Help Needed 94.5 Coolant Leak - Rear Of Motor

[DaveBen]

Try the RTV and let it set up for a while before bolting back on. If you bolt it on after you use the RTV, it will mush out on you and not seal. I am glad you found it before you tore the entire engine apart.

Dave

 

[wils2527]

Yeah I second that about tearing the motor and tranny apart.

I used a little RTV around the edge last time, but I didn't want to "over-do-it" so to speak. I hate to ask for such technical advice, but is there an amount that I should do. A smooth layer? Also should I apply some RTV to the block? Or just to the water pump.

 

[DaveBen]

I just use my finger and put on an even coat of RTV to the pump about 16th of an inch thick. The key is to make it smooth and even thickness without humps that will leak. Let it set for an hour to three hours and then bolt it on. Good Luck Patrick.

Dave

 

[wils2527]

Ok sounds good. I will pull the pump back off on my day off on Friday and let the RTV setup for a few hours and then I bolt everything up to the block.

To be honest I never knew that you should RTV and let it sit before you bolt it up to the block. I would have thought that you RTV and place the pump in place and bolt up. That is definitely where I screwed up.

Thank you for your help Dave!

 

[DaveBen]

You betcha Patrick. We all learn tricks as time goes on.

Dave

 

[dpantazis]

umm, silly question.... didn't your pump have the big molded o-ring gasket?

this gasket fits into the groove on the housing. you dont need to slop it up with RTV to make it seal. the new pump should have come with it.

if the old one did not have one, but had the groove, someone before you f'd it up.

i'm just saying if its that troublesome, its probably not right.

 

[DaveBen]

Not so silly. I am no expert of the '94 Powerstrokes. Thanks dp!

Dave

 

[wils2527]

Hey dpantazis the original did not have a gasket (I'm now going to assume that is why it was leaking). The new one did come with a gasket but I have a theory about why it leaked.

I put RTV all over the gasket and then I know for a fact that the pump moved a bit when I was installing it. That being the case I'm almost certain that the gasket slid a little and provided me with the leaks.

So on Friday when I pull it off I might (assuming my camera is working) try and take some photos. I also heard that often times residue against the block there can cause havoc depending on what is left behind.

That being the case I heard I should use some sand paper and clean all of that up before I put on the new pump. I wish I would have read that before I did this last time. But being that there is RTV all over the place I am going to clean the surface a lot better this time.

 

[dpantazis]

Sometimes trying to make it better you actually make it worse.

No sealer in oring gaskets.

It probably leaked because the oring could not properly squish because of all the rtv.

 

[wils2527]

Ok that makes sense. I'll try it minus the RTV first. Then if I have problems go back and try and mess with the RTV.

Just kind of a general question; am I ok to pressure test all of this when I'm done installing the water pump? Or is there a sit and wait time before doing so?

The reason I ask is that I have a small crack in my radiator also (has been there for a long time just now leaking more and more) and I have a radiator shop that said they could get it back to me on Monday if I drop it off tomorrow.

I ask because if it is still leaking (minus using the RTV for the install) then I'd like to pull it off this weekend and get it ready for Monday when I get the radiator back.

Thank you again for all of your guy's help!