Scirocco Register

'88 Scala 1.8 injection. Doing the final bits and pieces over the winter before using in the summer.

Its losing coolant, only been doing small journeys but over time I keep topping it up to above the low line about quarter a litre at a time. Been under it for ages and cannot see any leaks. Had it in the garage for a cam belt and they could not find a water leak anywhere either. It is not overheating, its running a bit bumpy but its always had and ive started another thread about that. No oil in water, dipstick is clean as is exhaust.

There is a bit of wet present on the top of the header tank see picture (red line is where it collects). Is this from the cap - would it be enough over time to experience the coolant loss I have?

This is not actually my car, mine has I think the original header tank and blue cap.

Thanks in advance.

You can lose coolant through the head gasket directly into the combustion chamber so no oil/water mixing.
Also, the heater matrix/connections can drip behind the centre console onto the carpet.
And to answer your question, yes you can lose it through the cap/level sensor too

mr.brown wrote: Mon Jan 28, 2019 4:58 pm You can lose coolant through the head gasket directly into the combustion chamber so no oil/water mixing.

Would there be any other symptoms of this? The only other issues I have are when the car cold starts, the idle is average but gets better as things warm up. If I then let it cool down a bit and go shopping the idle is really bumping on restart. Would a gasket blown this way show up on a block test?

mr.brown wrote: Mon Jan 28, 2019 4:58 pmAlso, the heater matrix/connections can drip behind the centre console onto the carpet.

nothing on carpets and no coolant smell when heaters on.

mr.brown wrote: Mon Jan 28, 2019 4:58 pmAnd to answer your question, yes you can lose it through the cap/level sensor too

Going to replace the header tank and go from there. Thanks

I would just replace the cap 1st, they don’t last forever and I’m finding I need a new blue cap every 3 to 4 years. They have a pressure relief valve in them which can fail.

mark1gls wrote: Mon Jan 28, 2019 6:36 pm I would just replace the cap 1st, they don’t last forever and I’m finding I need a new blue cap every 3 to 4 years. They have a pressure relief valve in them which can fail.

Thanks already on order, it would explain the build up of wetness around that area!

Its probably the tank not the cap. It can split and crack exactly where that line is. I've had two go exactly there, will only leak under pressure

unknownmale wrote: Mon Jan 28, 2019 8:47 pm Its probably the tank not the cap. It can split and crack exactly where that line is. I've had two go exactly there, will only leak under pressure

Ah interesting, where about in London are you?

frlrubett wrote: Mon Jan 28, 2019 6:26 pm Would there be any other symptoms of this?

A coolant smell from the exhaust.

frlrubett wrote: Mon Jan 28, 2019 6:26 pm
nothing on carpets and no coolant smell when heaters on.

Same on mine but that was just because the liquid had gone through the carpet and pooled in the passenger's footwell soaking the underlay. This only became apparent once I'd removed the carpet. It was also turned out the coolant was a weak mix so didn't really smell of coolant that much.

frlrubett wrote: Mon Jan 28, 2019 9:55 pm

unknownmale wrote: Mon Jan 28, 2019 8:47 pm Its probably the tank not the cap. It can split and crack exactly where that line is. I've had two go exactly there, will only leak under pressure

Ah interesting, where about in London are you?

SE19

So... it continues. Still a slow loss of coolant a top up every 100 miles or to keep the level above the minimum but have not been driving much recently due to the cold/wet.

Purchased new blue cap, stuck it on. Old cap looked knackered inside.

My mate popped over with a block test kit just to double check there wasn't any head issues. (he said it was a cheap ebay job one). Cold start head test, there was bubbles going into the test fluid but no colour change. Had a run around in it, re tested and there was still bubbles in the test fluid but no colour change. Bubbles got worse on revving engine. Tested for 5 minutes each time and it was a good seal into the test kit. No 100% confident in the test kits ability to pick up exhaust gasses but seeing bubbles in the fluid was not what I wanted to see.

No mayo, no smoke in exhaust, runs pretty well except its a bit bumpy on idle. No obvious water leaks, new water pump on cam belt change. Header tank seems to be fine, nothing wet around or under it. Checked connecting hoses and they all seem to be ok.

Shall I book it in to have a pressure test?

Is your car carb or fuel injection?

Carb cars have water running around the inlet manifold and there's a small rubber O ring behind the head which are common problems for leaks, because it's hot back there and above the exhaust manifold you could be losing coolant and it's turning to steam?

Gasket and rubber seal looks like this.

https://www.ebay.co.uk/itm/VW-GOLF-MK1- ... :rk:1:pf:0

Injection, would a water leak also bring air into the system?

Sorry just spotted your first post on carb/injection

Not sure about air in the system question?

From looking / thinking logically there looks like there are three scenarios..

1. Exhaust gasses are coming through the HG and bubbling into the coolant and the block test fluid I have used cannot pick them up. (cheap ebay variety)

2. There is an air leak getting into the coolant system from somewhere and showing as bubbles but as its not exhaust gas the block test fluid is not picking it up. I do not know enough about this to understand how it would work.

3. Something else which I have missed completely, I have been using an old header cap which could have introduced some air into the system and its showing now?



Here is the video with the engine running on idle about 5 mins after I started it up. As you can see there is bubbling but the colour has not changed to yellow to indicate exhaust gas.

https://www.youtube.com/watch?v=mnT9LDD ... e=youtu.be

Here is after a quick run around the block so a bit warmer showing increased bubbles on revving but again no colour change.

https://www.youtube.com/watch?v=FhZ0uxS ... e=youtu.be

I would say start with the cheapest possibility and work through based on peoples advice. The o ring sounds a good shout.

My old 205 gti used to use water but run fine. I was convinced it had issues but my Dad strongly. disagreed as it ran ok.

On frosty/real cold days i always noticed more of a steam cloud out the rear (maybe twice the size but not obvious) on idle than other cars but that was the only thing to notice and i assumed it was the full stainless system causing more condensation.

One day it finally starting powering through water and i limped it home with 10l i was carrying incase.

Carry emergency water, make sure your low coolant warning is working and just plod through all the possible avenues bud. Good luck and i hope it isnt the head like mine was. Sometimes your lucky and its not the big issue :)

Mick