I just love the KV6 in my launch car. Nice sound, revs quite nicely...and I hate it at the same time, probably as much. Some of its design is just so poor...especially on the coolant side. Having the stat sitting in the V is just one example. But the whole cooling system is, as we all know, something to give worries to all KV6 owners. Air locks, blocked heater matrix, an expansion tank where the min/max levels can only be seen with a flashlight...and running temps that can not accurately be determined from the gauge.
Here's another one for you : did you know that MGR did design an 82° stat, with a different part number, that was provided as warranty kits to dealerships, together with an improved resistor for the two-speed fan?
It was designed to have the car run a bit cooler than on the standard stat (which opens at 88°), and was to be fitted to cars that had already had temp issues, including broken fans. Initially it would not be fitted separately of the new fan resistor.
This different stat is part nr. PEM100860 (the original stat is PEM101050). Try looking for PEM100860, you won't find it anywhere, its part nr. is not even referenced with XPart.
Turns out my launch car was fitted with this 82° stat when the belts were done in 2009. Even though the bill mentions the standard one (PEM101050). Of course it would : PEM100860 doesn't officially exist.
Ever since I've owned the car it's been running at 96° on idle roads, and while stationery with the slow-speed fan being on, has always struggled to go below 96° where the slow-speed fan would cut out. So while I had the belts done again a month ago, I asked my mechanic to change the stat, not knowing it was an 82° one, because I thought it was a bit sticky and I wanted the running temp to be what it's supposed to be ideally : 2 or 3 degrees less. He advised against it, saying the stat was perfectly fine from the outside, but upon my insisting, did it anyway.
He fitted me with another 82° stat, which he had in stock. Worse results : car was now running around 98-99 all the time. While stationary, would not go below 100°. I talked about this here :
http://www.the75andztclub.co.uk/foru...d.php?t=236944
So this 82° stat is definitely opening up later than what my original one did.
So today I collected my car after he refitted the older 82° stat, the one originally fitted in 2009, which was still fine.
I'm now back to the original temps...the ones I've been having since I own the car.
But it makes me wonder what the results would be if my car were to be fitted with a standard 88° stat.
I did a test-drive of another KV6 automatic last week, a Tourer with only 18.000 kms. It had a brand new stat fitted last month (the regular one). Reading the real temp on the IPK while driving, it was between 95 and 98° at all times. Go wonder...
And we all know now why the needle won't bulge between 75° and 115° : MGR was not capable of having a coolant system reliable enough. They designed an 82° stat which they did not even think worthy enough to reference as an aftermarket part. They only waited for cars to overheat to fit those 82° stats to cars that had already been "weakened" so they would tentatively not run as hot as they used to. And this is all because they knew, down in their guts, that their coolant design could have been way better from the start...