how much fluid to change rad ?

changing my rad and was wondering how much coolant/antifreeze i will need, the last rad that was changed they used a litre ? it holds 22 litres i think, and was wondering how much to buy as mixed its nearly £20 gallon wich is a joke,and dont want to buy 20 litres when i only need 5.they used 10 litres to change header tank it doesnt add up ? if it holds 20 litres do replace the lot heeeeeeeeeeeeeeeeelp

Hi, when I changed my expansion tank, I drained it into a bucket & then re-used it. Obviously I only needed to drain enough to get to the expansion tank and you will have more, so have 4 buckets ready just in case!! But you shouldn't need to buy more than 1 ltr neat to top up once refilled. The system is lifetime filled at factory so just re-use whats in there and top up with neat as necessary. Steve

loose it all yep but i probally lost a bit,and can you mix longlife red with the blue ? :dont know: is there a drain point anywhere on the car,i thought it should be 50/50 coolant antifreeze mix, sure its not a liftime fix it should be changed after certain millage anyway.

I bought the coolant from design 911, bright pink, I'm not sure if you can mix it, someone will chip in with that. The drain point for the coolant system is at the rear/ centre of the engine near the rear bumper at the back of the car, it's the bolt with the female hex/ allen key fitting. There may be a drain point towards the front of the car but not that I know of.

Usually you need about 3 litres of coolant/water mix when you are changing the radiator. Buy 2 litres of Porsche coolant and you should be fine. The trick when refilling is to leave the small vent hose off and connect the 2 main radiator hoses. Refill via the coolant tank slowly until coolant emerges from the vent tube and reconnect it. Then start the car and let the thing warm up properly. When fully warm take it for a run revving the engine every so often past 5000rpm and you shold purge the air. Keep an eye on the coolant level over a couple of weeks as it would drop as air purges. I didn't have any airlocks when I replaced mine and left the vent hose off while refilling. The original coolant in your car (yellowish) is an Organic Acid (OAT) type. These are known as silicate-free coolants. They are supposed to last for life. Older blue coolants had to be replaced as they contained silicates that get used up over time. The later pink/red coolants are a newer technology called Hybrid Organic Acid (HOAT) which is actually an OAT coolant with some type of silicate. The are also supposed to last the lifetime of the car. You are not supposed to mix any OAT/HOAT coolants with the older silicate type as you end up with this brown sludge in you system. However the newer HOAT ones can be added to OAT coolants hence the new Porsche pink coolant can be added to the older yellowish coolant in the older 996s.

Never mix Long-life (Pink or Red) with Ethylene Glycol (Blue or Green) as this has undesired reactions. My advice would be drain the lot or as much as you can, there is a drain tap at the rear of the engine in the lowest part of the water jacket, remove this to get all the rear out. Then disconnect the lower rad hose on the side you are not doing, then the side you are doing will be drained any way. While the plug is out and both at the front are disconnected pour a few watering cans through to flush it out fully. Now you have a fresh plate. Reconnect hoses, fit new rad, put the plug back in. Fill the system with about 10 litres of tap water and then check that you have no leaks Now add 3 litres of the Long life (this is more money than Ethy/Gly but MUCH better properties) Once thats done bring to level as best as you can by squeezing hoses that you can get to. Start car and let it start to warm - still with the expansion cap off Constantly keep checking for leaks, attend if required and keep topping up. Once near to normal running temp, get someone to hold revs at 2 - 3000RPM while you get in more water. Once you are happy it is dropping no further take it on a short run, then check again, top up if required. Regards Lloyd

Nice one Lloyd, all the facts delivered in easy to follow instructions as usual!! Don't ever leave this forum!! Steve

Minny you beat me to it, we are pretty much on the same wave length and yes, a great additional tip to leave the purge clip in the upright position for a week or so :thumb:

Sorry!! Wrong of me not to big up Minny with his data too!! You guys are all so helpful to us mere mechanical minions, we really appreciate it & it gives us the confidence to do these things for ourselves. Lloyd, how did your expansion tank glue gun fix hold up? (don't mean to hijack the thread here Patgas!)

Thanks for the compliment Steve.. quite touched

Both the long life pink/red/yellowish coolants and older blue ones are all ethylene glycol coolants. It is the additive package that differs and the mixing that causes problems. Mixing the newer OAT/HOAT (long life) coolants with the older silicate one is what causes the problem. You get this horrible brown sludge that can clog passages. What complicates the older silicate coolants was that they could also contain phosphates, nitrites, amines or none of the 3 depending on the specification. Thanks for the compliment. Glad to see everyone else do the right thing spending time on the forum rather than watching some house type program on tv at the moment.

Yeah... sorry Patgas... It didn't last :sad: I put it to a bit of extreme, got stuck in a big traffic jam, next day I saw the glue has melted and dripped onto the chassis B U T ..... Lloydie doesn't give up that easy, I am biting the bullet and replacing the tank but sending the old tank off to my tank-building buddies to build a bomb-proof braised, polished alloy version. The plan is all you need do is remove your leaky silly chocolate teapot type, take the two caps off and transfer them to the shinny polished race spec tank Down side = difficult to check coolant level HUGGGGEEEE Plus side- no more leaks again, ever... no never ever :mrgreen: (unless you accidently drill it!)

Hmmm, was wondering if it would last for you, it does get mighty hot. The new tanks have extra fins to support where they usually split, I'm hoping they will stop it from going again. Alloy tank sounds cool but pricey!! I've held on to my old one, might find someone to mend it properly as a spare.

water 10 litres water? didnt think you should use water and add 3 litres if long life,what pre mixed or just long life anti freeze, seems to be a bit of conflict in how much it holds and exactly what to use,it says in manuall it holds 22 litres.and was told not to use water,you guys say 1 litre neat ?what anti freeze or coolant surely you are looking for 50/50 mix or buy pre mixed yes

To be fair, I use deionised water whenever I make up a 50/50 coolant water mix.