Expansion bottle query

[what2do]

There's a certain member on here who is aware that I have bought a second van so that mine can go to the doctors for the bodywork to be done. I bought a 1.6 td of eBay, I wasn't fussed about the minor details when bidding as I just wanted something for a few months (or at least that's what my other half has been led to believe!).

Upon visiting 'forum member' one last week, I think he thought I was fibbing when I honestly said that I hadn't been down on my knees to look underneath. Being a good sort, he duly got on his back and very quickly pointed out that the spare wheel and carrier were missing - it's good to know these things I thought!

Anyways, now that you have a understanding about how dispassionate I am about this particular van ( although I will service and maintain it because.....well it's a VAN isn't it?). I was topping up the coolant on Sunday when I noticed a perfectly round hole of about 6 mm drilled into the cap on the expansion tank. Initially, I just thought I'd buy another one, however, I thought about it a minute longer and wondered why someone would drill this particular hole and what may occur if I replace it. I drew a blank but wondered if anyone else had any suggestions before I change the cap and blow the van up Hollywood style!

Thoughts please. Mitch.

[what2do]

Nobody appears to be shouting STOP, a new cap will cook the engine!! Have to assume that I'm safe to proceed......

[ermie571]

I'm going to say....What the blithering heck...the only reason would be to vent pressure, surely....maybe a roadside repair that never got fixed??

If you do change the cap....check regularly for pressure at the rad etc until you are sure that over-pressurising isn't an issue!

Em
x

[what2do]

Exactly, but what MAY be causing the pressure, issue? Was it fixed, was the Daley cap not functioning correctly? Who knows?

Suck it and see I guess!

[ermie571]

Its a diesel.....head gasket???

[what2do]

Diesel - yes. Gasket - no. No symptoms being displayed, but that doesn't mean to say there hasn't been a gasket issue in the past. .???

[ermie571]

no expert....but if it is gasket it would push gasses into cooling system? this is vented through the hole in the cap??? thus stopping the symptoms??

also....why doesnt it lose water through that hole when the system is up to working temp??? interesting ....

Em
xx

[itchyfeet]

also....why doesnt it lose water through that hole when the system is up to working temp??? interesting ....

Em
xx

Does the temp guage get up to normal mitch?

[what2do]

Yes, the temp gauge gets up to normal - rather quickly. And yes ermine, rusty coloured water does seep from the hole in the cap. That's what drew my attention to it, brown stains on white paintwork.

[itchyfeet]

Id say swap thd cap let it heat up to temp while you watch it, make sure thermostat opens ( pipes hot both sides) then give it a drive somewhere not too far

[ermie571]

Yes, the temp gauge gets up to normal - rather quickly. And yes ermine, rusty coloured water does seep from the hole in the cap. That's what drew my attention to it, brown stains on white paintwork.

rather quickly...bet it will be a damn site quicker without that opportunity to vent....

[what2do]

Can't say at the moment because it ought to be venting through the dalek, will have to try sucking through it or borrowing one of the other van. Intrigued all the same.

[ermie571]

Can't say at the moment because it ought to be venting through the dalek, will have to try sucking through it or borrowing one of the other van. Intrigued all the same.

look forward to an update!