dennis hiip

I just installed the IMS Guardian and then discovered that the expansion tank was leaking. Replaced the tank. Now I'm wondering if I should replace the water pump as a preventative measure. It's not leaking or making bearing noise. I've been reading old threads indicating that the plastic water pump impeller degrades with time and fragments can plug capillary coolant passages in the heads leading to catastrophic engine damage(as per Jake). My car is an '03 and apparently this problem happens mostly in pre ' 02's(as per Jake) . What about post '02's? Apparently the head design changed in '02 but I'm wondering if later model 996's are still vulnerable. My car is at 79K. Should I just wait until replacement is indicated? What about after market pumps with metal impellers that are less costly that OEM. Are those a pumps a good idea? Input is appreciated.

UPDATE: Today I replaced my water pump and the old pump's impeller is chipped. I hope I caught it in time before catastrophe , but I am worried where that tiny chip is lodged. Also, changed the coils Four were cracked.

jrgordonsenior

I was told once the 997S pump is a bolt on replacement with larger fins which should provide better cooling....

jeneric996

I would wait until it started to weep or leak. I think weeping or leaking will occur before the impeller breaks apart. Impeller breaks after the bearing fails, causing the impeller to bounce inside the housing.

It may be better to have small plastic parts in the system than have the metal blades scratch the engine housing.

Flat6 Innovations

By the time it makes noise or leaks it may have already shed plastic impeller debris that can end up in the cylinder heads.. While the majority of the failures that we see with cracked heads come from the 2000-01 engines we have seen this happen to engines as late a 2006. No matter mileage we change water pumps every 3 years, whether or not the engine is running the plastic impeller blades are exposed to coolant.

The metal impeller blades may not fail, BUT if you have a pump bearing failure the impeller "machines" the aluminum housing away and destroys the engine. Water pumps are cheap and easy to replace.

ivangene

I agree with Jake and I know people who have changed water pumps before they go bad.... I call them smart - James for one

rwflier

My 996 3.4l had a water pump impeller failure, the little plastic impeller pieces clogged a passage in the 1-3 cylinder head, overheated and cracked the head.

Change the water pump! And I for sure am going to a metal impeller.

philooo

what are the reference for metal impeller ? is it a porsche oem part ?

There is a good video on youtube showing how to change the pump.

I might try it myself, but I am still scared of the vaccum system porsche recommend to refill the coolant system. Apparently the 'burping valve' on top of the coolant tank might not be able to really remove all air pocket from the system. Forum post suggest it could create air pocket/hot spots and also create problems. I wonder how much the dealer will charge me for a coolant flush.

No HTwo O

Change the pump when you change your serp. belt.

logray

The dealer will charge you gobs. Dealing with anti freeze sucks, it is sooooo caustic.

I've read from several sources the latest Porsche OEM water pump has a metal or "metal like" impeller.

If you have a 5 gallon or larger compressor, an equivalent vacuum refill system such as the one from uview 55000 is one of the best tools I own. It really isn't that hard to refill. Getting all the old coolant out on the other hand... sucks!

Yes I've heard of the air pockets too, which is why I chose to fork out the $100 for a uview 55000.

philooo

I don't own a compressor but considering that the dealer will charge me $500 for the job, that might take care of buying all the tools needed

I have read also that flushing the system takes a lot of work opening a bunch of different purge hose and screws. That's why I am still hesitant.

dotframe

Can someone who has done a DIY water pump replacement chime in? I thought it was supposed to be a pretty easy procedure?

Barn996

If you Go to youtube and type in 996 Porsche water pump replacement...there is a great video(mentioned) so you can decide if that's a job you want to tackle. GL

dennis hiip

Thanks for all the input! I went ahead and ordered the water pump at Sunset Porsche and was told that Porsche now recommends the 997 pump for the 996. It costs less too. How cool is that?

Barn996

Would you share the part #, and is that w/ plastic impellers or metal? Thanks

dennis hiip

997 water pump# 99710601102. I don't know if it's the older plastic impeller or the newer " metal like" plastic impeller but assume it's the latter. I didn't think the OEM pumps have metal impellers. Beck-Arney pumps have metal impellers and are about $100 at Rock Auto. I took Jake's advice and avoided that one.