Paper gasket or silicone for water pump? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

PatrickGMC70 · 08-04-2013, 12:23 PM

I'm in the process of tracking down a S - L - O - W coolant leak on my truck. Everything is new, which is why this is particularly frustrating. Long sorry short, I was getting tired of the drain, fix, refill, still leaking approach, so the water pump is now off. (I'd thought it may have been a slow leak from the back cover of the pump.)

In mounting the pump back to the block, I have a set of the paper/cardboard gaskets, and which I used originally. But I was wondering if these are a weak link, or if they're a tried and true way of sealing this spot. So before I threw it back together, I thought I'd ask whether there's a consensus about using the standard gaskets or gray silicone (or both). When I took the pump off, the gaskets were wet, but I'm assuming that was just from the process of taking it out and the coolant that was behind the pump.

The only good news is that after all of this, my problem should be solved (unless I put something back together wrong) because everything else has been checked and rechecked.

Thanks!

Patrick
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Andy4639 · 08-04-2013, 01:02 PM

My personal preference is use both. I coat both sides of the gasket's with sealer and install.

Now for the ? of the leak. Do u run a recovery tank? If not I suggest u start and if not then where is your water level at when the truck is cold? if it's to high in the radaitor then it will boil out and the cold level will be less the next time u check it.

vidman · 08-04-2013, 01:52 PM

I would use the gasket and a sealant. I have been using Edelbrocks gasgacinch for a while with great results..

Tx Firefighter · 08-04-2013, 03:45 PM

Paper gaskets with a little dab of Permatex #2 or Hondabond or similar glue is all you need.

There is no need for silicone under any circumstances. There's exactly two places to use silicone on a Chevy V8 engine, at the ends of the intake manifold and at the corners of the oil pan gaskets.

As long as you get the surfaces clean with a razor blade or gasket scraper and use proper torque procedures you will be fine.
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1972RedNeck · 08-04-2013, 03:51 PM

I don't use any water pump/timing cover/valve cover/oil pan (etc.) gaskets at all. It is all grey silicone.

PatrickGMC70 · 08-04-2013, 04:02 PM

Thanks everyone.

It really was a small slow leak - about 2-3 drops per min or so. It was coming from somewhere near the pump, and I'd already checked the lower radiator hose, heater hose, heater hose nipple, & even replaced and added sealer to the mounting bolts. Then in between each "fix" I had to wipe down everything - crossmember etc - to make sure it was still a leak and not just residue.

I'm sure taking the pump off wasn't the most logical or rational step, but I was just so disgusted and frustrated with this leak that it was halfway off before I knew it. Hopefully, this will be the last time for a very long time!
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PatrickGMC70 · 08-04-2013, 04:08 PM

Quote:

Originally Posted by Andy4639

My personal preference is use both. I coat both sides of the gasket's with sealer and install.

Now for the ? of the leak. Do u run a recovery tank? If not I suggest u start and if not then where is your water level at when the truck is cold? if it's to high in the radaitor then it will boil out and the cold level will be less the next time u check it.

Thanks. I don't have a recovery tank (yet) but it wasn't leaking at the drip hose. It was coming from the water pump in the front on the engine. BTW, it's pretty scarry sitting under a running truck with that fan spinning right above you looking for where the leak is coming from.

The recovery tank is definitely on my short list of projects to get done.
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Lee H · 08-04-2013, 04:46 PM

The lower right water pump bolt goes into the water jacket and needs sealed, or it will leak.

PatrickGMC70 · 08-04-2013, 04:50 PM

Thanks Lee - I wasn't taking any chances though. I put sealer on all 4 bolts. This leak will die!
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**Stocker** · 08-04-2013, 05:53 PM

Quote:

Originally Posted by Tx Firefighter

Paper gaskets with a little dab of Permatex #2 ...... is all you need.

x2..... no silicone, I've seen it leak too often.

GRX · 08-04-2013, 06:34 PM

Paper with a thin film of #2 or Aviation Permatex 'form a gasket'.

