Bleeding the Cooling system?

[AngeloEvs]

Just a few questions about bleeding the cooling system ('87 1.9DG) that are not covered in the WIKI.

1. The plastic bleed screw located on the thermostat housing.

When opened, should water and air escape through this or just air? Mine appears not to have been fully tightened and I have been losing approx. a cupful of water every 700 miles or so.

2. Should the bleed screw be turned fully anti clockwise or just a few turns when bleeding the system and should it be fully tightened using finger pressure until no further movement is possible.

3. The cooling tank where you top up with coolant. On the top is a lug with a gap that seems to allow water and air pressure to escape. When I jacked the front up, it filled up and coolant started to escape from the top of the tank, is that normal?

4. The radiator bleed nut. Haynes manual says that the nut should be loosend three turns and not removed until coolant starts to escape. Is that correct or should it be removed completely?

5. The washer behind the nut. Undid the nut, gravity and sods law, washer dissappeared into another dimension. Have used a copper washer normally used on brake pipes until I get a replacement but what was the original made of?

First time I have attempted this on a VW and I seemed to have lost more than I replaced, a naughty word comes to mind $%^&*&*((*

[mirams]

1&2. I've never seen water come out of this screw, but I think you fully open it whilst bleeding and topping up. Then finger tight should be fine.

3. That's not normal, the pressure cap on the expansion tank should seal off the top-up tank so it can't overflow on a slope. You might need a new pressure cap - available from VW for about the same price as anywhere else. Additionally air must be getting in somewhere else to allow it to flow out of here.

4. Just loosen the screw and run the engine until water starts coming out then tighten it up again.

5. Anything should be fine for this I think, best not something which will rust up.

[AngeloEvs]

Thanks Mirams, just been out to the van and noticed water dripping from the top up tank. Water is getting past the expansion tank when parked nose up and filling the top up resevoir. Will check if GSF have them in stock.

[AngeloEvs]

Have I got this right for a partial loss of coolant (not a complete refill).

1. Pressure cap off and run engine up to temp squeezing pipes to assist water flow.

2. Slacken off bleed screw on rad (not remove) and open bleed screw on thermostat.

3 Rev engine at 2000rpm until coolant escapes from rad bleed screw.

4. Tighen Pressure cap and rad bleed screw but leave thermostat bleed screw open.

5 Have a breaK!

6 Repeat 1 to 5 above and then retighten all bleed screws and refit cap.

[Mocki]

the bleed screw in the engine bay is mentioned(at least in the write up i did), close it BEFORE the one in the rad, as the air is pumped past it first.

dont drop the revs untill you have done the rad bleed screw up........

[AngeloEvs]

Cheers Mocki, will do it again in the morning after I get a new pressure cap from GSF. It looks as though I have been driving with an unpressurised water system as the cap that is on it allows the coolant to fill the top up tank if parked on a gradient. Just hope no damage has been caused but I see a small amount of water coming out of the exhaust when I am revving the engine. Have had to put about a cupfull of water every 700 miles or so which is why I investigated the cooling system. Seems to run OK but once it is pressurised I fear that it will reveal a headgasket problem.

[Mocki]

condensation is normal in the exhaust, specially on LPG