brown gunky 'rustiness' in the coolant top up bottle

[Nicola&Tony]

I thought you'd said that water was only gushing out when you took the cap off the header tank? Or have I read it wrong?

Tony

[dugdog]

you said that you've got the blue "dalek" cap on your header tank.
Tony

thanks tony... the cap in question is actually black... but i take your point... will investigate further...

thanks again, it's SO helpful to have you guys out there...

cheers

[Nicola&Tony]

thanks tony... the cap in question is actually black... but i take your point... will investigate further...

Might be an indication that it's not a genuine one then, can you see the VAG logo anywhere on it?

Tony

[Nicola&Tony]

...given that the system is under pressure, and assuming there is a leak somewhere... surely that would DECREASE the pressure and the water(/antifreeze mix) would NOT be gushing out when the cap is unscrewed?

Sounds logical to me . . . still sounds like a faulty dalek cap. Gotta go to work now.

Tony

[dugdog]

Leaving the rusty discolouration to one side for a minute . . . you said that you've got the blue "dalek" cap on your header tank. These contain a pressure valve that lets water flow into the top-up tank from the header tank and back again, when required.



Tony

thanks tony - the cap in question is actually black... if that means anything?... will check it out...

presumably I'll need to re-pressurise the whole system once i've replaced the cap?

cheers

(ps worried that this may post twice, as previous answer 'disappeared'...

dd

[ermie571]

dd,

STOP!!!!!!

don't make a mountain out of a molehill!!! We don't know if there is a problem yet!!!

First check......see if your engine has remained pressurised.
I went down to mine yesterday. Its cold. Been parked a week, last ran on sunday. so its cold.

without starting the engine...took off cap (the dalek) one and the water is at the brim. Little dribble out, but van aint level.. Replaced cap.

what does yours do after being parked up over night?

Em
x

[Ian Hulley]

OK ... let's simplify things ... Here's what should happen.

The header tank (in the engine bay) has either a metal cap OR a black (slightly older) or blue (more recent) plastic Dalek cap which has a pressure valve built into it. This tank should be full to the brim at all times. When the engine is running and the coolant expands the excess pressure pushes coolant down the small hose to the top-up tank (behind the number plate). As the system cools if all is well the excess coolant is pulled back into the header tank, leaving the level in the top up tank near the 'Max' line just below the screw on cap.

If you look at the top-up tank when the system is hot the level will be above the 'Max' line.

To test for possible overheating problems put the heater controls to cold, blower fan to Off and give it a 20 minute run, pull up and quickly open the engine bay .... this is under maximum pressure, look BUT DO NOT TOUCH ANYTHING , any leaks or faults will now be evident. If you switch it off have a cup of tea the level of the top-up tank will have gone back down again.

Sounds to me like the system could fine but may need dropping and replace the coolant .... this should be done every couple of years anyway. The rusty crud is a bad sign though ... probably a sign of neglect in the past and could be an indicator of headstud trouble yet to come.

All the best, Ian.

[dugdog]

what does yours do after being parked up over night?

will check at the weekend... but I'm thinking there may be an issue with the 'dalek' - as system doesn't appear to be running into the top-up as it should...

will also to the 'don't touch anything check' suggested by Ian...

thanks all - will let you know how it goes.

onto the next query.... (see my latest (T Q&A=) thread if up for more fun with the new guy)

thanks again all

dd

[dugdog]

ok, so I opened the bleed valve (once I'd got the correct grill off) on a cold engine, (of course...) nothing - no air, no bubbles... normal for a cold one right? all seemed well...

a guy that works with me used to have a T25, and he wanted a look - so, I was about to show him how the coolant squirts out when you take the lid off... and it didn't - good news! - filled to the brim and blueish (with a little brownish gunk around the lid)...

(btw the lid looks exactly like the dalek one pictured above (VW logo and everything), just black...)

so, got the lid off and it was pretty dirty underneath... lots of brown gunk... the guy I work with referred to it as 'radiator gunk?'... (hmmm)

gave the lid a really good clean - i think it was just gunked up with the brown stuff... i gave it a good blow through and the valves seemed to be working fine (i seem to recall reading somewhere that you shouldn't be able to do that... but i may be wrong?)

anyway - also used my lunchbreak to get the top-up tank out and give it a good clean out - don't think it had ever been cleaned...will be topping up with coolant and seeing how we get on after the trip home this evening...


Q - DO I TOP UP THE TOP UP TANK TO THE MAX LEVEL??

thanks again all

dd

[ermie571]

When the engine is running and the coolant expands the excess pressure pushes coolant down the small hose to the top-up tank (behind the number plate). As the system cools if all is well the excess coolant is pulled back into the header tank, leaving the level in the top up tank near the 'Max' line just below the screw on cap.

so - when cold the top up should be at max. So yes, top it up before you go home.

Em
x

[dugdog]

yep - spotted that after re-reading...



thanks - will report back

dd

[Nicola&Tony]

dd,

STOP!!!!!!

don't make a mountain out of a molehill!!! We don't know if there is a problem yet!!!

"Don't panic!"

Tony

[dugdog]

so...after cleaning out the dalek... i put the coolant in the top up tank and drove home... took about 15 minutes... so maybe not really warm enough to check as per Ian's instructions... but maybe near enough...

anyway - the thing is - I had a look in the top up tank when idling... and there was a steady stream of little bubbles popping up from the inlet for the tube (INTO the bottom of the top-up tank)...

now... I'm wondering if this is just a bit of air coming through as I've had the lid of the header tank..

I'll keep an eye on it... but sounds wrong to me....??

dd

[Ian Hulley]

I had a look in the top up tank when idling... and there was a steady stream of little bubbles popping up from the inlet for the tube (INTO the bottom of the top-up tank)...

I'd pass on this van ... that's normally a sign of a cracked or leaking head.

Ian.

[dugdog]

now I'm gutted...

I got it checked out by a local guy who is supposed to be fairly straight up - and a VW mechanic... he charged me £100 to give it the once over - he didn't mention that the top up tank was empty - and told me that the seals on the head looked good...?!

...I only picked up on this issue by looking at the haynes manual and going through the 'weekly checks'... as a bit of a favour to the person letting me do the prolonged 'test drive'...

she doesn't want a huge amount for it - only £1300 for what could be a pretty good van on all other counts... (hopefully)

how much to sort this out? maybe I should bite the bullet and do a deal with her?

any advice gratefully received.

dd