MLB57 · 08-04-2013, 08:17 PM

Use a anaerobic gasket maker. Will fill a .010 gap and will never leak, use your paper gasket it with it. I have mounted water pumps with no gasket and never had a problem

08-04-2013, 12:23 PM	#1
PatrickGMC70 Registered User Join Date: Jun 2010 Location: Parkville, MD Posts: 163	Paper gasket or silicone for water pump? I'm in the process of tracking down a S - L - O - W coolant leak on my truck. Everything is new, which is why this is particularly frustrating. Long sorry short, I was getting tired of the drain, fix, refill, still leaking approach, so the water pump is now off. (I'd thought it may have been a slow leak from the back cover of the pump.) In mounting the pump back to the block, I have a set of the paper/cardboard gaskets, and which I used originally. But I was wondering if these are a weak link, or if they're a tried and true way of sealing this spot. So before I threw it back together, I thought I'd ask whether there's a consensus about using the standard gaskets or gray silicone (or both). When I took the pump off, the gaskets were wet, but I'm assuming that was just from the process of taking it out and the coolant that was behind the pump. The only good news is that after all of this, my problem should be solved (unless I put something back together wrong) because everything else has been checked and rechecked. Thanks! Patrick Posted via Mobile Device

08-04-2013, 01:52 PM	#3
vidman Registered User Join Date: Jun 2012 Location: Fitchburg,Mass Posts: 737	Re: Paper gasket or silicone for water pump? I would use the gasket and a sealant. I have been using Edelbrocks gasgacinch for a while with great results.. __________________ 62 Willys 4wd Pickup : 72 C-10 swb 504 stroker 09 Taco 3" lift 33" tires: 90 K-5 blazer (plow truck): RIP Ross Little brother

08-04-2013, 03:45 PM	#4
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: Paper gasket or silicone for water pump? Paper gaskets with a little dab of Permatex #2 or Hondabond or similar glue is all you need. There is no need for silicone under any circumstances. There's exactly two places to use silicone on a Chevy V8 engine, at the ends of the intake manifold and at the corners of the oil pan gaskets. As long as you get the surfaces clean with a razor blade or gasket scraper and use proper torque procedures you will be fine. Posted via Mobile Device

08-04-2013, 04:02 PM	#6
PatrickGMC70 Registered User Join Date: Jun 2010 Location: Parkville, MD Posts: 163	Re: Paper gasket or silicone for water pump? Thanks everyone. It really was a small slow leak - about 2-3 drops per min or so. It was coming from somewhere near the pump, and I'd already checked the lower radiator hose, heater hose, heater hose nipple, & even replaced and added sealer to the mounting bolts. Then in between each "fix" I had to wipe down everything - crossmember etc - to make sure it was still a leak and not just residue. I'm sure taking the pump off wasn't the most logical or rational step, but I was just so disgusted and frustrated with this leak that it was halfway off before I knew it. Hopefully, this will be the last time for a very long time! Posted via Mobile Device

08-04-2013, 04:46 PM	#8
Lee H Registered User Join Date: Jun 2010 Location: Upland Ca Posts: 4,142	Re: Paper gasket or silicone for water pump? The lower right water pump bolt goes into the water jacket and needs sealed, or it will leak. __________________ 1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703

08-04-2013, 01:02 PM	#2
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,936	Re: Paper gasket or silicone for water pump? My personal preference is use both. I coat both sides of the gasket's with sealer and install. Now for the ? of the leak. Do u run a recovery tank? If not I suggest u start and if not then where is your water level at when the truck is cold? if it's to high in the radaitor then it will boil out and the cold level will be less the next time u check it. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

08-04-2013, 04:50 PM	#9
PatrickGMC70 Registered User Join Date: Jun 2010 Location: Parkville, MD Posts: 163	Re: Paper gasket or silicone for water pump? Thanks Lee - I wasn't taking any chances though. I put sealer on all 4 bolts. This leak will die! Posted via Mobile Device

08-04-2013, 06:34 PM	#11
GRX Registered User Join Date: Jul 2010 Location: MD Posts: 1,937	Re: Paper gasket or silicone for water pump? Paper with a thin film of #2 or Aviation Permatex 'form a gasket'. __________________ 1969 c-10 Step Side Long Bed. I-6 250cid = = 1969 Pontiac GTO hard top. 400, 4-speed.

08-04-2013, 08:17 PM	#12
MLB57 Registered User Join Date: Sep 2011 Location: olathe kansas Posts: 238	Re: Paper gasket or silicone for water pump? Use a anaerobic gasket maker. Will fill a .010 gap and will never leak, use your paper gasket it with it. I have mounted water pumps with no gasket and never had a problem



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