97Z28Muscle

Just installed a brand new GM water pump a little over a month ago. Hasn't leaked a drop with the brand new bolts and automotive white teflon liquid sealer. Fire her up this morning and here we go again, leaking from at least the top two bolts. I guess the thread sealer i'm using is garbage. Are you guys using black RTV or something else? Any suggestions are greatly appreciated.

Injuneer

RTV doesn't sound like a good choice. Why not a compound specifically made for sealing threads in blocks, like the ones made by Permatex or ARP? They contain PTFE.

97Z28Muscle

Fred-That's exactly what i'm using, the thread sealer that contains PTFE. It has held for a month but is now leaking pretty bad from those top two bolt holes. I got some new copper washers and some coppercoat that i'm gonna use and try sealing off the heads of the bolts along with more ptfe on the threads.

shoebox

Are you cleaning the bolts and holes, first? Are you tightening them to spec? Are the bolt threads in good shape? The Permatex thread sealant works well for me and I have even installed the water pump bolts before without sealer and had no leaks.

97Z28Muscle

Yes, the holes are clean and the bolts are new. I am using the recommended sealer and torqueing to specs in the manual. I am not using GM bolts, I'm using grade 8 bolts the correct length. I also put brass washeras under the heads and it didn't leak for a month. I have been watching very closely everywhere I go and checking for leaks...nothing visible. I started the car to let it warm up and less than 5 minutes later there is about 2 ounces of coolant on the floor. Any more ideas? Are the GM bolts something special? They are $15 a pop.

RamAir95TA

Is the coolant leaking out between the water pump and the block? Or the bolt heads (on the pump away from the block)?

If you are torquing them properly with thread sealant on the threads, there has to be some corrosion or crack in either the front of the block, the threads are marred, or you aren't using enough RTV/sealant on the WP gaskets themselves (causing coolant to run down the bolts through the WP and out the heads).

97Z28Muscle

Hey Joe. The coolant is leaking from the heads of the bolts. I used permatex ultra black RTV on both sides of the water pump gaskets, and I know it sealed good because it has not leaked a drop in a month. The bolts were deteriorated, maybe the block has just enough corrosion in the threads to let some water by. I'm baffled as to why it would just start leaking. If you pop the hood and look down at the water pump, you can clearly see coolant on the top two bolt holes, right at the heads of the bolts.

mad95z

You said the bolts are deteriorated get new bolts, make sure they are the proper size/thread.

my1994z28

Same here I use the Permatex sealant with teflon,and no leaks..I would remove the water pump,clean it up real good and look at the area of the top bolt holes.Possible you may have a fine line crack in it.Also Permatex makes sealant for water pump gaskets..Its a small tube that costs about 4.00..but it works.Try using that on your gaskets.

97Z28Muscle

I think you misunderstood me. I already replaced the bolts with brand new ones, the correct length and thread. I guess i'll be pulling the pump off again to see if it is cracked somewhere.

bw_hunter

When you reassemble, don't use RTV on the paper gaskets. Regular gasket adhesive like a Permatex #2 or Copper. You'll get better results.....

97Z28Muscle

Ok I got her fixed now, I think for good. I removed each of the four bolts one at a time. The permatex teflon thread sealer with PTFE was pretty much washed away on the first 3/4" of the threads. Somehow the coolant was washing away the thread sealer and leaking through the heads. I ended up cleaning the bolts and using regular teflon tape. Then I used new copper washers on the heads and some copper coat on the heads/washers. It isn't leaking anymore, but i'm gonna keep a close eye on it. I think the teflon tape is actually better than the thread sealer. It is way more solid and rated for steam so it will be fine.

97Z28Muscle

The RTV on the paper gaskets is not leaking. If I ever do take off the water pump, i'll be re-installing it with copper coat and paper gaskets.

WS6T3RROR

Use permatex 518 (sometimes labeled 51813) for the bolts. This works perfectly for this type of job. I use it for head bolts and especially head studs and have yet to have a problem. In a pinch 'the right stuff' can be used on the water pump bolts if you can stand to wait for it to cure.

ACE1252

Permatex High Temperature(not high performance) thread sealant is what you need.
http://www.permatex.com/products/aut...ad_Sealant.htm


I have used it dozens of times with no leaks. Head bolts, water pump bolts, knock sensor, oil fittings....etc. I do assemble the parts clean(thread chaser) and dry. I also give it overnight to cure. I use a generous amount on all the threads.....almost to the point of being too much, but the formula works.

As recommended above, a thin coating of permatex #2 on the water pump gaskets(and all paper type gaskets) is helpful in sealing them. I coat both sides of the water pump gaskets with a thin coat.

Make sure you get surfaces clean too. That can be a pain with the gasket cement GM used to hold the gaskets in place....some dang hard stuff. Lacquer thinner and a razor blade helped me quite a bit. You just have to be careful not to gouge the surfaces with the corners of the razor blade.