what coolent

[Baza]

I need to change my coolant and would like to know what coolant everybody uses and how you rate it?

Thanx BAZA

[Techno Duck]

You can use anything, just make sure its phosphate free and safe for aluminum engines. Coolant WILL destroy the head in particular if its not safe for aluminum.

[Jason Judd]

I've heard that for those who don't have to worry about freezing temp's, that 100% water is more efficient than 50/50 water/coolant.

Something about water being more efficient at dispersing heat than a water/coolant combo.

Maybe the track junkies know more about this.

Jason

[bearone2]

50/50 is better. higher boiling point and freeze protection.

[Razorback1980]

I'm not an antifreeze expert, but I do know that 50/50 is recommended for higher boiling point/freeze protection and corrosion prevention. But over 70/30 and boiling point/freeze protection and corrosion prevention actually decreases. As for water cooling better than the mix, I couldn't find information on that but it would be interesting to know for sure. Phosphate free, that's a requirement mostly for Europe more so than the US. Apparently the phosphate which is added for corrosion protection will cause deposits in European water and not so much so in the US....according to Prestone anyway. Since Porsche designs cars in Europe, it makes sense they would recommend phosphate free coolant. The part I would like to learn about but couldn't find anything about was which antifreeze was unsafe for aluminum engines and why. What ingredient is added that makes it unsafe for aluminum engines? Anyone know this?

[Techno Duck]

I have seen heads come off 944's that have pitting in them because of the wrong coolant used. I am not sure how much that is attributed to not using a aluminum safe coolant or just not changing the coolant in the 20 years the car has been on the road.

One thing i know for sure of is to not mix the Dexcool stuff with regular green antifreeze. It causes whatever is in the cooling system to litreally turn into sludge.

[Eldorado]

yep.. mixing pink with green = bad...
but pink (or orange?) was the only phosphate free antifreeze i could find at the hardware store up here... and there was green in it to begin with...

whatever is in there now is what my mechanic put in at the start of last winter season when i asked him to give it a coolant flush.

[Mike B]

I use the blue stuff sold at VW parts counters.

[Baza]

Can anyone recomend a brand of coolant?

[Dtchy]

I use Prestone...the orange coolant.

[Techno Duck]

I use regular Prestone antifreeze. Its labeled under 'Extended Life' now. Its the regular green stuff in the yellow gallon jug. Im actually not sure if its phosphate free, but it does say safe for aluminum engines.

The orange stuff is Dexcool. Its my understanding that Dexcool is okay when the entire system is ONLY Dexcool and water. Mising Dexcool with regular antifreeze is where you will run into problems.

Ive been running it in both my 924S when i woned it and my 944 since ive bought it and never had problems, recently took the head off on my car and it looks fine.

[mlue]

Originally posted by Mike B
I use the blue stuff sold at VW parts counters.

I do too but last month when I checked the price VW wanted $28 for a jug in Toronto. It explains why I looked at this thread.

[Zero10]

Zerex G05, Dexcool, Prestone yellow, Celsius universal, NAPA universal, VW G11
Take your pick from the above they are all fine.
Don't mix dexcool with any of the others and always flush your cooling system every 3-5 years.

[TheCooler]

I got g12 for mine.

[Razorback1980]

Prestone Extended Life

[hoover]

Mobil do an antifreeze recommended for porsche, phosphate free, also distilled water should be used.

[surfdog4]

You don't want to use plain water, even if you are in no danger of freezing. Hot Water is very corrosive, and the Ethylene Glycol in regular antifreeze is there to make it less corrosive (and not freeze). It does reduce the ability of the water to conduct heat, so you dont want to go to very high coolant/water ratio.

[Razorback1980]

Actually ph balanced water (distilled) is completely noncorrosive at any temperature which is why distilled water is recommended. It is the metal content within unpure water that makes corrosion. Corrosion occurs with two dissimilar metals have an electronic connection between them. The better the current path the more corrosion occurs. Salt water for example is more conductive to electricity than tap water, therefore more corrosion occurs in salt water than fresh water. That's the basis of cathodic protection. I used to work for the National Association of Corrosion Engineers based here in Houston and have read much more on the subject than I really cared to...but it is pretty interesting. Antifreeze reduces corrosion by increasing the resistance to electrical current. The negative side to reducing electrical current is that it takes away the heat transfer properties as well. So if you do use pure water, make sure it is distilled.

[TSNAPCRACKLEPOP]

do you guys put the "pills" in the engine? cadillac uses them in some of their engines, its some organic mix pill to reduce corrosion, available from the dealer parts counter.

[Razorback1980]

I don't use them, I just use antifreeze which does almost as good a job. If you keep your coolant changed and just use antifreeze, the engines will last a very very long time without suffering from corrosion.