Water Pump Coolant Leak

[keystone]

Greetings

I have a 2000 GMC Sierra 1500 2WD 4.8 L 78,000 mi with a coolant leak that appears to be coming from the water pump gaskets where they bolt on to the block. I have read several posts on the forum and I still have a few questions that I need help with.

1.) Should I change the water pump and thermostat while I am there?

2.) Should I use GM (252-782) or aftermarket pump?

3.) Should I use Fel Pro (35635)or GM (251-663) gaskets?

4.) What temperature thermostat is best for just normal driving and will a lower temp ( 195 or 180) one cause any problems?

5.) Is Dexcool still the best choice?

 

Wow !! Sorry for so many questions and thanks in advance for your help !!

[txab]

Go ahead and change the pump. A quick look online it doesn't seem there is much if any difference on price between AC D pump and some aftermarket. Go with ACD. Gasket should be included with pump. Stay with the stock 'stat. Shows to be 186 degrees. That's what your computer is expecting to be in there and your engine will perform as it should. Dexcool question.... Opinions vary. If it has Dex in it now and is in good shape, then I'd stick with using a fresh fill of it, IMO. If it has green then put green back in. If you switch from Dex to green, it is my understanding you need to thoroughly flush all the old dex out.

[C & A s Dad]

I agree completely with what Txab has said. There are some good New Aftermarket pumps avail but not all New pumps are OE equivalent. I would suggest the AC or a an Airtex by ASC. We have been been selling Airtex new pumps for years and they are of a very high quality and match OE in form, fit and function. Just be sure the gasket you use is an O'Ring seal type gasket and not just a plain paper gasket. That was the issue with the OE gasket before GM redesigned it.

 

 

I would stongly suggest you stay with Dexcool if that is what is in there.

[keystone]

I agree completely with what Txab has said. There are some good New Aftermarket pumps avail but not all New pumps are OE equivalent. I would suggest the AC or a an Airtex by ASC. We have been been selling Airtex new pumps for years and they are of a very high quality and match OE in form, fit and function. Just be sure the gasket you use is an O'Ring seal type gasket and not just a plain paper gasket. That was the issue with the OE gasket before GM redesigned it.

 

 

I would stongly suggest you stay with Dexcool if that is what is in there.

 

Thanks so much for your help. I agree with your assessments

[Spurshot]

I replaced my waterpump on my 99 2500 6.0 this last fall. It had 210,000 miles on it. It had not failed nor was it leaking or making noise. I was just doing to preempt a failure on a long road trip. Because the original went 210,000 miles, I went with a OEM part (from the internet) which comes with the gaskets. I also replaced the thermostat and it's housing. I've run Dexcool in the truck since new and had replaced/flushed it only once at about 50,000 miles.

[keystone]

I agree completely with what Txab has said. There are some good New Aftermarket pumps avail but not all New pumps are OE equivalent. I would suggest the AC or a an Airtex by ASC. We have been been selling Airtex new pumps for years and they are of a very high quality and match OE in form, fit and function. Just be sure the gasket you use is an O'Ring seal type gasket and not just a plain paper gasket. That was the issue with the OE gasket before GM redesigned it.

 

 

I would stongly suggest you stay with Dexcool if that is what is in there.

 

 

Checked today with GM dealer. They now carry a pump assembly that includes thermostat, housing pulley and gaskets 251-714 for $179. Looks like a nice deal. Anyone have any experience with this one ? Original pump is 252-782. for $141. Must buy thermostat etc separate.

Thanks

Keystone

[Spurshot]

I believe that first "all inclusive" kit is the one I got for my truck. I unknowingly also bought the separate thermostat housing/thermostat/gasket kit. That's the way to go. Yes, I'd change the pump and thermostat . That price sounds pretty good compared to internet prices.

[txab]

I agree completely with what Txab has said. There are some good New Aftermarket pumps avail but not all New pumps are OE equivalent. I would suggest the AC or a an Airtex by ASC. We have been been selling Airtex new pumps for years and they are of a very high quality and match OE in form, fit and function. Just be sure the gasket you use is an O'Ring seal type gasket and not just a plain paper gasket. That was the issue with the OE gasket before GM redesigned it.

