Coolant Flush
 

Hi there,

I want to flush the coolant on my 95' XJR but I'm having trouble finding the petcock/radiator drain plug. I have read other threads that it is on the passenger side of the radiator but I still can't find it. I will attach a photo of what I saw under there.

Thanks in advance!
https://cimg1.ibsrv.net/gimg/www.jag...c264ffdb02.png
https://cimg4.ibsrv.net/gimg/www.jag...f786c1d1dc.png

If you can't find it I would just undo the bottom hose. Then fill the system up with distilled water, run it for a bit, drain again, and repeat. Finally fill with the proper fresh coolant.

The drain plug is black plastic and has either one slot as shown below or possibly two slots in an X pattern. I can't remember if it's closer to the left or right end. The "arrow" end of the plug helps prevent it from falling into your catch pan if you loosen the plug all the way.

https://cimg3.ibsrv.net/gimg/www.jag...c79bfbe358.png
I can't tell about that first photo, but the object in your second photo looks like a radiator mounting stud. There are two molded into the bottom of the radiator that sit in foam bushings to hold the radiator in place and protect it somewhat from vibration. Your bushings are deteriorated and it would be a good idea to replace them, along with the smaller ones that isolate the air conditioning condenser, which can develop a leak if the bushings aren't replaced and the soft aluminum condenser rubs against a hard steel brace.

As AJ16er suggested, it's about as easy to just disconnect the lower radiator hose, though it's a bit messier. Whether it's more likely that the head of the drain plug will snap off or the ridge around the lower hose plastic fitting will break off is anyone's guess, so whichever method you choose, be very careful with these old plastic parts.

Cheers,

Don

G’day Shinda,

That looks like the drain plug in your first pic. Undo it and you should see a captive plug as in the other post.

Cheers,
Jeff.

Not meaning to hijack the original poster's thread, but what brand of coolant is generally preferred in a moderate temperature region?
(Only occasionally gets at all below freezing here.)
thx

Hi montoya66,

Jaguar's coolant recommendations vary by year, model and engine. The short answer is that brand is generally irrelevant, it's the chemistry that matters. Let us know the year, model and engine of your Jag and I'll move your post to start a new thread.

Cheers,

Don

1995 XJ6 Coolant recommendation?
 

Apologies if this has been addressed before, mine is a 1995 XJ6 X300 with the straight six of course, thanks

G-05 or regular green would be my guess. Maybe somebody knows for sure.

Apologies for bringing this thread up. I’m looking at flushing the coolant and re-filling with fresh stuff this weekend.
Am I correct in thinking you leave the drain plug OFF whilst doing the cycles of distilled water, and only fit it again prior to putting the new coolant in?

Hi Marc,

Welcome to the Jaguar Forums! It's great to have you with us.

You don't tell us the year, model and engine of your Jaguar, so the procedure for flushing and changing the coolant may differ depending on those details. But here is a quick description of one way to do it. Adapt as necessary to your model:

Loosen the radiator petcock/drain plug or lower radiator hose and drain as much old coolant as possible into a catch pan. Tighten the petcock/plug or reconnect the hose. Add distilled water to the system until full. With the reservoir cap off, run the engine until the thermostat opens, continuing to add distilled water as necessary to keep the reservoir full. Shut off engine. Drain coolant again and repeat procedure two more times. Drain system, close petcock/drain plug or reconnect hose, and add pure anti-freeze concentrate to the reservoir until full. Do not add 50/50 coolant mix. Remember that about half of the cooling system remains full when you drain from the radiator, so after your flushing process, it will be about half full of distilled water. So adding anti-freeze concentrate will bring you close to a 50/50 final mix.

Run the engine and continue adding concentrate until all the air is bled from the system and the reservoir is full. Replace the reservoir cap and allow the engine to cool. Then remove the cap and top up the reservoir with concentrate.

There are other methods that work fine too. One is to use 50/50 coolant mix as your flushing agent instead of distilled water. This adds a bit of expense to the process, but results in a more predictable final mix.

Regarding coolant selection, if you'll let us know the year, model and engine of your Jaguar we'll be happy to offer advice.

In the meantime, please visit the New Member Area - Intro a MUST and post an introduction so we can learn something about you and your Jaguar and give you a proper welcome.

Cheers,

Don

Hi there. Hope I’m replying correctly here.
My Jaguar is a 1997 3.2 AJ16.

I changed the thermostat on Sunday and like a novice I added the rubber O ring, which resulted in a cracked thermostat housing. I have that on order and thought it would be a good time to change the coolant as it looked murky and rusty.
I weren’t too sure what type to replace with as the Jaguar branded stuff at SNG Barratt is quite pricey. Also, not sure if 5litres would be sufficient.

Your car would probably have originally been filled with Jaguar D542 (Dow 542) coolant, which was yellow in color. It is no longer available. Some people are under the impression that Zerex G05 HOAT is equivalent to D542, but they are not the same chemically, and I do not recommend G05 in your Jaguar.

