Mister Quickie

My coolant level was low so I added tap water. A non Porsche expert mentioned that for a Porsche you're only supposed to use a special coolant. Any truth to this or just another drunk guy at a pub showing off his wisdom to impress the surrounding girls in hopes of getting lucky?

JFP in PA

A couple of points: In a pinch, you can add distilled water (only) to one of these cooling systems without harm. You should never use tap water; the minerals in it shorten the life of the otherwise long life coolant and cause corrosion. Second, Porsche uses a coolant that is well known to be incompatible with other products, resulting in the formation of gel in the system that clogs everything. Cleaning out one of these gelled systems is just short of a nightmare.

If the system is fully drained and flushed, you can use just about any phosphate and silica free coolant; only problem is that anyone that works on these cars regularly knows about the potential for gelation, and will top up the car with the Porsche coolant, resulting in problems. If we get a car in the shop that we don’t know the history of, we will only add distilled water.

Mister Quickie

Yikes, yesterday AM I added 16 oz of tap water and have driven just over 60 miles since then. What should I do, should I take it in?

Divot

First, did the drunk guy get lucky?

I've added distilled in a pinch, but not tap. I would play it safe and have it drained and replaced. The coolant is sick-expensive, too.

logray

Ditto on getting the tap water out, but it wouldn't cause a problem immediately.

You can flush with tap, but the final fill should always be distilled and coolant.

FWIW I replaced ALL of my old coolant using Peak Global (silicate/phosphate free) and intend to affix a badge on the coolant tank warning it is not using OEM coolant.

Mister Quickie

I called the dealer, they said not to worry about 16 oz of water since the system holds 4 gallons (4 x 128 oz) making 16 oz 1/32 of the total volume

I'll make sure I only use distilled water going forward

Mister Quickie

PS alas none of the ladies were receptive to the inebriated gentleman's query: "wanna see my place?"

Divot

FIFY

grdtii

What about Prestone which is premixed at 50/50? Could that cause a problem?

rpm's S2

Use the Porsche approved coolant. False economy on stuff like this is foolish.

C4CRNA

The question is why was the coolant low?

RPMulli

Adding only 16oz of tap isnt a big deal... next time use distilled of course!

Mister Quickie

@C4CRNA ... god question, this isn't the first time this has happened. I should buy some Porsche coolant to have on hand for these minor refills.

Mister Quickie

I went to the dealer and bought a gallon of Porsche coolant for $56, ouch!

FWIW I was told this contains lubricants and other chemicals that make it special/better and not only must be used in Porsche engines but also cannot be used in other cars.

VGM911

If I recall correctly, you bought Porsche antifreeze. Once mixed with water in a 50/50 ratio, you have coolant.

So....it's coolant that you add to your car's cooling system. Voila!