Going back on topic, I found the culprit.
followed the wife to drop off our workhorse suv for her timing belt/water pump combo and test her out.

Parked to wait and thought, eh, I’ll open the bonnet and take a look.
Yep, coolant. Maybe a tablespoon.
( See pic below )
It’s the top nipple now near the bleed screw.

Wiggled it a bit and noticed when I push down on top, there is a small stead stream coming out.
( Attempted to attach a video )

She never went above 201F in a 20m round trip with a lot of idling. Thank goodness.

fun times.

 

that is where mine cracked also, NA not SC but...
as to you temps, in Hot Texas mine are similar to your posted ones except in the summer I can see 220 in heavy traffic with an ambient of 110(f). It does quickly drop once moving but it is scary. I investigated and it is within the operating range Jag states...CeeJays waterless coolant looks better and better to me.

as to the coolant exchange, I bought and used this Harbor Freight unit, https://www.harborfreight.com/coolin...kit-64985.html

wj

 

Been considering picking one up, but I'd have to know what I'm doing also lol.
So seems as long as I keep an eye on coolant levels, and put a smidge in there after every drive (and cool off), I'm good until she gets in the shop.
I found the hose online just in case. Not too bad. I mean crazy for a piece of rubber, but not terrible by Jag standards.

I also did some studying. Earlier I was concerned about touching the SC. Removing the drain plug and having to replace the washer.
But I discovered, unless what I read was wrong, it is a totally separate closed loop system with it's own pump.
So am I wrong to think that the expansion tank is unrelated as that is the issue and can just replace the tank and burp the main engine coolant system?
Much easier task that I may feel comfortable doing.

 

Looks like I’ll just have the shop do it. Only charging 30mins of labor.


Doing the mounts anyway. But almost $200 for a flush and fill? Ouch.

 

$25 per gallon for prediluted antifreeze also seems incredibly high priced.

 

Yeah, tempted to bring my own, lol.

But I did find out that is normal for the coolant flush.
Just picked up the old pilot from a diff shop after getting the timing belt and water pump done.
Before I walked out I said “I know it varies, but what’s the range for a coolant flush/fill?”
He said $150-250.

 

No coolant issues with Jags are fun....Good luck with your fix.

 

why bother with a flush and just perform a drain and fill?

 

Isn’t that standard?

 

I have heard of people getting flushes and then something somewhere in the system gets loose and causes a problem. Not often, but it has happened. Many decades ago I'd gravity drain cooling systems and then use a garden hose to flush, letting all the leftover coolant go wherever the stream of water took it. Quick and easy cheap way to do it, but then environmental concerns became a reason to not do that.

 

Sometimes... just because other people do it does not mean its the right thing to do...
The workshop manual only lists the instructions for ""Cooling System Draining, Filling and Bleeding"
There is no "flush" involved. (Incidentally, ditto for the transmission, per ZF instructions, power steering, diff...)
None of my well used vehicles have ever needed a flush. I accept I change the fluids more frequently than most.
Cheers!

 

I will ensure that their line item for coolant replacement does not involve anything outside of the activities needed to remove main engine coolant and fill main engine coolant. 😬