how much coolant

[ghost123uk]

And is it phosphorus free ?

Hmm - I can't tell if you're having a dig at me for my naive question about the difference between phosphorous-free and phosphate-free

No dig intended CJH And anyway, it wasn't a naive question It seems from what I have read here and elsewhere, phosphorus / phosphate free is a preferred requirement. I reckon that stuff is likely fine though, I am the type that just likes to know stuff like this

[CJH]

No dig intended CJH

Hehe - thank you, I was pretty sure that was the case. As wikipedia says, elemental phosphorous is highly reactive, so it is nearly always found as phosphate rocks. So I think the requirement is probably better stated as 'phosphate-free', which is how EuroCarParts describe their red coolant in their Amazon advert.

[randbk]

When filling the expansion tank, should this be done right up to the top of the neck of the filler or should I leave space for the expansion to happen??

[Oldiebut goodie]

Look on the right - two marks with min and max alongside.

[randbk]

Thanks, but I was referring to the expansion tank on the left of the engine compartment with the black pressure cap. I think what you have shown is the top-up filler tank.

[ghost123uk]

Strictly speaking the one on the left is not an expansion tank, it is known as a "header tank" and it should always be full to the very brim. That other tank as per the pic should be about 1/2 full, ie somewhere between the min and max marks mentioned above ^^^. Best to check levels on both tanks with a cold engine, the one behind the flap can appear fuller when the engine is hot due to the expansion of the coolant. It gets sucked back from there as the engine cools down.

[California Dreamin]

Full to the brim mate...no space. If the coolant pressure exceeds the spring tension of the pressure valve in the Darlek Cap (around 1bar) coolant is released past the valve into the 'topup' tank. 'On Cooling' the antifreeze contracts creating negative pressure (vacuum) which opens a second valve in the cap, drawing the coolant fluid back into the system.

Martin

[California Dreamin]

John...beat me to the punch...lol....mines a better explanation

Martin

[randbk]

Thanks very much everyone! I always treat the coolant issue with a lot of respect as I do not want the engine to blow on me due to a lack of knowledge of the technicalities of it all !!

In this case, I had done all that I thought I should after replacing the tank as the old (original) one had split along a seam. I have then had to use PTFE tape on the Darlek Cap to create a better seal as fluid would escape from where the cap is screwed onto the tank after a run. After a while, it has started leaking again and I just wanted to check if I had over-filled it, which it seems that I had not!

Oh, the joys of a T25!!!!!

[ghost123uk]

Where did you get both the tank and the cap from ?

There are some appallingly made tanks out there which is bad enough, but there are also some dalek caps that simply don't work correctly from new. I had one many years ago, when I was still green behind the ears re T25 parts suppliers. It did not vent correctly and built up pressures that twice caused hoses to burst. It was this that then lead to my l/h bank to overheat, to the extent it resulted in me having to source a replacement engine. That did not go well and it took me 2 months, in the winter, before I eventually got it all sorted out. I got very good at swapping engines in the wet and cold on my back, and very proficient in bleeding the coolant system. Cost me a lot of money and hassle, all because of a duff new dalek cap from JK (and a blockage in the "T" piece on the bleed ring). And from reading on here for many years, I know I am not the only one to be in this boat.

There is no "come back" as far as I can determine. Their responsibility ends with just exchanging the faulty cap
I think that if a NEW part is responsible for damage then the guarantee should go further than simply replacing the cap (or voltage regulator / oil filter / wheel bearing / etc).

So, when you say "I always treat the coolant issue with a lot of respect as I do not want the engine to blow on me due to a lack of knowledge of the technicalities of it all !!" you are being very sensible !

[ladybird]

is it possible to check if a dalek cap works or broken

[ghost123uk]

is it possible to check if a dalek cap works or broken

Well, at the risk of starting a big debate =

Some say you should be able to blow down the little pipe, only way and that it should make a "quack" sound. They say you should not be able to suck air through it.

However, the well reputed Simon Baxter (of Brickwerks) said somewhere that some designs will NOT do this behaviour. Something to do with them needing to be screwed down onto the tank before the one way valve operates correctly (due to the way it is constructed). Now, whilst I have not spent hours investigating / testing dozens of caps, I have had quite a bit of both practical experience re these (see above ^^^) and have read a lot about it, both here and elsewhere. imho, what I recall Simon writing is correct. Others may disagree of course.

In my view, as it is so important, and not very expensive, if there is ANY doubt, just buy a new one off brickwerks

[ghost123uk]

Dalek cap from brickwerks link

[ladybird]

thanks ghost

[ladybird]

brickwerks price is good but quadruple the price when post is included
genuine vw over here is a better price but i need the part number as the vw guy said the sensor in the dalek cap comes seperate