Yesterday, I replaced the dalec cap with the new one.
As I took the old cap off, there was no air release sound this time.
Both tanks had gone down an inch or so.
I bled the system, out of the radiator, using the method with a one way pump valve (https://www.youtube.com/watch?v=eug3jfkobPo
There was a lot of air in there!
One possible explanation for this could (hopefully?) be that back when we first had the van, we noticed, after one journey, that 'this pipe' (see pic below) was not attached to the dalek cap at all.
After that journey, a couple of months ago, I mentioned it to the local garage, and they put the metal clip on it.
Could that explain the amount of air in the system, or am I just trying to find alternative reasons when the head gasket is staring me in the face?
Anyway, back to yesterday.
After I'd bled the radiator and refilled the water tanks, I drove for 30 minutes, with the heating on.
All seemed fine.
Heat went up to about half way, but no further, and no light.
This morning, I took another look.
The tank behind the licence plate still seemed nice and high.
The engine bay tank was pretty high, but had definitely gone down a bit (see pic below)
Unfortunately, it was raining while I was doing all of this yesterday, and I forgot to properly check for a leak.
There definitely has been a leak under the van. The landowner on the last site we stayed at saw it dripping, and I've seen some residue on our drive. I haven't got to the bottom of this yet though (not quite sure how to go about it!)
Other information ...
TONYT25T25 wrote: ↑28 Sep 2020, 08:16
I thought I would add, check the oil filler cap for white/milky substances if so this could be another indication of head gasket failure.
Here's a pic Tony ...
It seems fine.
Is that a good sign?
937carrera wrote: ↑28 Sep 2020, 10:20
It's a diesel isn't it, can you post exactly what engine it is, even better put it in your signature and update your profile with rough location.
As I'm pretty clueless regarding what the last engine was replaced with, here are some photographs ...
Do they help to identify the engine?
Apparently it (or 'half of it'?) has been replaced. I don't really remember what the guy who sold it to us said about that.
OK, that's the update.
Are you all still convinced that it's the head gasket? Is there anything else I should do/check?
The van is going into the garage tomorrow, because of this coolant issue and the amount of black smoke that it's pumping out of the exhaust.
Is there anything that tell them other than, "Don't skim the head gasket"?
Thanks again everyone!