 

 

I would stongly suggest you stay with Dexcool if that is what is in there.

 

 

Checked today with GM dealer. They now carry a pump assembly that includes thermostat, housing pulley and gaskets 251-714 for $179. Looks like a nice deal. Anyone have any experience with this one ? Original pump is 252-782. for $141. Must buy thermostat etc separate.

Thanks

Keystone

 

You might want to check around for the ACD pump, better prices can be had, I think. Check out Rockauto.com. Looks they have the parts and you might save a few $$. I've used them before and am pleased with them.

[keystone]

I agree completely with what Txab has said. There are some good New Aftermarket pumps avail but not all New pumps are OE equivalent. I would suggest the AC or a an Airtex by ASC. We have been been selling Airtex new pumps for years and they are of a very high quality and match OE in form, fit and function. Just be sure the gasket you use is an O'Ring seal type gasket and not just a plain paper gasket. That was the issue with the OE gasket before GM redesigned it.

 

 

I would stongly suggest you stay with Dexcool if that is what is in there.

 

 

Checked today with GM dealer. They now carry a pump assembly that includes thermostat, housing pulley and gaskets 251-714 for $179. Looks like a nice deal. Anyone have any experience with this one ? Original pump is 252-782. for $141. Must buy thermostat etc separate.

Thanks

Keystone

 

You might want to check around for the ACD pump, better prices can be had, I think. Check out Rockauto.com. Looks they have the parts and you might save a few $$. I've used them before and am pleased with them.

 

 

Any idea what size the nut (socket size) is that holds the fan on to the pump?

Thanks

Keystone

[Spurshot]

Any idea what size the nut (socket size) is that holds the fan on to the pump?

Thanks

Keystone

 

1.425" (36.25 mm) is the nut size on the fan clutch as measured with a set of Starrett dial calipers. That's either a slightly loose 1 7/16" wrench or a very loose 37 mm.

 

I used a very large 18" crescent wrench and a mallet to beat on the end of the wrench to break it loose. I recommend doing this after the top schroud is removed and before removing the pump from the block while leaving the belt on for the extra drag.

[keystone]

Any idea what size the nut (socket size) is that holds the fan on to the pump?

Thanks

Keystone

 

1.425" (36.25 mm) is the nut size on the fan clutch as measured with a set of Starrett dial calipers. That's either a slightly loose 1 7/16" wrench or a very loose 37 mm.

 

I used a very large 18" crescent wrench and a mallet to beat on the end of the wrench to break it loose. I recommend doing this after the top schroud is removed and before removing the pump from the block while leaving the belt on for the extra drag.

 

 

Thanks Maybe a 36mm socket will work. I will check and post the result.

[Spurshot]

Any idea what size the nut (socket size) is that holds the fan on to the pump?

Thanks

Keystone

 

1.425" (36.25 mm) is the nut size on the fan clutch as measured with a set of Starrett dial calipers. That's either a slightly loose 1 7/16" wrench or a very loose 37 mm.

 

I used a very large 18" crescent wrench and a mallet to beat on the end of the wrench to break it loose. I recommend doing this after the top schroud is removed and before removing the pump from the block while leaving the belt on for the extra drag.

 

 

Thanks Maybe a 36mm socket will work. I will check and post the result.

 

 

Sorry,

I measured my 6.0L '99 truck. It has a different fan clutch (I know because the dealer gave me one for your eng once). However, I think the waterpump may be the same and the nut is likely the same size, but no guarantee. You can't use a socket. It has to be an open end wrench, as it is behind the clutch.

[Schmids5.3l]

Don't forget the water pump has 2 gaskets. (They are the same gasket).

[keystone]

Don't forget the water pump has 2 gaskets. (They are the same gasket).

 

 

Thanks. Yes they both came in the ACD box with the pump.

[pdtech]

Don't forget the water pump has 2 gaskets. (They are the same gasket).

 

 

Thanks. Yes they both came in the ACD box with the pump.

 

 

 

gm gaskets looks better than felpro-its redesigned so the oring wont slip out of place-