bh5

Please help, I have a 87 renix cooling setup. Two Y pipes. I need help to figure out where they go. Hose from t.stat into y pipe, y pipe to ?upper or lower heater core and ?upper or lower resivor... then Hose from water pump to y pipe, then y pipe to ? upper or lower heater core and upper or lower resivor. Thank you for any help.

djb383

Cruiser should be by shortly to help.

cruiser54

This help?

bh5

Cruiser... is that thermostat hose to upper HC and upper reservoir, then pump hose to lowers?

DFlintstone

The top/inside hose goes to the valve. The outer/lower goes to the tee to the bottom on the expansion bottle and the heater...return. Might be if you did the bottom first, the upper would make more sense. Be careful with that valve plastic! It breaks easily.

cruiser54

Thermostat to lower HC. Water pump to upper HC.

And Flintstone is right about the heater valve. My advice is to eliminate it right now and replace it with a piece of tubing. Plug the vacuum line. I have a particular hate for those things. Not only are they unnecessary, they are dangerous in more than a few ways. They can just let go at the most inopportune moment and leave you stranded. Or, they can do what one did to me. I was reaching in to change the oil filter on a hot engine, brushed it with my forearm and it split wide open and sprayed hot coolant in my face. You don't forget that.

DFlintstone

S'never smart to disagree with Cruiser, but I don't want that 195* water circulating in my cab. My AC works today, but hasn't always. Well Cruiser, you were so Darn good looking before, consider the burn an improvement!

Anyway the OD of a 1/2 inch copper fitting seems to fit OK in the hose. Seems the 1/2 inch pipe it's-self is a little small, but the outside of an "L" (90*), or a coupling has been working for me.

5-90

My take on solving the problem...

Use 1/2" copper tube & unions. For the 3/4" ID hose, solder a 1/2" straight union on the end of the tube to bring the OD up to fit (1/2" copper tube is right about 5/8" OD, and the OD of a 1/2" union is a lot closer to 3/4" than the 1/2" tube...)

bh5

What do you think of putting an inline radiator cap and filler in the upper radiator hose, and getting rid of the y pipes and pressure tank all together? I have seen it done on others, just not sure about pros and cons of it.

cruiser54

All purchased at OSH on Branham Lane?

5-90

Yep - before Branham & Almaden got moved to Meridian & Blossom Hill...

DFlintstone

It's my take you need air-space for expansion when things get hot. (hence we never fill the expansion bottle more then about 1/2)(or something gives).

I see 5-90 has a valve.

5-90

Yep - it's a "backflush valve." I'm sure you see the hose Bibb fitting - after running a flush chemical, I can hook up a garden hose and close the valve, this forces the water to run through the system backwards (which loosens up scale deposits.)

Remove the hose, drain, open the valve back up, and refill the system. Off and running!

5-90

As long as you use a two-way cap and a remote overflow tank. Expansion is going to happen, you have to allow for it.

Most radiator caps are two-way jobs anyhow, so that's not a problem. But, as the coolant heats up and expands, it's going to start to purge itself. The idea behind an overflow reservoir is so that the system can draw coolant back in (as the coolant in the system cools & contracts.)

As mentioned, the volume tank (as part of the pressure system) has to have some airspace overtop of the liquid coolant, to allow for expansion. It only actually purges coolant past the pressure cap if there's something wrong - or the system was overfilled.

Either way, expansion of the coolant must be allowed for, or you're going to have something fail (and you hope it's just a hose - since it's easiest to replace. Blowing out a radiator tank seam is no fun whatever - I've seen it happen a couple of times. Yech...

(Although, I did get a good girlfriend out of one such instance, for about a year and a half...)

Nasty

Do you have a another image with a good shot of the heater control valve. I bought an '87 at the end of last year and just noticed that some of the vac lines are not connected and that there is no heater control valve. Trying to figure out location to splice one in as well as the right hookup for a blue van line.