Unable to open coolant bottle!

[sarros]

Hi all,

I'm new to this forum and really hope you can help! I have a B180 2012 and my coolant top-up message has appeared. However, the cap won't come off (engine stone cold). I can turn it about 3-4 cms but no more, there appears to be a plastic lip that stops it from turning any more. Any ideas?

TIA

 

[Trickythemerc]

Just an idea, but do you need to press down on the cap before you turn it.

 

[sarros]

Sadly no, we can neither push it down or pull it up :/

 

[whitenemesis]

Have you tried lifting it as you turn it? There may be a slot to release it before the max turn has been achieved?

 

[James Copeland]

Have your read the manual?

 

[sarros]

Yes we read the manual but it bears no mention of any security or plastic lip - it just do a half turn and wait...we can't even turn it a quarter turn before it is physically blocked. It doesn't lift at all, there is no play in it. I wondered if Mercedes France fitted a special cap to prevent us from topping it up ourselves and therefore they charge us? The problem is, they are 20 minutes away by car so by which time, the engine will have heated up too much to top it up. This is so frustrating!

 

[putbinoot]

Just a thought but when the plastic hits is that just not when you should pull up on the lid. Maybe it's not what you think of as a threaded cap where you have to keep turning, maybe a half turn then lift.

 

[Jockcl500]

I have never any type of lock on a coolant cap, it has probably been overtightened to the point it has broken, I would turn it off with whatever force nessesary, get a large pair of waterpump type pliers which should turn it off and then buy a new cap.

 

[whitenemesis]

Just a thought but when the plastic hits is that just not when you should pull up on the lid. Maybe it's not what you think of as a threaded cap where you have to keep turning, maybe a half turn then lift.

Or maybe push down at this point to get past a possible "safety-lock"? That is, turning to the stop allows steam to escape under pressure without the cap flying off?

 

[optimusprime]

Well good job poster is not a brain sergeon. Get a wrench on it ,,it went on it must come off 9 posts on this .

 

[Deleted member 149005]

Are we talking about the cap on the expansion bottle or on the radiator?

 

[Flyinspanner]

3 Weetabix.

 

[Petrol Pete]

Probably on the expansion tank, unlikely to be a cap on the radiator. I would pop the overflow hose off and try to top it up from there. Photos please Sarros.

 

[grober]

These plastic caps are normally 2 part -the cap- and the pressure release valve-the later usually clips into the former on first assembly. The two have probably come appart as suggested. Forceable removal will possibly leave the valve section stuck in the reservoir but should be removable with the judicious use of two screwdrivers as levers taking care not to damage any sealing surfaces- you need a new cap on hand before attempting this.
an example from BMW!

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