Head gasket's ducked. Are you losing coolant, too?

Hi rebel2cv,
in Winter, some modern water-cooled engines can suffer from 'mayo' under their oil filler caps, even though their cooling systems are thermostatically controlled.
There's no such control on A series engines, so we have to do the thinking in that respect.

On a 2cv, the position of the oil filler/breather means that if the grille muff isn't in place during cold weather, the breather is chilled so much that water and oil can condense out of the vapour laden gas which is passing through it.
If the breather is warm enough, those byproducts of combustion don't condense out in the upper chamber, but pass through the breather and into the air filter to be burnt in the engine.
Or in your case, they'd have been discharged into the 'catch tank'...
( Note that most of the oil is supposed to be caught in the lower chamber of the breather, from where it drains back down into the sump.)

The amount of mayo in your photo was quite small compared to some I've found in the past, where it was impossible to top up the oil because the upper part of the breather was completely clogged.
In that situation, a clean up and oil change was advisable, but if there were only traces of gunk under the lid, a couple of long journeys with the muff in place would usually restore equilibrium.

ken.

an oldy but a goody

getting back to the reed-valve faux-breathers......it's sorted the mayo in my engine, but is that more luck than judgement? what's the opinion on these dump-valves??? don't want to be accused of being a boy-racer!!!

W

Ok thanks ken, filter is going on and I'm off to work 2-10 so it'll get a good burn tonight when nowts on the road!

Ok so, drove the car to work, first it refused to start, then every time I wanted to move it kept stalling, then about a mile down the road it started missing, and backfired twice then cut out. As I was doing about 40 I bump started it in 3rd drove on and it did it again. Got it to work and left it, I've put everything back to standard except the exhaust, and I'm seriously wondering if it's worth the hassle, someone please convince me it is!!!

of course its worth the hassle, its part of owning a classic

Yes I know, I was in a rather foul mood when I wrote that, apologies!

Go and test-drive a generic Korean diesel hatchback. THAT's why it's worth the hassle.

Haha that bad is it?!

No, you're right.

It's not worth it.

I'll give you two hundred quid for it and I'll pick it up at the weekend.