V12 cooling system maintaining
 

Seeing many threads about engine temps etc.

So, I wrote this paper on what I have done, and still do, to get this area back to spec as best as possible.

I will ask GGG to "sticky" it for ease of access.

Thank you for such an informative PDF.
Being someone that has become an owner of XJS V12 which has been a dream of mine since they were new even with all the talk of how expensive they are to own; your straight talk of that they are a well engineered car and engine that had a 21 year run, that says a lot to me.
Maintenance is the key what keeps a car going the way it was designed, I plan on following your well thought out ideas on getting a car that is 30 years old back to enjoyable driving, working and dependable car, which is what Jaguar are known for.
I knew this adventure was froth with bad and good things but having someone who has been thru those good and bad things makes me hve a better out look for which I can't thank you enough.
I wish I as Down Under to share a few drafts with a fellow that seems to enjoy things in life!
Well done sir! I will enjoy reading more from you and the other enthusiasts on this forum hopefully I will help someone in the future.
Cheers from Pat the Poppa (trying) to do it

Awesome Grant, many thanks, I've been chasing an airlock on my 85 XJS and this helps heaps :)

Cheers . . . Mike

fabulous detailed write up, I'm glad I found it as my replacement hose kit just came in the mail and this project is definitely in the queue.

Just checked my thermostats. Waxstat 82C.
I measure them to be 41.5mm open, ie a bit short, but not 39mm short.
There is no signs of contact between disc and seat, so they still must be too short.
My question: Is it possible to source good thermostats from inside EU, or will I have to buy from Australia ?
I will place an order from SNG Barrett soon. Any experience with the thermostats they offer ? https://cimg6.ibsrv.net/gimg/www.jag...0dff7239c.jpeg

I thought 41mm was the magic number?

Didn't someone here post something about adding a rubber washer to the rear disc of the thermo to ensure contact with the seat?

Cheers
DD

Doug,

I looked at that way back, and finding an adhesive to "live" in there was the problem. OK, lots of thoughts/suggestions etc, then I found those stats, and went that way. My main concern was if that "added" item came adrift, what would happen??, did not like that thought path.

Leo,

That stat spec fits many vehicles. Its 1AM here and I need some sleep. I will search out other vehicles tomorrow for your area.

41mm is the "magic" number. One of my PreHE was closer to 42mm, so factory casting/machining tolerances maybe at play.

Leo,

Here you go, attached.

The page from Dayco Aust Catalogue listing the cars that this stat fits for the Aust market.

Many of these cars, and/or variations of them, would be in your market.

First Euro-alternative bought and measured: PSA (Citroën and Peugeot) 2.0 HDI uses a 83°C thermostat, with correct diameter and a promising initial length 1,5-2mm more than the Waxstat, but it has very short travel and ends up at 39mm open.

Leo

BUGGA.

Leo, and others that have issues finding Dayco, Tridon, or Parts Suppliers too lazy to convert for you,

This has bugged me since this morning, and with 55 years in the Auto Parts Industry, there must be an alternative, its simply what we old school Parts Guys do.

Gates 33188, SAAB etc, as per that list I posted in #8 above is what you need.
Same specs as the Dayco DT18A.
The ONLY thing I dont know, and their crappy website does not specify, is the opening length, so I am ASSUMING the same @ 8mm, as other stats.

?Bay has them all over for $13.

Found a Mahle thermostat locally for SAAB and Volvo engines, and it’s too short. Should be same as the the Gates 33188 as I see it

31 closed, 39 open.

https://cimg0.ibsrv.net/gimg/www.jag...6e58d8aa3.jpeg

Dunno, Gates specified 35mm closed on that via their website.

So, as I suspected, the 8mm opening stroke appears to be an industry standard of sorts.

I will go looking again, as I said, their website for specs is terrible, compared to what I am used to.

My next step will be ordering the Gates from eBay. It was just too tempting with the Mahle available next door

Leo.

Just spent the last 30 odd minutes on the Gates website. oh dear, am I glad we never had Gates at work, as their catalogue is terrible.

