So I want to change my antifreeze as it hasen't been changed since who knows when. It is starting to get cold here and this summer I had to add some pure water to the system(I was stupid and opened the cap while it was hot and lost some) so I figure it is a good time to change it up.

They say to use Jaguars antifreeze or a phosphate free alternative. Prestone claims to have a 50/50 Phosphate free mix called PrestoneŽ Dex-CoolŽ Extended Life 50/50 Prediluted Antifreeze/Coolant I think this stuff is red and the stuff in my car is green right now does that matter? Will this work or is there a better alternative?

Also is it worth it to use a radiator flush before adding new?

Thanks

 

The phosphate free brand my local Jag Mechanic has is a brand that I've never heard of. And its expensive. I'm in your situation right now. Changed the Thermostat yesterday and I'm draining the system and doing the flush/fill. Since flushing alone doesn't remove scale and other build-up, I'm using the Prestone Flush/Cleaner (I cant remember the exact name they use) to clean it out. Then I'm filling it with the Phosphate free product you mentioned. With the colors.... (its red vs typical phosphate antifreeze being green) BUT ... my current phosphate free antifreeze is also green. Anyway ... the colors are different so you dont mix it.

UNLESS I'M TOLD OTHERWISE: My current research tells me that mixing the Dex-Cool with other antifreeze could cause major issues. PLUS it dilutes the chemical properties that protect your system. I've also read a report about some corrosion issues that came about when the two are mixed.

So ... I'm draining my system, flushing it completely, then filling with the Phosphate Free Dex-Cool. But I'll be watching this thread close to see if any of the other guys have different thoughts/advice to add.

 

So I did not have the tools to reach the engine block plug without removing exhaust pipes and it was freezing outside so I left it in.

I drained it and refilled with water and drained again. Then I used Prestone flush and drained that. Then I filled the system back up with pure water and ran the engine, opened the plug, and ran about 4 gallons through it untill it ran clean and clear.

I am confident I got all of the old stuff out of there. Was a bit of a job so I hope no one comes on and says I must change my coolant!

 

'You need to change your coolant'! Nah just kidding. LOL

BUT, you did refill with antifreeze and not just plain water?

 

Not a Jag mechanic specifically, but I am an experienced mechanic and I'd tend to stay away from using dex-cool altogether. It has issues all by itself lol. Just my two cents. A cooling system is a cooling system, honestly, I'd say just use 50/50 coolant/water mix with a small bottle of Water Wetter and you should be fine.

The most efficient way to cool an engine is with pure water and a larger water wetter mix, but you only see that with engines that are regularly rebuilt (i.e. race cars). Not to mention, propylene glycol is a pain in the a** to clean up in the event of catastrophic failure lol.

 

I'm in the same situation, got the green stuff and need to change but don't know what to. I know it needs to be phosphate free, does it need to be silicate free too?

Anyone try Evans Waterless Coolant? http://www.evanscooling.com/
I used it in my (old) Mercedes. Diesels with aluminum heads are very touchy about overheating. The system seems to stay clean and I didn't overheat either of my cars. Be sure your system doesn't leak though, it is expensive. What do you all think about Evans in a Jag? Or should I stick with Xerex G-05, Dex-Cool or similar?

 

Yes it is at 50/50 right now with the DEX Cool. It was the only stuff in my area that I could find that was definitively phosphate free.

 

I was just at Advance Auto, and all they had was Prestone (green stuff) and Peak. I didn't want either of those so I left. I think I need Xerex G-05. The Valvoline page says it is approved for Jaguars through 1996. It's phosphate free and low silicate.

 

First, there is nothing wrong with Dex-Cool. There is lots of confusion and "wive's tales" out there, all usually inaccurate. It is a tried and proven OAT formula and Ford/Jaguar has been using is since 1999 in every model. It is a special formula however, and is not compatible with ANY other coolant formulas and cannot be mixed. As long as the coolant system and components were designed to use OAT, then Prestone Dex Cool is that formula.

If you have a pre-1999 Jaguar then your cooling system was designed to be compatible with the traditional green formula. Xerex G-05 is an HOAT formula (hybrid organic acid technology) and is not compatible with OAT (Dex Cool), but is compatible and a long-life alternative to the traditional green.

So - use any - the traditional green, G-05, or Prestone mixes all in a pre-1999 Jaguar engine, any model. If you made a mistake and put in Dex-Cool it should be completely flushed and removed....Pronto!

 

Thanks Steve, I'll go ahead and switch to G-05 in a week or so.

 

Guess I'll have to switch too! It was way too cold for me to wait any longer and I didn't have much to choose from here in Kentucky besides WalMart and pouring Bourbon in it! And I already drank the Bourbon so .....

 

So Jaguar calls for a phosphate free antifreeze, as far as I can find that is the only requirements. On the question of Dex-Cool... we have:

"'You need to change your coolant'! Nah just kidding. LOL

BUT, you did refill with antifreeze and not just plain water? "

and then

"So - use any - the traditional green, G-05, or Prestone mixes all in a pre-1999 Jaguar engine, any model. If you made a mistake and put in Dex-Cool it should be completely flushed and removed....Pronto! "

Translator makes it sound lke no biggie and Steve makes it sound like it will destroy the cooling system.

