So my son yesterday went to fill the gas and he noticed at the gas station that he lost the power steering and battery light went on, I had him drove out to the nearby parking lot and shut the car off, he noticed the engine temp gauge is in red and some coolant came out under the car. I know that it must be the serpentine belt either slipped out or snapped, so I went to the parking log, we took out the engine cover in the cabin firewall, yup, the belt slipped out but not broken, so after I removed the belt I found out that the water pump pulley was lying on top of the plastic under belly cover, I picked it up and it snapped off the WP bearing, I can see the bearing ***** and coolant is leaking from there. This is crazy, I have seen water pump failure, the bearing worn out but had never seen the pulley can snap off!

Anyway, called AAA to get car towed home, ordered a water pump kits with low temp thermostat from Pelican Parts, and serpentine belt, expansion tank has no leak which is a good, replacing water pump and thermostat do not seem to be a difficult job but will be messy, anyhow, waiting the parts to come.

 

good time to flush the system .. 16 litres or so ... if its an S its about 20. I changed over to the latest colour purple.

 

So the Prestone green coolant is not okay? What type of coolant should I use? I think currently the system has Prestone green coolant.

 

oh its perfectly fine ... that is what the car was spec'd with .

Porsches new coolant for every car is the purple.
i was just saying if you were due to flush and replace the whole coolant anyway , would be a good time to upgrade if you were thinking about it.

 

Check and make certain the entire composite vanes are still present on the inside of the water pump.
If any pieces (even tiny ones) are missing, I would flush the engine, backwards, and look for missing pieces.
Any missing parts could be caught in the heads which can cause hotspots where the head can crack.

Porsche coolant for the M96 should be pink-ish.
Pentosin coolant also works well.
Use a Coolant refill vacuum system like this:


This will pull all of the coolant from the system, and also make filling without air bubbles simple.
It is universal, so it can be used with your other vehicles.
It takes all the guesswork out of purging air from the system.
It does require an air compressor.
But a cheap small pancake compressor should be able to do the job.

 

I just did this about 4 months ago. It is pretty simple when you remove the water pump in the same area there are two hoses that go to the front radiators, disconnect them and let the front drain out. Make sure to remove the cap in the trunk to let air in. If possible make sure the car is level to allow everything to drain. replace the pump and connect the hoses again. I did a few flushes with distilled water to wash anything out before putting in the coolant. After the flushes just pour in the new coolant till you see the mark on the reservoir look correct. This is very important you must keep the blue cap on tight as the system requires pressure to work correctly, it has a release valve inside. I would recommend buying a new one as they can get jammed with gunk over time. Start the car and watch the reservoir levels, it will most likely drop and you need to add, so stop the car add more and repeat. Repeat this till the level stays at the correct level.

One tip that helps to purge air is that where the oil / coolant gets added there is a plastic "bottom" but it is actually only a cover. It hides a vale system that you can use while the car is running to release air pressure as the system heats up and purges air bubbles. You don't need the coolant pressure system unless you want to spend the money, it does make it easier but is not required.

 

the "floor"

The floor remove

the release value pull the metal handle up to release air.

 

and don't forget to put the ignition on and put heater on high before draining ( do not start car obviously ) you just want to open the heater valve to allow coolant flow.

 

totally forgot about that. I recall I warmed the car up a bit then put the heat on high and fan at max, once hot air was flowing I turned the car off. Nice catch Ice

 

i agree , but that would be difficult for him with a snapped off pulley though lol..

 

but I though he was going to replace the water pump at the same time and it should have a new pulley, right?

 

oh yeah if he flushes after he puts the new pump in.. right.. when mine failed i dumped it all before putting new pump in .. need a REALLY big bucket lol.. i used a container that used to use driveway sealer.

 

Okay, I got broken water pump and old thermostat removed, and got new water pump and new low temp (73c) thermostat with new housing installed today. Drained about 3 or 4 gallons of old coolant, very dirty, I raised the front the car higher than the rear to get as much coolant to as possible. The center drain plug was stripped so I only drained the coolant from the water pump hose and thermostat hose.

I filled 2.5 gallons of distilled water and expansion tank is full, after started engine and I was able to fill another gallon then it won't take anymore (I do have the purge valve opened), so I went to get the car heat on max and brought it to operation temperature then hold the engine between 2500 ~ 3000 rpm for about 10 minutes, thermostat was open and radiator fans went on so the system was circulating. I shut off the car and it was going to get dark so I am done today. Tomorrow I will try to fill more distilled water if it can take more. I ordered a coolant vacuum kit from Amazon and just arrived after I was done initial filling and bleeding. So tomorrow I will drain the distilled water and try this coolant vacuum fill kit.

Here are the old broken water pump, the bearing is shot, all 6 fins on the propeller are broken on the tips:




New water pump and thermostat installed


New water pump (Pierburg) and new low temp thermostat:

 

Stop right there!

Have you accounted for all the broken fin bits? Those darn things can get lodged in your coolant passageways, leading to hotspots and overheating.

You should flush them out.

I would remove the thermostat, remove the water pump, and spray compressed air into the thermostat hose that leads to the radiators. Coolant/water will exit from the thermostat and water pump location. It’ll be messy, but you really ought to remove as much debris as possible.

 

I drained the coolant from thermostat hose and water pump hose, didn't see any of those plastic fin bits, I will drain the system again and see if they are flushed out, if not then what? Just checked, the coolant (water) level is down about 1/4 tank.