2.1 woes

[Ray]

2.1dj. wbx vw recon/ new -only done 12k in 6 years, now pressurising coolant. Going in for sniff test next week and as its only done 12k should it be less expensive to fix as everything should come apart easier. I'm hoping so. More syncro expense!

[KarlT]

Sorry to hear that Ray. Most of us have been there.
Very poor for only 6 years/12K miles. Do you know who reconditioned it?
You may be lucky but who knows how many of the headbolts were replaced or even checked properly.

[tencentlife]

If you're going on the presence of bubbles in the pressure tank, then a sniff test is definitely required, because it's more likely to be as simple and cheap as a bad pressure cap. A cap that releases at too low a pressure will present just like a combustion seal leak.

Pressure cap and thermostats are regular scheduled maintenance items along with changing the engine coolant. The best cap, as in the brand I see having fewest failures, is the "Blau" brand, which are, surprise!, blue, but there is another brand that is also blue, so look for "Blau" embossed on top. The black ones have had the highest instance of early release from what I have seen.

[Ray]

It was one of the last wbx ,s that VW supplied. The chap that installed it reckoned it was a new unit. I have been through 4 caps so far and they seem to get stuck open and when banged on the bottom side they close and work again. I have suspected the top rail not flowing properly as the temp gauge doesn't come up to the middle as it used to. If I just bleed the top rail where the feed from the t/stat joins its then OK at least until it cools then back to how it was. I intend to replace all the pipes attached incase of blockages but thought I would get it sniffed anyway.

[syncrosimon]

Ray, sorry to hear your difficulties.

When you say pressurising the coolant what exactly are the symptoms. Is it blowing coolant into the top up tank?

If it is doing it every time you run the syncro then the pressure gauge on the expansion vessel is a good place to start.

Hope it is something simple. What is the engine number? If it is a last VW one it will start with the year of manufacture, then the number.

[syncrosimon]

I think the top rail bleeding is useful when first starting from a coolant change, but full flow cooling on a driven vehicle with an open thermostat will get rid of any air. I know CJ never used to bleed the radiator just relying on full flow cooling to rid the bubbles.

Also I had temperature fluctuations caused by a cheap repro thermostat and a new one from Baxter restored the rock steady needle and improved the front heater output.

The little bleed screw on top of the plastic thermostat housing uses a very small hole which is always blocked unless cleaned.

[Ray]

Thanks for the replies folks. Today when I was running it up to temp on tickover eventually the coolant started rising in the top up up tank with bubbles appearing in the top tank but the cap had gone open again so it was boiling. I have tried caps from all suppliers and they all failed. It seems strange that if pressure causes the cap to open, then when cool it should close again. It must be a small leak because the coolant does not overflow and returns to the top tank on cooling. I guess a sniff test will settle it.

[syncrosimon]

I wonder if the plastic lip of the expansion tank is miss formed, thus allowing coolant passed the seal. Might be worth sanding the top of the tank flat with a flat sanding block to make sure you have a good seal.

[toomanytoys]

What cap are you using?? a gen VW one or a cheaper GSF look alike.. the cheap ones dont work very well.. I used one coz it was on the shelf.. didnt last 6 months.. another tenner on a gen cap is still a lot cheaper than engine out..

[syncrosimon]

Today when I was running it up to temp on tickover

Mostly I find driving is the best way of getting air out. Best way of getting the thermostat open. I have driven 7 miles in the cold weather in the syncro and with the front heater on the engine temp was not sufficient to open the thermostat and the radiator was stone cold. So this time of year it takes ages to open the thermostat and you wont get the air out when the thermostat is closed. I would change the thermostat, then look at the sealing lip on the expansion tank where the seal of the cap sits. You can feel when the thermostat opens as both of the metal cross over coolant pipes that run to the thermostat will be hot. Before the thermostat opens only one will be hot.

[Ray]

I've used 2 genuine ones and 2 copies that are made by the same manufacturer. I sawed one of them open and they seemed intact just seem to get stuck in the open position, ? heat or combustion gases toasting the plastic.

[silverbullet]

Today when I was running it up to temp on tickover

Mostly I find driving is the best way of getting air out. Best way of getting the thermostat open. I have driven 7 miles in the cold weather in the syncro and with the front heater on the engine temp was not sufficient to open the thermostat and the radiator was stone cold. So this time of year it takes ages to open the thermostat and you wont get the air out when the thermostat is closed. I would change the thermostat, then look at the sealing lip on the expansion tank where the seal of the cap sits. You can feel when the thermostat opens as both of the metal cross over coolant pipes that run to the thermostat will be hot. Before the thermostat opens only one will be hot.

I'd second that. A good sustained rev up to 3000 will be required to push any air out and an airlock will displace coolant. Running at tickover doesn't get the pump working or coolant moving in volume, which is what's needed for an effective bleed-out.

Unless of course the coolant is being discoloured by combustion gases. Modern petrol is pretty sooty these days, must be all the ethanol?

[Simon Baxter]

Blau made the caps for Vw.
If you've been through 4 caps, then to me you have bigger issues.
Cracked head or liner seals.

[KarlT]

Struck me too, 4 caps seems like more than just bad luck!

[Ray]

In garage now - liner seals on No4 coolant in oil also. All came apart easily after only 12k miles apparently. Get it back next week. Thats the second wbx I have had do this, expensive hobby!