I've been doing this with 2gens for years and no issues...capping those passages is fine.


THe vacuum caps along will not hold for more than a few weeks as suggested. I have been using ultra black rtv in conjunction with them and this seems to work out just fine. Ultra black is the high temp stuff that dries relatively hard, and holds up well (I use it for coolant seals internally as well) to heat and coolant.

With the coolant drained, and the nipple being completely dry, I inject some of the RTV down into the nipple..roughly enough to penetrate to the bottom of it, where it joins the water jacket. Do the same for the one up front. Now, put a little bit of rtv in the cap as well, then slide it on and clamp it. Give it a few hours to dry before refilling coolant. This won't last forever, but it will up the time between cap changes to a year or more...I've YET to have one fail this way.

 

I typically use a short piece of hose with a bolt and two hose clamps. I've YET to have that fail, although it looks ghetto . But, I'd rather have something slightly ghetto in a place where you can't see it than water leaking out!

The nipple on the water pump housing can be cut off, tapped, and plugged with a pipe plug. On my '88, I actually used that hole for the temp sender for my Greddy water temp gauge - turned out real nice.

Dale