Author Topic: Water pump gasket blew. RTV to fix or source a gasket?  (Read 117 times)

Offline SUX2BU99

  • Senior Member
  • ****
  • Posts: 1478
    • My Cardomain Site. Truck is on Page 6.
Water pump gasket blew. RTV to fix or source a gasket?
« on: June 06, 2019, 05:12:54 PM »
I have a Weiand Action Plus aluminum water pump on my 350. The other day I took my truck out and when I got on it hard, I was told by a guy at the next light I was puking coolant all over the road. :o So I thought it was the water pump gasket to the block again, as I blew that a few years ago at the drag strip. After taking the pump off I see that the gasket at the back of the housing itself seemed to blow through as some of it was hanging out. I can remove this cover to get to the impeller but i"m not sure if I can actually buy this gasket. I have some Permatex red RTV. Should I remove the gasket and reseal it with the RTV or try to source the gasket?

I'm also going to have to obviously replace the other water pump gaskets and I might re-do my fuel pump too as I have an oil leak there. In reading about using gasket sealer to 'glue' on gaskets and also thread sealer on water pump and fuel pump bolts, I read that Permatex #2 works well for both. Thoughts? Normally I would use the RTV on the gaskets and Teflon tape on the bolts but I was reading that isn't such a good idea.

Thanks.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13041
  • Family is not an important thing. It's everything.
Re: Water pump gasket blew. RTV to fix or source a gasket?
« Reply #1 on: June 06, 2019, 06:31:51 PM »
i would go to the parts store and get a roll of gasket material and make it. they also sell sheets of it that would be cheaper than the roll but i keep some on hand for odd things
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline bd

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 5172
Re: Water pump gasket blew. RTV to fix or source a gasket?
« Reply #2 on: June 06, 2019, 07:50:36 PM »
You realize that ten different people will offer ten different repair strategies.  lol

Assuming a stock gasket configuration, use a Fel Pro 13032 (less than $2).

Did you check the tightness of the W/P plate bolts before you installed the pump?  It's a must!

Have you performed any failure analysis?  Are the plate and pump mounting bolts just backing out?  What about gasket quality?  What are you using for coolant?  Is the engine building too much cooling system pressure?  The outcome of an analysis will benefit your repair strategy.

That stated, I recommend using new gaskets coated with High Tack or Ultra Grey.  Or, you can substitute The Right Stuff Gasket Maker, but it is pricey for such a small repair.  Lightly reverse dimple the plate bolt holes using two ball peen hammers being careful to not warp the plate.  Wire wheel the bolts then chase the bolt holes using a bottoming tap.  Prime the male and female threads with starter fluid, Berrymans B12 or Loctite Klean 'N Prime.  After about 5 minutes, apply blue Loctite to the bolt threads then assemble and tighten immediately to ~80 in-lbs (~7 ft-lbs). 

Wire wheel the four W/P mounting bolts and chase the bolt holes in the block.  Thoroughly rinse the threads with Klean 'N Prime and blow them dry with compressed air, then coat the bolts with Permatex High Temperature Thread Sealant or ARP Thread Sealer with Teflon and reassemble with new W/P gaskets coated with Ultra Grey, tightening the bolts in three discrete steps.  Three steps help prevent the gaskets from being pinched differentially, which can increase the risk of subsequent leakage or possibly cracking the aluminum W/P flanges.  Once the W/P bolts are tight, don't disturb them.
Rich
It's difficult to know just how much you don't know, until you know it....
In other words... if people learn by making mistakes, by now I should know just about everything!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 17285
Re: Water pump gasket blew. RTV to fix or source a gasket?
« Reply #3 on: June 07, 2019, 04:45:22 AM »
Quote
you can substitute The Right Stuff Gasket Maker

Use the Right Stuff. You can buy the small easy cheese can and replace your radiator cap while you're at it but in my opinion it sounds like this water pump is not suited for you or even necessary. If this is the second time it let you down, I'd revert back to a stock pump.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

Offline SUX2BU99

  • Senior Member
  • ****
  • Posts: 1478
    • My Cardomain Site. Truck is on Page 6.
Re: Water pump gasket blew. RTV to fix or source a gasket?
« Reply #4 on: June 10, 2019, 11:10:30 AM »
Thanks for the replies. At the parts store (Lordco) they were able to give me a stock water pump impeller gasket and it worked perfect on the Weiand pump. I bought some Permatex #2 gasket sealer and used it instead of the high-temp RTV on all gaskets, including the water pump to block gaskets and also as a thread sealant instead of Teflon tape.

I also decided to reinstall my fuel pump and change the gasket too as it had been dripping oil since I changed it last a few years ago. I used the hacksaw blade trick to hold the pump rod up while installing the pump and it worked FANTASTIC! I used the #2 on the gasket and also the bolts.

As to the pump itself, I can't really say why it's blown out a gasket twice now when under WOT. I don't believe it to be some kind of super high volume or high pressure type of pump. I've made sure now to have the correct volume and water and coolant in the system. Perhaps I had some air in there, I'm not too sure. If I do have a problem a third time, I'll put a stock pump in.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.