: Water pump pulley disintegrating



David Jenison
08-26-08, 10:36 PM
1997 Concours water pump pulley is looking as if it is melting and clumps of the material are being found in the surrounding area. Even being lodged in between the water pump belt and the tensioner. This explains the squeeking this past week. Now the tensioner pulley has a flat spot worn in it.
Is this part failure common? Or should I just chalk it up to the age of the vehicle?

DAVE
'97 Concours

tateos
08-26-08, 10:46 PM
You mean the drive pulley - the one on the camshaft? That one is plastic - I guess it disintegrate, but I sure never heard of it. The one on the pump itself is metal, I think

Ranger
08-27-08, 12:09 PM
Check your pulley's. Sounds like one of the bearings is seizing and causing the belt to slip, thus melting the plastic pulley.

David Jenison
08-27-08, 12:09 PM
Yes. I do mean the drive pulley. It just seems odd that it would do something like this. I would understand if it cracked, but not just come apart in chunks.

DAVE
'97 Concours

Submariner409
08-27-08, 01:16 PM
Sounds like the tensioner idler seized, causing the belt to radically overheat from sliding over the flat pulley, thus melting the plastic w/p drive pulley. The whole thing needs to be disassembled, parts replaced, and test the w/p pulley for slop or grainy feeling when spun. You may have to cut the plastic drive pulley off the cam end (careful....) with a Dremel tool if it's been that hot............

tateos
08-27-08, 02:58 PM
sub - I think the plastic pulley has a metal hub, if I remember correctly

Submariner409
08-27-08, 04:46 PM
:yeah:.............Mine has a metal hub and is held by a round head Torx bolt.

Just doing the CYA routine and setting the OP up for a bit more than a standard belt change.....:sneaky:

tateos
08-27-08, 05:54 PM
What does the Torx head bolt do? Mine is pressed onto the camshaft stub

Submariner409
08-27-08, 07:19 PM
Good ol' GM.....tateos, take a look at the end of the w/p pulley/camshaft. Is there a threaded hole ? My '02 pulley has a metal hub with a puller groove machined in, and the whole hub is trimmed with a black round head #40 Torx bolt. Probably just a trim piece. Click in and look at the pic closely.........

jeffrsmith
08-27-08, 08:20 PM
Sub is right. There is a threaded hole in the end of the cam, that hole is there so you can thread in a jack screw to pull the pulley off. The machined groove is the same on most standard power steering pump pulleys. I used a power steering pump pulley puller to get mine off.

Ranger
08-27-08, 08:40 PM
The internal thread on the shaft is also used to press the pulley back on the shaft. That torx head cap screw is probably there just to keep the threads clean would be my guess.

Submariner409
08-27-08, 09:56 PM
:thumbsup: I pulled the Torx bolt. The underside of the head is concave and it and the threads are full of grease. (and the "bolt" is plastic.)

tateos
08-28-08, 02:21 PM
Very cool discovery, sub. My '97 pulley had no such cap, and the threads were clean - I live in the desert - Phoenix - so nothing ever gets very rusty here.

David Jenison
08-28-08, 03:28 PM
It was the tension pulley that seized up, overheated the belt and that is what caused the cam shaft pulley for the water pump to melt apart.
It's funny I did not hear anything out of the ordinary.

I hope everyone adds this problem to their list of things to look at on their northstar.

DAVE
'97 Concours

Ranger
08-28-08, 06:12 PM
I too am very surprised that the belt was not screaming for help.

tommyj
12-25-08, 12:02 PM
what size bolt would you use to pull the pulley banck on the cam shaft

Submariner409
12-25-08, 03:00 PM
Check your other post on the same subject.......

97EldoCoupe
12-26-08, 10:41 AM
M8 x 1.25 bolt. Metric. Any one of the exhaust manifold-to-cylinder head bolts will thread right in.

Cnjmale
01-27-09, 07:06 PM
Just had the same thing happen to my 00 Deville today with no warning, water pump spins freely as does tension idler, but i suspect the idler might had possibly locked or something, my water pump was just changed about 5 months ago. The pulley melted into a ball. oops.....