Since I am out over 40 bucks on the Dex-Cool "mistake" and there is no definitive answer here I am gonna save myself some money and just go to the dealer and say "sell me the antifreeze I need." I will report the results.

 

You're always welcome to use whatever products or do whatever you wish to your own car.

The problem with an OAT formula (Dex-Cool is one) is that it can become highly reactive with some materials, usually gaskets seals and sealants, UNLESS those were designed for use and compatible with OAT. Pre-1999 (with 1999 being a transition mid-model year), Jaguar wasn't designing coolant components to be compatible with OAT so it is a crapshoot that some seal, gasket or sealant will react adversely with the Dex-Cool put in a pre-1999. In other words, I cannot guarantee that a 19xx model Jaguar will experience a coolant meltdown at any particular point in time...but if it were my car, I'd want the OAT out...pronto!

The reaction that OAT has with incompatible materials, and what caused so much controversy with (only) TWO GM models that used an incompatible intake manifold seal is that OAT turns that material to a jelly-like substance which then dislodges, floats around the cooling system until it reaches some small passage where it can act quite efficiently as a plug. This might be coolant passages in and around the cylinder head, heater hoses, gateway valves, heater core and radiator. Any of these conditions have negative consequences of differing varieties. In the case of GM which pioneered OAT, they were too quick to introduce it in every single GM model engine in the 1990s without thorough testing so, as happens often, failures finally caught up in the field with real customers. And, like so often happens, GM wieghed the costs of recalls to lawsuits and concluded it was less expensive for them to roll the dice on the lawsuits.

Meanwhile, Ford was closely observing, and testing in the laboratory (not in customer cars), so when Ford finally released use of OAT formulas in 1999, they were confident there would be no compatibility issues with coolant components. Pre-1999 however, Jaguar specced Dow coolant D542 which is the traditional green formula and weren't necessarily using OAT compatible components. Maybe by accident, but not intentionally.

Back to your car, you can put peanut butter and jelly in if you wish. I'll only wish you luck. I'm not here to sell you on anything, nor am I here to impugn the reputation of or compete with any other poster in reply to your question. I do not anwser any technical questions based on a guess or opinion unless I clearly state that. As an Indy with a customer base of Jaguar and BMW cars, I have to be certain my recommendation has merit and I am confident in my reply.

Best to you in whatever direction you choose to take.


New Mexico is one beautiful place, BTW. Can never get enough of SF...or Hatch Green Chili. Going to see my buddies at Malloy, I take it??

 

My concern was that you had refiled with only plain water. Which at the temperatures we have at the moment, would be frozen solid risking cracked blocks, blown heads etc.

Steve gives a great and detailed explanation, and if it was my car, I would be following his advice.

He has a professional reputation on the line with his customers so can't afford to take risks.

 

Thanks, I just wanted to get the straight scoop. Guess what I am doing this afternoon...

So I went to the dealer(had to get new gaskets for the oil filter deal anyways) and I asked them what coolant they use and if it has to be Phosphate free, they told me "any of the standard green stuff will work, we use the Nissan stuff." He also said that the last techs in there were real sticklers for phosphate free but the new guys do not give it any concern whether it is or not. Before I could even get DEX-Cool out of my mouth he said "Don't use it"

So hope the car can make it another 100 miles before it gets changed :P Thnks for the data Steve, thats what I was looking for.

 

No problem and I really do hope I've helped. Not surprised about the dealer tech comments regarding coolant formulas. In my experience, lots of techs, even factory trained techs do not understand how/where/when to apply these different coolant formulas. The industry did not help itself by creating much confusion. I became frustrated myself and spent countless hours researching, reading and talking to every expert I could find. I've easily over a couple hundred hours into it, and I believe I have a solid grounding in it....but it still bewilders me to hear what comes out of the mouths of techs sometimes.

Make sure that you COMPLETELY flush the old Dex-Cool as it has a water/oil like property to it when in contact with other coolants such as G-05 and traditional green. The heater core is especially difficult to purge.

My process - buy 5/6 gallons of distilled water, plus the correct coolant concentrate. Start by turning the heater on HIGH, fan on HIGH and leave it that way until this entire process is completed. Pull the radiator drain, drain completely, recap, fill the entire system with DISTILLED water (not tap water. This is especially important on an AJ6 with the coolant passages running around the cylinder head studs). Start the engine, take a fifteen minute drive at any speeds. Return and drain the radiator again completely. Refill with pure distilled water again, same drive routine. Do this at least a third time with the heater/fan always on HIGH. The third time you drain the radiator it should look fairly clear. If not, do another cycle. On the final drain/fill use a 50/50 distilled water coolant mixture. Living in NM and driving there mostly, you can also go a 60/40 mixture (more water than coolant). Do one more drive cycle with the heater on high. Let it cool down open the rad cap and top off with a mixture...you're done....now go find a good Gardunos, maybe the one on Montgomery and Juan Tabo and have a beef burrito grande for me!...and a traditional margarita too.

 

Interesting thread, though I was left with more questions than before I got in! I've used Peak Global Lifetime antifreeze with good results before, but I'm not sure it's best in this application. It is phosphate free, though my understanding it is an OAT derivative. Beyond that, internet research hasn't confirmed whether it would be wise to use on my '94. Can anyone weigh in on this?