Technical New radiator, rubber tube cover missing

[typecastboy]

I’ve just put a new rad on my 64 plate and filled up with coolant this morning. Noticed coolant dripping. On the plastic reservoir just above the minimum fill line is a little tube built into the plastic that allows the coolant to pour out like a little tap. I remember in the past that there was a little rubber cap that went over this to stop the coolant coming out. This was a new rad that I’ve had for a while so it’s gone missing.

I’ve bodged it with a screw and some blue tack for now but does anyone know where these can be bought? It’s not an OEM rad!

 

[Ralf S.]

That sounds odd... the little tube with the cap on it, not that the cap has fallen off.

The reservoir is usually pressurised so any hole or vent (or cap) would allow coolant to escape. Are you sure the "hole" is not blind? Various radiator/reservoir blanks have channels and ducts moulded into them which can be then opened up when they're making a radiator for a particular model that needs them (e.g. 500 vs Panda, air-con vs no air-con etc.).. otherwise they remain blanked off.

Other times, the hole is opened or closed by a bleed screw nearby that acts as a tap. Handy if you want to drain the rad/reservoir but can't access the "cap"/hole.

I did have a spare (un-wanted) hole on my old Alfa 155 radiatore one time. It just pissed out coolant so obviously needed a pipe or hose on it but my car didn't have one). It wasn't threaded either (I was hoping a regular radiator bleed screw would fit in there), so I couldn't stick a spare bleed-screw into it. In the end I used a short self-tapping screw that was covered in silicone sealant before I screwed in it.

Ralf S.

 

[typecastboy]

No it’s open. As soon as I poured coolant in above the minimum mark it started pouring out.

I’ve had it on replacement rad before. Comes with a small rubber cover and a small jubilee clip. I’ve ordered something that might work on eBay. There’s no tap or plug, it’s very odd. It would have been in the box but it’s been out of the box for months just hanging around so I must have thrown the box with it in.

I’ll take a photo later on in the week.

 

[typecastboy]

This is the offending little open ended tube on the radiator. I’ve bought some rubber “shoes” to fit over and secured with a small jubilee clip.

 

[Ralf S.]

Yes.. same thing on my old 155 rad. I didn't have the rubber "shoe" thing (looks useful to have lying around the workshop) but the stub was small enough that a self-tapper was able to screw into it. I smothered the threads in silicone sealeant before I screwed it in, for good measure and it never leaked.

One time it was useful to have it there... I used it to let out some fluid when I wanted to move the (separate) header tank out of the way to change the cam-belt..


Ralf S.