COOLANT LEAK AND WATER PUMP REPLACEMENT

[Johnpor996]

After a run yesterday I found a pool on the garage floor and drips coming from the pipe adjacent to the thermostat housing. Running the car again drips slowly appeared again and after getting underneath the car there appears to be a leak probably behind the water pump drive flange, or it is the gasket in that area.

In any event it looks like it might possibly be coming through the water pump driveshaft bearing – anybody know if this is likely? The car is 20 years old, 3.6 L, 70,000 miles and I doubt if the water pump has previously been replaced.

Replacing the pump looks like a fairly involved job, particular getting stuff out of the way and removing pipes etc. From what I see online the other difficulty is draining current off but in particular refilling it

If anybody has advice I would much appreciate it

Thanks

 

[T8]

This might help

https://www.pelicanparts.com/techar...TER-Water_Pump_and_Thermostat_Replacement.htm

 

[gbarron]

I recently replaced the coolant expansion tank, water pump, & thermostat on my '98 C2. I found the water pump/t-stat the easier part of the job. I purchased a Uview vacuum tool kit and followed this procedure which worked perfectly: https://rennlist.com/forums/996-for...dated-w-refill-procedure-water-pump-tips.html

 

[Alex]

My water pump did exactly that. My mechanic charged me 3.5 hours labour to do the job. Water pump was £220.

 

[Wh1t3Kn1ght]

I recently replaced the coolant expansion tank, water pump, & thermostat on my '98 C2. I found the water pump/t-stat the easier part of the job. I purchased a Uview vacuum tool kit and followed this procedure which worked perfectly: https://rennlist.com/forums/996-for...dated-w-refill-procedure-water-pump-tips.html

Did the same job also a couple of weeks ago and used that guide posted in the link above along with the workshop manual. I also posted some steps in my thread here (a little way down - http://911uk.com/viewtopic.php?t=130461&start=40).

Most important thing when refilling is that you need to rev the engine to around 2500 rpm (after initially filling to the minimum line on the tank) to get the rest of the coolant into the system. This means you either need two people (one to hold the throttle and the other fill or a pedal clamp). Also helps to get the back end up in the air on some ramps or stands.

You don't need a vacuum device if you do it properly as per the guide and WSM. If you need a link to the workshop manuals just holler (think there might be a sticky on here somewhere with the details). I measured all 22.5 litres out and then back in.

 

[Johnpor996]

COOLANT - WATER PUMP REPLACEMENT

Many thanks for the great responses – very helpful.

A further thought – if the coolant in the system is good and doesn't need changing then working with the rear end of the car up in the year on stands presumably prevents most of the coolant coming out keeps the radiators and lines to the radiators full. I noticed in some other guides not associated with Porsche that where you don't want to lose coolant it is common to clamp flexible hoses before removing – in the case of the 996 if you did this I would imagine you would simply lose coolant from the engine block but not the whole system.

Has anybody tried that and how successful was it?

 

[Alex]

There's about 4 coolant pipes running front to back and 2 are around 2" diameter. personally I'd just lift the rear end as high as possible.

 

[Wh1t3Kn1ght]

Yes as Alex said keep the car high at the rear to avoid losing coolant. The only possible issue with keeping coolant in the system is -

A. Do you know when it was last changed?
B. Do you know exactly what type is in the system?

Some say that the Porsche coolant is lifetime fill but you don't know how many times the system has been opened or flushed before you owned the car. Plus mixing some types of coolant can cause issues.

Personally if it was me and I wasn't aware of it being done previously in the car's history I would drain and flush with water before filling with G30 or G40 antifreeze 50/50 mix.