Question re Vetus water filler cap

[Guest]

This is the coolant filler cap off my Vetus M415 heat exchanger.

Simple question if I may: Is this just a blanking cap or is it some kind of pressure relaese cap? Reason I ask is that it has 0.9 stamped at one side.

Many thanks. (sorry photos are dire)

 

 

 

[andyb116]

It's a blanking cap, the pressure relief valve is on the header tank cap. (Which is normally a Renault item)

[Guest]

It's a blanking cap, the pressure relief valve is on the header tank cap. (Which is normally a Renault item)

Thanks Andy, just needed to be certain

[Mac of Cygnet]

It's a blanking cap, the pressure relief valve is on the header tank cap. (Which is normally a Renault item)

 

What header tank cap? My Vetus engine only has one cap, looking like Catweasel's. Is this because it's raw water (heat exchanger) cooled? I'd not like to think there was a part of my engine which I didn't know existed (which is quite possible, even after 9 years!)

[Tony Brooks]

I am not so sure that it is not a 0.9 bar pressure cap. I know it looks like a blanking cap but they do not usually have a metal disc in the middle of the rubber seal. The seal usually is a full disc retained by a rubber "nipple" in a hole in the metal cap. That metal "disk" looks very similar to the pressure valve found in plastic screw on expansion bottle pressure caps.

 

It would not surprise me to find a small vent hole in the centre "dimple" in the top of the cap.

 

If it turns out to be a pressure cap I am not sure that there will be a seat in the neck for a conventional pressure cap.

[Guest]

 

What header tank cap? My Vetus engine only has one cap, looking like Catweasel's. Is this because it's raw water (heat exchanger) cooled? I'd not like to think there was a part of my engine which I didn't know existed (which is quite possible, even after 9 years!)

Mine has a skin tank so has a plastic expansion bottle. The pipe to the expansion tank comes out of the thermostat housing (or did but I had to move it.)

The cap does puzzle me a bit on the heat exchanger though I am inclined to think that it works as a blanking cap.

http://destinynarrowboat.weebly.com/vetus.html

I am not so sure that it is not a 0.9 bar pressure cap. I know it looks like a blanking cap but they do not usually have a metal disc in the middle of the rubber seal. The seal usually is a full disc retained by a rubber "nipple" in a hole in the metal cap. That metal "disk" looks very similar to the pressure valve found in plastic screw on expansion bottle pressure caps.

 

It would not surprise me to find a small vent hole in the centre "dimple" in the top of the cap.

 

If it turns out to be a pressure cap I am not sure that there will be a seat in the neck for a conventional pressure cap.

Thanks Tony. the original filler neck (now removed as it leaked copious amounts of coolant due to being glued in with loctite from new) had no seat for what I would call a conventional pressure cap. I will look closer for a vent hole.

Edited August 21, 2014 by Guest

[bizzard]

I'd say safety valve cap. It'd be pointless making it complicated like that if it was just a plain cap.

[nicknorman]

look on the other side of it. If there is a disc suspended on the end of a short rod, that wobbles a bit, it is a pressure relief cap. If the underside is just plain, it is just a blank. However that rivet-type thing in the middle suggests it is has a rod / disc and so is a pressure relief cap.