What IS The Green Cap ?

[topgazza]

Hi everyone...

Slightly bizarre question to ask for my first one but....

Just checking the oil/water etc under the bonnet of my 2005 Passat Estate 103 TDi when I noticed, on the right hand side of the engine bay in front of the windscreen washer bottle there is a green screw cap. On removing it there was a small dip stick attached to teh cap and a black, oil type fluid inside.

Can't find any pictures or references to what this is in the VW hanbooks and I've read the thing from back to front. No sign or mention of it in any of the engine bay pictures either...what is it ?

[stuart]

Sounds like the power steering resovoir.

[devonutopia]

I'd say its the PAS as well. My pump/reservoir sits right by the washer bottle too.

[topgazza]

Thanks guys. That was my suspicion as well but it was odd that its not mentioned in the "Tips and Maintence " section. Its down to minimum but no mention of the type of fluid required to top up so can I assume a generic PAS fluid will do or does it use engine oil ?

[stuart]

Do not use ordinary PS oil or engine oil for this! you will cause a lot of damage if the incorrect oil is used

If it has a "GREEN" cap, I belive it is hydraulic mineral oil that is used, VAG part number G002000. If you speak to a VAG specilist or dealer they can advise you about this.

It may even show the number on the resovoir.

Stuart

[topgazza]

Thanks Stuart.

The res has a plastic "cover" around it but I'll check in the morning. VW obviously don't consider it to be a "DIY" top up...which is weird as they trust us with brake fluid....

[gresty]

ATF oil is just as good as mineral hydrulic oil.

[stuart]

Having worked at a dealer for 14 years I have seen the results of putting ATF in a car system designed for hydraulic oil.... for a start the hydraulic oil is just a little thicker than water....

Almost every car we had in the workshop had to have either the pump OR rack replaced if not both. It attacks the seals.

If you want to use ATF or any other oil, other than the correct grade/specification be prepared for the expence

[topgazza]

Appreciate the tip gresty but I would be mixing ...not a good idea I thnk.

I'll pop into my local VW dealer tomorrow