FAQ: 944 Coolant Fluid Types/Options

[phoenix_iii]

I would like to have a nice clean post that outlines what kind of Coolant to put in the 924/944/968. I have an 85.5 NA.

If you know for certain, please post the
Vehicle Model/Year
Type of Coolant Recommended
Amount of Coolant for the whole system
Replacement Interval
Tips/tricks/alternative addatives?

Thanks!

As per aj951 - http://www.clarks-garage.com/shop-manual/cool-02.htm

[aj951]

Vehicle Model/Year : 944 Turbo/ 1989
Type of Coolant Recommended: Pentosin Lifetime (RED)
Amount of Coolant for the whole system: Approx 3.5 L of coolant only, if mixed 50/50 with distilled water.
Replacement Interval: Every 2 Years
Tips/tricks/alternative addatives?: Flush the old coolant out really well and after refilling, bleed the system of any air. Clark's garage has a really good procedure for this. I also recommend using a pressure tester to help bleed the system.

[Bendavis2]

1983 Porsche 944

The right answer: Any phosphate-free coolant is best. Check the labels. Mixed with distilled water makes it better. Coolant which says: "Good for aluminum engines" may still have phosphates, and is NOT acceptable, and is probably just a high alkali formula.

Tips: Drain the system completely, flush, and put the new stuff in. Bleed as per clarks-garage.com instructions

The other answer: The reason we use phosphate-free coolant is because it prevents the minerals in hard water from precipitating out and clogging up the radiator. This problem is most severe with water that has a high mineral content. Several enthusiasts have noted, however, that most water in the US doesn't have a high enough mineral content for you to worry about this, and that useing plain old coolant is just fine. Or, plain old coolant with distilled water. Many have done this without problems. So if you can't find any phosphate free coolant, then you might be safe; but you might as well spend a few extra bucks and get the phosphate-free stuff.

The coolant volume on early 944 models is 7.6 litres, I think.

Replace every 2-3 years.

[944 boy]

1988 944 N/A
Coolant/antifreeze: Pentosin Red 50/50 with distilled H20
Coolant for track use: Distilled H20 + water wetter

I have used many types in the past. Strait water has served me well in 120+ temps with only one fan working on low. The trick is to have the rest of the cooling system in top shape.

[Aslet]

Can you clarify something for me please... Why do you mix with water or use just water? I guess to help clarify, what is coolant? It is water with chemicals so it doesn't freeze....? I just always thought you would use pure coolant and that it maybe conducted heat better, so was more affective...

-Randy

[aj951]

Well..I used the term coolant above interchangeably meaning antifreeze only (approx 3.5L) and antifreeze mixed with water (3.5L coolant + 3.5L distilled water), so perhaps that was confusing. For everyday street use most people use a coolant mix of antifreeze and water. The antifreeze provides corrosion protection, freeze protection, conditions the seals and lubricates the water pump, however, the sacrifice is giving up some cooling efficiency. For track use people use water because it provides better cooling and if you burst a hose, you don't lay down slippery antifreeze all over the track.

[HondaDustR]

1987 924S

I use Prestone Dexcool and have not had any problems with it. It says it is recomended for aluminum engines and radiators, and also specificaly states that it is phosphate and silicate free (not to mention it is readily available at any auto parts store and is actually slightly cheaper than regular Prestone). I mix it 50/50 with distilled water to be sure it's not going to screw anything up.

Capacity is technically 2.2 gallons, but you'll need more for bleeding the air out.

As far as replacement intervals, I don't know, but definitely not 5 years like Prestone says is possible (reason why GM had problems with Dexcool in the first place...it starts doing strange things when it gets that old). I would do it every 1-2 years. Personally, in the 1.5 years I've had my car, it's had about 4 changes of coolant after various repairs involving contaminating and/or spilling the drained coolant.

Water whetter is good stuff to use.
Also, people say a pressure tester is helpful for getting the air out, but I just dismount the expansion tank and elevate it so that it forces a consistent flow out the bleeder valve. I do it for initial fillup, then as soon as I start the engine, and once again after the thermostat opens. Blipping the throttle slightly seems to help dislodge bubbles at the last stage. I've had perfect results without wasting so much coolant with this technique.

[924Sman]

Dexcool is fine, or any coolant designed for light alloy engines/radiators. I use it exclusively w Water Wetter.....7.8 liters total capacity includes heater core. Mix according to the coolant bottle and the protection you need/want.
Lift the front end up ever so slightly to allow air to "rise" towards the bleed screw. Barely open the screw then fill until a stream of coolant comes out w/o air bubbles then tighten it. Make sure the heater core is at least on the warm setting or full heat to allow the core to fill.

Dal

[VintageGearMan]

Originally Posted by aj951

Well..I used the term coolant above interchangeably meaning antifreeze only (approx 3.5L) and antifreeze mixed with water (3.5L coolant + 3.5L distilled water), so perhaps that was confusing. For everyday street use most people use a coolant mix of antifreeze and water. The antifreeze provides corrosion protection, freeze protection, conditions the seals and lubricates the water pump, however, the sacrifice is giving up some cooling efficiency. For track use people use water because it provides better cooling and if you burst a hose, you don't lay down slippery antifreeze all over the track.

Sorry to bring that up quite a while later hahahaha but so I could put a mix of 3/4 water and 1/4 antifreeze? Can I mix whatever ratio I want? And if so... What was the deal with not the same amount of liquid? 3L of antifreeze or 3L of antifreeze plus 3L of water? What?

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[crash613]

I watched this video.. he demonstrated a good idea of running a tube from the pressure release back to the overfill. This was to bleed the system.

FAQ: 944 Coolant Fluid Types/Options