If you have a Spectra CU369 Radiator...

[saxart]

If you have this radiator (could have been purchased through Rockauto.com or many of the "chain" parts stores around) I could use your help.

This radiator has three fittings on the passenger side tank. Two of them are smaller fittings for a transmission cooler (you can see the little red plugs in my photo below) and one of them is a larger fitting that sticks out about 1" and has a plug in it. (Circled in RED) This larger fitting basically caps off an open hole into the radiator tank. Without this fitting, the radiator won't hold coolant.



Does anybody know what size that fitting is? I removed the fitting from my radiator and I think it got tossed out when a friend was helping clean the garage last week. I contacted Rockauto AND spectra, but neither have any info as to what size this fitting is. It's an odd fitting in that it isn't pipe-thread, rather it seals with an o-ring at the base of the hex.



If anyone just happens to have a junk version of this radiator, I NEED this fitting, or even the thread type and size would work so I can source another plug.

[RodnRudy]

Take the threaded plug to a hardware store that has a thread gage and see what the size is. Then buy an appropriate bolt and while you're there get the o ring you need also. By plug I mean that copper fitting that the plug screws into.

[toolboxchev]

Ace Hardware, True Value have a good selection of stuff. It will not be in the Automotive Section, of course.

Lowes, Home Depot, have stuff all over their stores in multiple places. It only has to hold about 20 lbs of pressure. You may even find a plug in the electrical area.

All the Big Box stores have solutions just laying there, and most of the time no one to get you in the right area of the store.

[demian5]

Good ol "universal" stuff.

[saxart]

Thanks guys. I ended up taking the radiator to the hardware store. (left it in the back seat of the car in the parking lot) and tried some fittings in it. Turns out it was 3/8" pipe thread which surprised me because of the o-ring on the original fitting.

Secondary question. I've decided I want to mount the electric fan switch in this bung of the radiator. One of the things I can't figure out, is how to ground a switch that is mounted in a plastic radiator that only has one connection on it. (most of them only have one electrical terminal) Obviously most of these are grounded via their body as it's screwed into the block. In my installation, it will not ground that way. Is there some sort of a ring terminal I can put under it before screwing it in?

Please don't turn this into a discussion about electric fan switch in the block vs in the radiator. I know what I want. Just need to figure out how to do it.

[B. W.]

If the hex part of the brass bushing is wide enough you could tap it & screw a ground wire into it. (Simple & relatively clean)

Or:

You could look for a smaller diameter switch then use a steel busing between the switch & radiator. On the steel bushing you could weld a tab then run a ground wire off of this to the core support. (Not very pretty)

[demian5]

why not a brass and copper radiator?

[clay68c10]

I wonder if the coolant/water mix would work as a ground. Water is a good conductor. I've never checked the resistance of coolant mix, but it's worth trying.

[mike16]

with a multimeter you can check the quality of your antifreeze. I was taught to do it in the army back in 1980 but its an art lost to me in the last 38 years

[saxart]

Originally Posted by clay68c10

I wonder if the coolant/water mix would work as a ground. Water is a good conductor. I've never checked the resistance of coolant mix, but it's worth trying.

Yeah, it would probably conduct electricity, but then you'd probably start issues with electrolysis eating the radiator up.

http://www.griffinrad.com/electrolysis.php?tid=46

I think I'm going to change this up a bit and put the switch in the thermostat housing/water neck. That seems to solve a lot of issues but still gives water temp AFTER the thermostat, which is what I'm after.

[volksworld]

it would look pretty bad but you could hose clamp a ground wire to it...maybe with a small piece of hose over it...ground wire inside, clamp outside