I tried "dimension search", only allows for hoses, belts and pullies, bugga.

Looked at Jaguar V12, and their listing is the 31mm stat that we know is too short.

Ford USA, AKA Mustang 4.6ltr = TH00791G1.
I cannot decipher their numbering system, but "91" is more than likely the temp, and we want 82, but substituting the 91 for 82, goes nowhere, so that tells me their number system does not follow any normal logic, bugga again.

Manners in the UK should have them, and I would simply ask them to measure "disc to disc" prior to purchasing/ending, and if it come out at 35mm or 36mm, good to go.

Clearly we be blessed for Auto Parts downunder.

Hi Grant, quick question if you don't mind. You recommend flushing the block with a garden hose. That will obviously get old coolant out, but won't it just replace it with water? And not distilled water either. Is there a way to go about this that easily drains the whole block? Right now everything is disconnected, but there's still visible coolant in the block.
Thanks, Gareth

Gareth,

Questions are good, especially at my age.

I pondered that for about 2 beers waaaaay back then, and decided that tap water would be better by a country mile than old stale God knows what coolant/mud/dissolved head gasket etc etc.

With the water pump off, the remaining water is near zero, but it will never be "DRY" in the true meaning of that word.

I used Concentrate and mixed my own., 20ltr at a time, and then when I had to top up after the bleeding, I used Concentrate to a MAX of 1ltr. Compared to that AWFUL SQ36 rubbish Jaguar/Leyland used at the factory, then the mandatory can of BarsLeaks, any countries tap water would cause less issues.

Like everything I do, I never overthink what I am doing, the car will be happy, maybe happier, with what I am doing, so move on Grant.

The corrosion I found in any of the Jag engines was ZERO, even the really sad neglected PreHE that had liquid mud in it.

Biggest issue with the V12 is the "Open Deck" design, which allows the liquid to slowly dissolve the exposed head gasket, NO big deal, the external perimeter and the cylinder "fire rings" are NOT affected, so coolant loss in zero, just that horrible build up of "muddy goo" around 4/5/6 cylinders on both sides.
My 85 HE had 2KG of that stuff scraped out when the engine, when it was out of the car, and the heads off for oil leaks and other things. I dropped a nut down the plug hole, and could NOT get it out, so apart she came, bugga.
That PreHE is now at 654000kms, and still thundering, and I am NOT touching that engine, it runs, and runs well, leave it alone. A few oil leaks, stops the rust underneath, HA.

I just changed the coolant and checked my thermostats length and function. Before removing the thermostats I blew gently into the bypass filler using compressed air, and that pushed out several liters of coolant. It might not make a difference if the pump is of, but during a coolant change it will push out more coolant.

Electric fans
 

Hi Grant, you mentioned in your notes that you used electric fan pack from Ford, which fits without mods.
Can i know which car's fan packs did you use?
My google mostly returned fan pack for Falcons..
Thanks

And also i managed to purchase the Tridon TT228-180 from Sparesbox Australia of anyone is interested to know
https://www.sparesbox.com.au/part/tridon-thermostat-tt228-180

Google be spot on.

I did NOT mention Falcon, as some markets (USA mainly) have a different Falcon to us, and confusion is never good.

I used the EF Falcon Taxi Pack fan assembly. Made by Bosch Germany. No Longer Available.
The Chinese knock offs, are worse than useless.

BUT
You are a Jag V12 owner now, so you must learn:
Alcohol consumption
Sense of humour
Ability to think WAY outside the box.
etc etc.

A member from Scotland, and I forget when and whom, fitted the fan pack from the X Type Jaguar. Mentioned it basically fell in, and worked well.
Others have used the X300 fan pack, a little too wide I would have thought, but if its been done, its been done.

Wrecking yards, not sure of Singapore having them, THEY MUST HAVE, is a good place to look around.

Hyundai have awesome fan packs, as do Toyota etc etc, and imagination (outside that box) is all you need.