ACDelco Professional 252-994 Engine Water Pump

Water pump replacements are never fun in general, but the Duramax is particularly bad because the water pump is ran off the timing gears, with a stud hidden right behind the harmonic balancer. So have the right tools or be prepared for a fight. I put this on a 2005 LLY Duramax.Must haves: Leslie flywheel lock tool, AT LEAST 5 ft breaker bar (can use cheater/extended pipe) with 3/4" drive, a 12 point 36mm socket w/ 3/4" drive (try not to use adapters-can if necessary), and an exact-o/razor blade to clean old gasket off of inlet flange. Make sure the breaker bar is heavy duty, I broke one during this job and I know I'm not the only one.Important notes:This is a messy job. If coolant gets on the serpentine belt (or subsequentially one of the pulleys which then gets on the belt), be prepared for an annoying belt squeal. Best to remove belt before draining coolant and clean the pulleys after completing the job.Make sure to fully clean off the old gasket from the inlet flange. If you leave old gasket residue where the inlet connects, the new seal will be compromised and you will have a leak.From the thermostat housing there is a coolant bypass pipe that leads into it from the water pump. It's very likely you will break that o-ring removing this piece. When I took it out it came with two backup rings and a main oring, but this replacement only has one oring. I ended up getting an oring from the chevy dealership instead and leaving one backup ring on. GM PN: 94011602.Check for leaks before putting fan shroud back on by turning truck on after adding coolant of course. I like to run water through it while checking for leaks, then flushing and adding coolant. It's an expensive mistake filling this beast up with coolant and then noticing a leak that requires you to flush all of the coolant to fix.

75.00 cheaper than oreilly's reman.Delivered on a Sunday morning at 9 am 16 hours after order

The origin of this product was not as stated. Was shipped from the USA, but was stamped CHINA. If you don't care, save $80 and buy the Gates. Other than deceitful in presentation and over charging, it's a working product.

The only thing I could pull a star for is the fact that the O-ring for the coolant bypass tube top end (where it goes into the t-stat housing) is slightly too large in diameter. Wall thickness is great, but the o-ring is just loose enough to roll out of place upon installation. A slightly smaller 0-ring with the same wall thickness, courtesy of the local hardware store, solved the problem. In and out in 4 hours, plus taking it all apart twice more to mess with the stupidly oversized oring. Do yourself a favor and get the properly (under)sized o-ring before you start the job.Oh, and here's hoping that AC Delco has figured out how to keep the pump shaft stuck to the impeller and drive gear. The press on fit that was in use last time I replaced the pump (110,000 miles ago) spun loose and wouldn't move coolant anymore.

This is a AC Delco (new) water pump. Only thing wrong is you will have NO bolt's . If you have trouble trying to get the old ones out to reuse you are in for a bad experience trying to find the two STUD BOLTS.. Three stars are for no bolts included for the price is not cool and I thought I was getting an American made product… surprise..

Overall nice product. One of the O-rings broke as I was putting it together. I replaced one small O-ring and the product has worked great for about 700 miles so far.

Can be a pain to replace yourself but well worth the savings over the dealership price

Had mechanic install with a new radiator in our 2005 GMC 1 ton dually and its running back at normal temperature even while hauling. Took it to North Carolina from Texas this summer and back hauling our 40 ft fifth wheel and temps stayed low.