On later cars D542 was replaced by orange OAT Extended Life coolant. DexCool, the General Motors brand, is the most widely-available product in the U.S.

Earlier X300s were originally filled with conventional green IAT ethylene glycol coolant (Jaguar D985).

Since you are flushing your entire system, you can use conventional green ethylene glycol, which will be the least expensive type, or you can use orange DexCool OAT Extended Life. The important thing is that you do not want to mix coolant types (IAT, OAT, HOAT) as the corrosion inhibitors and other additives are incompatible and when mixed can form gel, sludge or sediment in your cooling system.

Cheers,

Don

+1

If I'm doing a leisurely coolant change, I like to drain, back flush, fill with plain water and run up to temperature with the heater on full to ensure circulation through the matrix. Cool, drain and flush again before filling with 50/50 mixture of coolant/distilled water. If you do it this way you can safely use OAT.

Graham

I'm rather confused regarding all these alternative coolants! In my 1995 XJR I use Jaguar branded Antifreeze (mixed 50/50 with distilled water) part number JLM204042 and this is yellow. I usually buy it from British Car Parts. The label states it contains Monoethylene Glycol (107-21-1) and passes ASTM D3306

Part numbers for Jaguar D542 (Dow 542) coolant are:

JLM20404/1
JLM20404/2 - 1 Liter
JLM20404/3 - 5 Liters
JLM20404/4 - 25 Liters
JLM20404/5

Part numbers /1 and /5 are listed as discontinued.

Since D542 is not listed as a current product of Dow, I do not know what product is now being offered by Jaguar under the above part numbers, or who the manufacturer may be.

I am attaching the Material Safety Data Sheet for Jaguar D542, which shows that it is based on Ethane-1,2-diol (the IUPAC name for monoethylene glycol/ethylene glycol) 107-21-1. The Jaguar part numbers are given on the last page of the pdf.

It is interesting that the MSDS lists the Contact Person's email at rle.de. RLE is a large automotive-industry engineering firm based in Germany.

Cheers,

Don

the new coolant’s chemistry is unknown. all we know is that the JLM coolant contains silicates and borates. the only other coolants avaliable in europe, off the shelf and wholesale, that have both are the early HOATs, G05 and G11/G48.

unlike those two it doesn’t have an organic acid (sodium benzoate) listed in the sds. if it lacks both phosphates or any kind of organic additive this coolant is garbage.

The attached chart I compiled some time ago may be of assistance.
Chart is basically a work in progress, info on the earlier D985 & D542 coolants is hard to come by, I welcome any accurate changes that may be suggested.

John Herbert
(1996 XJR )

Thanks for that, now we know D542 contains nitrite.

The only available coolant that contains silicates, boron, and nitrite is BASF G05.

Hi John,

Thank you for posting your work-in-progress coolant chart. Very interesting!

Regarding D542, I have not found sufficient data to determine whether it is of the IAT, OAT or HOAT type. Here's what we can say with certainty:

It is based on ethylene glycol (monoethylene glycol and Ethane-1,2-diol are synonyms);

It contains Sodium Hydroxide, also known as lye or caustic soda, which is strongly alkaline and contains no carbon (and is therefore considered inorganic);

It contains Disodium Tetraborate Pentahydrate, one of the chemicals also known as Borax, which also contains no carbon;

Since companies are only required to list chemicals with known risk factors (toxicity, flammability, etc.), we don't know if there are other additives in D542. So from the available data, we can't determine whether it is strictly an Inorganic Additive Technology coolant or possibly a Hybrid Inorganic Acid Technology coolant if one of the other, non-toxic additives contains carbon. But since Sodium Hydroxide reacts strongly with mineral acids, it seems unlikely that D542 is an HOAT coolant, since most organic and inorganic acids have at least some toxicity and would therefore require itemization on the MSDS.

How were you able to confirm that D542 contains nitrites? Was that from the MAN literature?

D542 is definitely not chemically equivalent to BASF/Zerex G05, as has been widely speculated on the forums. G05 does contain Sodium Benzoate, an organic acid containing carbon, which forms Benzoic Acid when mixed with water. It also contains diethylene glycol in addition to the ethylene glycol base. Since it contains both organic (Sodium Benzoate) and inorganic (Sodium Tetraborate) additives, it is classified as an HOAT anti-freeze. I am attaching the MSDS for comparison.

Cheers,

Don

lye isn’t present in G05 concentrate. subaru coolant however at one point used lye in combination with benzoate, they are not mutually exclusive.

Scania believes D542 to be nitrite free and equivalent to G48, MAN refers to it as a nitrite containing coolant.

https://til.scania.com/idcplg?IdcSer...OPM_0000239_01

https://www.cankaltd.com.tr/image/Te.../MANFuelsS.pdf

conclusion: just flush