5.3 Water Pump Gaskets

[Jet-X]

My 2002 has started to leak on the passenger side water pump gasket.  So, I decided to replace the water pump with a new AC Delco #252845.  This unit comes with new silicon lined gaskets.  I don't know if these are still from the original design or not.  I also noticed that AC Delco has made a change to the gasket sealing surface on their standalone gaskets #251663, hopefully more robust to improve the seal.  The question I have is which gasket is preferred?  I've attached a side by side comparison.  I don't want to do this job more than once.  Lastly, should the gaskets be installed dry, or should the mating surfaces be skim coated with RTV?   Thanks

[slothy]

i just did my 07.5 with the ac delco ones (came with pump)  like you posted and no leaks.

[txab]

You will be fine. The pump you bought still has the upgraded gaskets. AC Delco sells two lines of water pumps. The one you purchased is the aftermarket line that is sold through many parts stores. The other is their OE line that is sold through dealerships and is made in Canada, the last time I purchased one.

[Mike GMC]

Put the gaskets on dry.  At least that's what I did and have no leaks.  Just make sure the mating surfaces are spotless.

[carnau]

On 3/4/2018 at 10:15 AM, Jet-X said:

My 2002 has started to leak on the passenger side water pump gasket.  So, I decided to replace the water pump with a new AC Delco #252845.  This unit comes with new silicon lined gaskets.  I don't know if these are still from the original design or not.  I also noticed that AC Delco has made a change to the gasket sealing surface on their standalone gaskets #251663, hopefully more robust to improve the seal.  The question I have is which gasket is preferred?  I've attached a side by side comparison.  I don't want to do this job more than once.  Lastly, should the gaskets be installed dry, or should the mating surfaces be skim coated with RTV?   Thanks

Personally I like the AC Delco gaskets. I always throw the junk paper gaskets away and if the metal gaskets are not a good sturdy quality material I throw them away as well. 

 

When I do this I always take a piece of fine sand paper and clean the block. Then I clean it with brake cleen, dry it off really good and use a little bit of gasket maker with the seals. That's just what I do, but I don't want to be doing the job a second time. 

 

7$ GM Water pump gasket - http://amzn.to/2oNvqN9

7$ Brake Cleen - http://amzn.to/2HaJTtw

6$ High Temp Gasket Maker - http://amzn.to/2G4BsAN

[PTXer]

Chris, as I said I work for Permatex.  The red gasket maker is older technology best used on exhaust manifolds as it has a high temperature resistance.  The Ultra Grey is much more resistant to coolant.  Its the only thing I would use on water pumps. 

 

Grey Gasket Maker

[Jet-X]

Thanks everyone for the inputs.  The pump arrived and I didn't care for the quality of those stock metal gaskets.  I picked up the AC Delco parts as you suggested carnau.  I agree, the prep is the key for a long lasting seal.  The instructions specify no sealant. I'm used to adding a skim coat to most gaskets just for piece of mind, but this time I'll install them dry and see how it goes.