44 replies to this topic

[paul_s]

I noticed an odd hot / burning smell this morning in the mini on the way to work. I stopped when I got there and when I checked, I noticed the expansion tank had coolant seeping out of the seams. It also looks like it's distorted a bit and bulges on one side.

 

I replaced the thermostat recently as it was leaking around the housing, thought it was worth replacing the stat while I was there. I did fill it up slow and checked for airlocks when I replaced the coolant, but could it be that? 

 

It's been running fine for a few weeks, so I thought it was all good. As that's the last bit I touched, and recently, I'm guessing I've ballsed something up though..?

[jamesmpi]

You need a new expansion tank cap and possibly a new tank. If you have a search you'll come across a few threads about how naff some caps are.

It sounds like the cap isn't releasing the pressure thus causing the tank to bulge

Edited by jamesmpi, 20 August 2013 - 04:32 PM.

[jamesmpi]

Have a read of this
http://www.theminifo...p/#entry2865065

[Ipod]

Cap, and new tank needed imo

[Carlos W]

I would think the cap should vent before blowing the tank up like a balloon but can't remember on later models

[Ipod]

but the valve in the caps fail, and dont vent, they rust up, get gunked up, iv had it and know a few on here who had the same problem..miniman redford at brands was a goodun, expansion tank looked like a balloon and the seam had gone lol, lucly it was the mini fest and there was stalls there

[miniman retford]

but the valve in the caps fail, and dont vent, they rust up, get gunked up, iv had it and know a few on here who had the same problem..miniman redford at brands was a goodun, expansion tank looked like a balloon and the seam had gone lol, lucly it was the mini fest and there was stalls there

And a nice RAC man to fit it so i didnt get me hands dirty

[tmarmsi]

same thing happened to me driving to MITP, 3 and half hour drive and bloody thing sounded like a boiling kettle with water spitting out of cap, cap has been replaced and all is fine for now would love to find a better alternative though

[paul_s]

Mine's not quite as bad as a balloon, but it's definitely bulged slightly on one side! I'll get a new tank as well as a cap I think, to play safe.

 

I'm assuming it's not worth the risk of a secondhand expansion either, and I should stop being a cheapskate and buy a new one..? 

[jamesmpi]

Second hand expansion? Tank or cap? Lol

You could buy a second hand tank or cap or both if you know that both are in a useable and working condition. Many people have bought new caps and the fail in months of purchase. There are many cheap and nasty copies out there. Best bet is to buy from a respected source

[paul_s]

Hah, that's what happens when you post just after lunch!! Secondhand tank I meant! Although Minispares have tanks for £60ish (minus TMF+ discount), so that seems reasonable!

[miniman retford]

Mine was split on the seam against the inner wing so could'nt see where it was leaking until it was taken off,

got mine on the day from minisport for £45.

[jamesmpi]

I think smithy bits do them for £40. I think they are genuine ones too

[Minimad100]

Had almost the same problem yesterday, although no bulging tank, popped into DSN classics (my local supplier) bought a new cap and its sorted!!!!

[paul_s]

Fitted a new tank and cap at the weekend, and driving back from work yesterday I got the same smell. Tank was bulged again, but went back to shape once I'd taken the cap off (carefully!)

 

I ran it up hot again, with the cap off, just in case there was any air in there. It looks like it boiled up and started spewing out the top. 

When it's running the hoses all feel hot (very hot), and the temperature gauge reads 'normal' (just below the halfway mark). Any thoughts as to what to check next?

 

I'll take the thermostat out and test that when I get back tonight, but if all the pipes (top and bottom, and the radiator) are getting warm seems to me it's working as it should?