Where does the accounting department enter the equation?

 

....

 

Replaced the water pump 18 months ago.

Just replaced it again this week because of a leak.

 

When the water pump becomes suspect, does it make any telltale sounds? Just wondering if there is something to listen for.

 

^^ in my case coolant on the garage floor.

 

In a prior issue of Excellence Mag many months back... they had an article which indicated that the WP should be considered for replacement every 40K-50K miles.

 

Hey USMC_DS1, was your replacement WP a composite impeller type? Where did you order it?


Really interesting thread. I have 29K on my 06 and will replace the WP in the Spring.

 

Cvtbenhogan, I ordered it from sun coast but it's also available from pelican. It has the polymer impeller. I avoided the metal impeller (not sure it's available either) as a mis-alignment of the metal impeller shaft could deform the wp chamber.

 

when water pump starts to leak you will see very telling red residue on its bottom and sides. it is impossible to miss. if it is dry and looks fine then do not worry

 

But are there visible clues when there is impeller erosion?

 

Yes, and no.

Yes in the case of my Boxster. It was a low rumbling noise that prompted me to look into the source and eventually identify the water pump.

However, no in the case of my Turbo. There was no noise.

There was an uncharacteristic rise in coolant temperature driving slowly in a parking lot on a warm day. The temp gage needle climbed several needle widths higher than it had ever gone before. I also caught a whiff of anti-freeze.

At the dealer the tech took a look. The driver's side radiator fan was not running while the passenger side was blowing like a blast furnace.

The coolant level was ok, there was no coolant leak sign under the car.

The tech offered the opinion the T-Stat may have quit working but on the lift the next day the tech managed to spot leak sign at the water pump. A nice deposit of dried antifreeze residue had collected.

So we decided to replace the water pump, the T-stat (keeping with the factory one that opens at 83C), and replace the driver's side radiator fan motor.

My point is you may not get a noise for a warning. In the case of my Turbo the temp gage needle venturing into territory into which it never ventured before along with a whiff of antifreeze had me get the car in for a pro's opinion. (As an aside, the Turbo water temp gage needle barely goes a fraction of a needle's width past the "180" hash mark.) Had I waited for noise the water pump may have failed catastrophically with serious damage to the engine. As it was the only damage, so to speak, was to my wallet, which compared to what it could have been is of no real consequence.

So you can listen, to be sure, but you can't rely upon noise alone for a warning the water pump is going out, nor can you rely on the absence of noise as evidence there's nothing wrong.

What can you do? Use all your senses, and rely on the car's gages

Keep an eye out for leaks. Check the coolant level once in awhile. Out of habit I glance under the car when I walk up to it looking for any leak sign under the car. Pay attention to the gages when the car is healthy to know possibly when it is not healthy. And use your nose. A smell of anti-freeze is reason to suspect a coolant leak even if there are no other signs of one.

 

Thanks USMC_DS1.

BTW. I'm doing a timing belt on my Audi and the replacement parts includes a WP with metal impeller. No worries as the car is older.

 

Macster, I was thinking a stethoscope now and then might be useful for the WP.

 

Sure thing CVT. I had an M3 previously and we debated the merits of the metal vs. polymer impeller... it's a matter of selecting a risk factor. When a polymer impeller breaks apart bits of the impeller could get logged somewhere within the coolant system which could potentially require removal of all coolant lines to get the bits. If the bits lodge themselves within the engine block then things get much more complicated and hots spots may occur resulting in a cracked engine block. The metal impeller have the risk of the bearing wear which may result in mis-alignment of the impeller shaft and it's blades which would lathe/deform the WP cavity resulting in poor coolant and potentially an over heated engine... plus once the damage is done it would require a new engine block. To address/minimize these risks I've elected to continue use of Porsche's WP(with polymer impeller) but RR the WP as part of my scheduled maintenance every 40K miles.

 

Last summer, couple of drops on the garage floor. thought it was just air conditioning condensation drippings. "Low coolant level" light came on in the dash.
What does that mean? I wonderland in my head. Low? as an inch low? or Low? Like none? A block away from home, turned around and parked it in the garage. Just as it puked more coolant on my garage floor. Replaced the pump and the and the cracked coolant reservoir, and a new belt while I was at it. The pump upon removal, had a few of the fins missing.
Thinking of putting a spare pump, gasket and belt in the frunk for a spare on long road trips. My rule is, you never need a spare, when you have one.