to monitor it.
Part of that will be driving it, which I haven’t had a chance to do yet, but will do this afternoon. Then check for any drips and monitor again.

If I find no more coolant anywhere and the level hasn’t dropped, I’ll attribute the couple of small level drops to leaving the cap off and some air in the system bubbling up. But still monitor diligently.

Just checked after the cap being off for about 6hrs and the level hasn’t changed.