Porsche Enthusiasts Club Forum

Hi All
Just in the process of getting my car ready for back on the road in March, Just been doing a bit of maintenance by replacing the inter-cooler hoses with silicone and I've swapped both the radiator hoses (due to a slight leak) and replaced the thermostat.
I now need to flush out any old coolant and replace with new, im sure this has been asked before so i apologise for the repeat question but what type of Antifreeze do people use?
Also is there any tips for replacing and bleeding any air out of the system?
I know it needs to be Phosphate free and i think both of these are but whats the significant s over colour ie red blue, at present the coolant is red.

I'm familiar with the millers antifreeze and do like miller as a company
http://www.ebay.co.uk/itm/170711002314? ... EBIDX%3AIT


And i noted on here someone recommended this type
http://www.ebay.co.uk/itm/Comma-XSG5L-5 ... 2c96855bd3

Any thoughts please?

Thanks
Mark

It was probably me who suggested G48. Out of the 'Blue' anti-freeze coolants that are not OAT it seems to 'keep' and has the inhibitors lasting a little longer than the others. It is still an OE coolant (with specs to prove) for BMW and Mercedes after all as well as Porsche .

Some people (including me) have had 'pink' OAT coolant in previous 944s without any issues mind you with it lasting quite some time with no sediment forming etc.

I use blue and deionized water. Just re bleed my system today had to replace fan temp switch, complete pig off a job on turbo, hose at coolent neck as slicing hose had developed a leak in the wall. Now this hose wasn't more 4k old and there not really much off hose that carrys coolent, theres only a small gap between the two hard pipes it joins

Had only lost 2.5 Ltrs in the change over but need to added another 3 on top during the bleeding.

Jacked front up. Remove cap. Turn heat to full fans off. Fill and run till temp was nearly running temp. Open bleed screw on coolent neck and run till fans kick in keep topping up as needed sometimes water then anti freeze. Took about 35 minutes before the bubbles stopped at the bleed screw. Turned off car later on noticed the level had dropped below min. Probably from when turbo pump running on after shut down.

My intentions are to do a few short drives stop on a hill and open the bleed screw with the cap on. All the pressure release should come out the bleed screw. Then I can remove cap and add if nessery.

I read somewhere if you use a bleed nipple in the bleed hole you can put a pipe from there back into your header tank so you don't loose all that expensive antifreeze and water

Not sure that would work but a little valve with a pipe connector would be handy

Something like this eBay item number 231404891711

Thanks for the reply

So Miller Red OAT will be fine? http://www.ebay.co.uk/itm/5L-MILLERS-OI ... 2569015ffa

I run blue g48 in my 928 as it meets the spec for porsche pre 1994. I did however run red OAT in my 944 with no problems. What colour is currently in your car? Probably best to stick with whatever is already there as changing could perhaps cause a reaction between the two types. If you do change type then make sure it is well flushed with water

I'd agree with Mike. If you have the Blue stuff in I would go with G48. If it is red stick with that.

If it is very rusty then I would be tempted to flush out the entire cooling system thoroughly, and possibly go with OAT coolant which IME seems to last longer than many short life coolants with benefits (sediment/silt formation being minimal in comparison).

The only reason I said not to go for OAT before was due to the 944 heater being a brass item with soldered joints. There has been plenty of debate as to whether OAT coolants attack the solder (indeed, my old 944 on what I guessed to be G12 (OAT) coolant (with its share of radweld in) did have a leaky matrix (but the entire cooling system was shot for another reason as well). However, others have argued that it is only pre-war soldered rads that it affects and that many vehicles these days run with OAT coolants on soldered radiators (buses being one example).

However, I know that the freshly rebuilt engine in my new car with cheapo Bluecol coolant has already started going rusty within a year (it still smells very much of coolant) as did my Stag (I can appreciate there is an argument for that car but I did flush the entire system (including the engine) until the water ran clean previously), something I have yet to have occur with OAT or G48 .

Thanks for the advice guys, it presently has Red in so I've ordered some Miller Red and will flush out and change this weekend,

is it a pig to change the thermostat or easy?

It is easy but fiddly. You need some circlip pliers to remove the old circlip. Straight ones may do the job (although a lack of room may become a problem (a chassis leg is in the way) but 45 degreed items will do the job (I actually bought some for the job. It was still fiddly to do but easier).

If you are local to Warwick I am happy to lend you you mine (I rarely use the 45 degree angle ones with the straight pliers being more versatile .