Boxster 986 2.7 Water pumps

[justinbaker]

Hello all, enjoying the car lots, and its being a great commuter car too. A couple of days ago, when in traffic a while, the drive-belt started to squeal, so suspect the water pump may be on its last legs. Its been making a grumble from there for a while. Its parked up in my garage and will attempt to get round to ordering a replacement. My question is, are there poor quality items about, or should I just order one of Porscheshops?

Or can anyone recommend a good place for what looks like a common item. Shall I change the belt too?

BTW: The temperature didn't read overly hot 85 or so, and the oil light flickered at idle, so suspect it was getting hot, I am wondering if the thermostat is screwed?

[Rockster]

justinbaker said:

Hello all, enjoying the car lots, and its being a great commuter car too. A couple of days ago, when in traffic a while, the drive-belt started to squeal, so suspect the water pump may be on its last legs. Its been making a grumble from there for a while. Its parked up in my garage and will attempt to get round to ordering a replacement. My question is, are there poor quality items about, or should I just order one of Porscheshops?

Or can anyone recommend a good place for what looks like a common item. Shall I change the belt too?

BTW: The temperature didn't read overly hot 85 or so, and the oil light flickered at idle, so suspect it was getting hot, I am wondering if the thermostat is screwed?

Sorry, but I got interrupted and had to post before I was finished...so some of the stuff below has been changed or added to from my first posting...

There are probably poor quality water pumps around.

Some believe the Porsche water pump is poor quality because of its plastic impeller.

Maybe.

All I know is the water pump in my 02 2.7l engine lasted over 170K miles and the impeller was fine.

As an aside the impeller might have failed had I tried to nurse the car along with a bad water pump. As the pump's bearing deteriorated they could have allowed the impeller to flop about and while the plastic is tough it can't stand that kind of abuse for long. Another possible cause of impeller failure is if the cooling system runs low on coolant or lacks the ability to maintain sufficient pressure. The pump impeller blades may experience cavitation and this can destroy water pump impeller blades.

Anyhow, because the OEM/factory water pump delivered such good service I saw no reason to stray to a 3rd party pump so I had another factory pump installed along with a new t-stat.

Another aside: I like to test a new t-stat (along with the old one) by dropping both in a pot of hot water and watching the t-stats to ensure both open at their operating temperature. A new t-stat may be bad or even mislabeled and the time to know this is before it is installed not after.

I might add that I examined the old water pump and its impeller quite carefully and I spotted signs the impeller blade edges appeared to have rubbed against the casting of the water pump enclosure. Now some might feel this is from poor manufacturing but it can be done on purpose. The blades are slightly bigger than they need to be and upon first being used they abrade themselves to very tightly fit in the working space to help maximize the efficiency of the water pump.

Just a thought...

Anyhow, if the water pump comes out of your car with a busted impeller then the possibility exists the pump impeller fragments are somplace: in the engine coolant passages, in the radiators, someplace (though they may have been busted up into small enough pieces that they come out with the coolant... it is important to when the old coolant is drained to catch it in a clean drain pan and check it for pieces of impeller). If some impeller material is unaccounted for and is still in the engine or cooling system it can interfere with the proper flow of coolant through the engine.

A strong back flushing of the cooling system is called for in the hopes this will flush out any impeller pieces. Ideally the flushing fluid (water) wants to be caught and like the orignal coolant checked for any impeller debris.

Almost certainly the belt needs to be replaced. In my car's case one of the first clues I had that something was amiss was a rather new belt had developed a sharp edge (the inner edge) which is a sign the belt is not tracking properly. The old belt while of course old didn't have any sharp edges, so the cause of the mistracking appeared after the belt change.

If in your car's case the belt has no sharp edges and is otherwise in good condition you can reuse it. Be sure you note the belt's direction of rotation so you install it in the same direction.

As for the T-stat it may be bad. Rare but it happens. I covered t-stats above some but let me add this: I can't recall a time I've changed a water pump or had one changed that I didn't replace or have replaced the T-stat at the same time.

The only thing -- and I repeat this because it is important -- is to test the t-stat to ensure it works properly and opens at the specified temperature. Now if you have this work done the t-stat will be covered by a warranty but a flaky t-stat can be a pain to diagnose and my belief is better to identify a flaky t-stat before installation rather than after.

Sincerely,

Rockster.

Edited by Rockster on Wednesday 28th September 21:54