After reading virtually all the threads and posts on this topic I am still confused and have questions. Any help /clarification is greatly appreciated as I get "Black Jack" my 2003 XJR ready for its long indoor winter storage .

On supercharged models ( like my 2003 XJR) the manual says that it holds more coolant than the normally aspirated 4.0L engine. Normal capacity is 10.5 quarts while SC capacity is 12.7 quarts.
This is due to more coolant being in the Eaton supercharger itself. So this alters the 50/50 equation such that 6.5 quarts of undiluted coolant vs 5 quarts in a normally aspirated car is required.

The Jaguar manual's drain/flush/ refill procedure for cars with SC is quite confusing and describes removing the very large threaded "bolt" ( for lack of a better word) on the top of the SC. It makes a really confusing statement about avoiding getting air in the system when this "bolt" is removed. Anyone out there have experience with this procedure from the manual ? How to's? Please post.

Also, can anyone describe the correct method to "back flush" the heater cores ? I'm going to do the drain -fill ( with distilled water)-drive procedure at least 3 times before the last fill with undiluted coolant which brings me to the last and MOST IMPORTANT question.........I've studied these threads for the answer to the following simple questions and am still confused.. Clarification Please !

Is Orange Dex-Cool OK to use instead of Jaguar part # JLM209723 (5 liter jar) ? Yes or No?....
and are there ANY concerns with Dex Cool damaging any gaskets in the cooling system ? ....replies greatly appreciated

Ron Simmons
Boston Ma

 

Ron, generally a minimum 50% coolant mix is fine, but running 100% is up to you, after a coolant flush I put 5L of coolant in and 5L of distilled and check on a coolant mix meter, the glass type with a float. adjust as required with more coolant.

As for the flush I've used a product from Holts but you should find something similar, add to water and drive 50 miles, dont worry about back flushing unless you have a major blockage I wouldn't recommend doing it - the coolant loop for the heating system will thank you, just let the flush do its job. I would think 3 cycles of rinsing is overkill when one will do the job...

When it comes to the intercooler vent (the big nut) find a bolt head big enough to fit snug, and tighten 2 nuts on the bolt - this is then the tool to use to crack it open.

When you fill the car a few points, heater on full max heat, (the aux heater pump and intercooler pumps will help move the water round with ignition on) when you start to get a vacuum on the radiator top hose start burping, this forces air out of the system. Start the car when the header tank is full and pour coolant in as needed, again burp if required. This way you almost never get air trapped in the intercoolers and don't need to vent them as their pump fills them for you, a sure way of knowing is both sides cold to the touch as the car idles on initial startup. With the right bolt and nuts it's no problem to let any air trapped out anyway.
The orange/red stuff is the one to use, green is not, if mixed they gel.

 

I tried the 'flush' to clean the engine and get the core open, but it did not work.
I guess due to the tropical weather, the heater was hardly or maybe never used by the PO.

Anyway, I also had read each and every thread, but after studying the hose layout, went the simple way.

With the coolant system open and emptied, all I did was remove the core outlet hose on the auxiliary heater pump (that one is relative easy to reach).
I then put the hose of a hand airpump (those ones most people have to pump up air mattresses for camping) inside that hose, and gave it a decent blow.
Heard a big burp in the expansion tank, and that was it.

Flushed all the stuff out (radiator open, filling water from top), filled her up, and it works super ever since, super hot!
Once a month, even in full summer, I just try to open the heater for a couple of minutes to flush things through, just to prevent build-up.

 

Could someone explain / share the procedure for flushing & filling for the supercharged cars?
I do understand the "normal" flush procedure. Just not sure what I should do with the SC.
Thanks

 

Its the same as a normal change except you have more fluid for the inter-coolers. The plug on top of the SC discharge will help you drain the fluid when removed so you don't get a vacuum drain chug. It also helps to top off after initial fill-up then use the reservoir tank to complete the task after the thermostat has opened for a cycle and allowed fluid into the block. Usually after a 10-15 minute idle or drive down the road and back.
I believe you'll find a 5/8 spark plug socket back end will fit into that plug for removal.

 

One important point regarding the SC cooling system: whenever the charge cooler plug is to be opened (for filling, topping-up or checking the level), the expansion tank cap has to be on and tightened. Otherwise, the coolant from the charge coolers will flow into the expansion tank and overfill/overflow it.

 

Thanks Highorse & Stojanovic!
I am giving it a go today.

 

I am planning to drain the whole system. Reason is that I dont know what coolant is currently in there (might be various types mixed).
I found this post explaining how to do a full drain/flush:
https://www.jaguarforums.com/forum/x...oolant-190749/

Do I need to open the SC bolt for a complete draining and filling? (I havent been able to find anything that fits).
>>Solved: used the back end of the spark plug socket and a spanner.

Still having difficulty finding the drain plug for the engine block.

 

It's on the left side, near the back of the block. The picture is not very high res but it is probably the thing pointed at by the yellow line.

 

Thanks.
Just submitted a new post combining some questions. I will add this answer there.
https://www.jaguarforums.com/forum/x...-flush-223745/
Could you have a look at my other questions?

 

Dex-Cool is OAT (Organic Acid Technology) based and the Jaguar JLM209723 is ethylene glycol based. Mixing of the two can cause serious problem with the cooling system, i.e. formation of gel-like substance that will clog the system. You should either stick to glycol based coolant (if that is what you currently have in your engine) or, if you want OAT, you have to thoroughly flush every part of the cooling system and be sure that there is no glycol left. This would most probably also require removal of a number of hoses, especially the ones for the charge coolers and a good blow-through with a garden hose..

Otherwise, the colour of the antifreeze is not a reliable indication of which of the two antifreeze types it is. Both come in various colours. One should check the writing on the bottle to to find out whether it is glycol or OAT.