what's needed? Car been idle 20 months

If it's not exposed to any moisture it won't show any condensation,so unless you've left it somewhere with an almost emty tank exposed to large heat cycles to suvk air in & out there'll be negligible condensation.

The message from Chris Bolus contains these words:

Where do you think the air comes from to replace the fuel that's drawn off by the pump? Fuel fillers should have one-way valves in their caps, or some other way is provided for admitting air. If not - the tanks collapse. Sometimes the valve has quite a high opening pressure - early Corsas gave the most amazing WHOOOSH as you released the cap, drawing in loads of possibly very moist air in the process.

OK, so it's vented, but that's not a free passage - it will only allow air in as the fuel level drops. It's still not going to draw in huge quantites of water while stood in a garage.

The message from Chris Bolus contains these words:

True. However, it is the main cause of considerable condensation in vehicles which are in frequent use.

I've just done a quick calculation, and it shows that for a half-full tank of 40 litres total volume, nearly 1 litre of air is drawn in with a temperature change from 20 deg C to 8 deg C. Of course, when daytime conditions returns, 1 litre of ullage is expelled from the tank.

If the humidity of the 20 deg C air is greater than about 50 percent, then dropping the temperature to 8 deg C will take it below the local dew point, and that means that excess water-vapour must condense out wherever it can, such as the sides of the tank.

It rains on average every fourth day, meaning that for every fourth one of those temperature cycles, the air drawn in is 100 percent humid, and *any* drop in temperature will cause condensation.

Moral: Make sure the tank is full, and put a big pile of rags over the vent. Shove a tightly-wound oily rag up the exhaust pipe and engine air-intake, for the same reasons - but leave some dangling so you can see it's there.

The message from Zaru Bezh Naya contains these words:

That presupposes zero pressure to operate the cap valve. Even at only half a PSI it'll be plenty to prevent any breathing.

Sadly, not. A temperature change from 8 deg C to 20 deg C will cause a pressure rise of just over 0.5 psi. It depends on the valve design whether the excess pressure over 0.5 psi, or the whole of the excess pressure, is vented, and ditto for cooling, except that outside air will be drawn in (complete with water-vapour).

Will be lucky - mine didn't survive six months laid up and wouldn't take a charge. 20 mths, especially if the car has alarm / radio taking a trickle is probably dead territory.

They do vary, I've had one sit for three years and be dead as a parrot, but charged up and was ok for a while. But yeah, I'd budget for a new battery about now as well.

Thanks for all the ideas and info folks . . . . ho, hum. Now where's my toolkit and credit card then?

The Omega that I just revived after 18 months had a battery that was initially totally dead. A simple charge has brought it back to normal functioning; it will hold its charge if the car is unused for a week or so and has not failed to start the car.

Don't forget the oil and filter change......

Just restored an RX-7 this summer that had been lying exposed in a driveway for nearly 4 years. The owner had recharged the battery and started it once

2 years ago. Couldn't get it to start until I put new petrol in and even then it took some turning over so don't leave a lot of petrol in it. All brakes were rusted up but not worn so could be stripped down and cleaned up. The tyres had all cracked where the weight was as the rubber was brittle. Cat working fine, passed MOT although silencer a little rusty. Aircon needed recharge. Still running fine months later on same battery, haven't even looked at the plugs (though will soon). Would recommend an oil and filter change as a matter of course.

Still trying to get rid of the slightly musty smell inside though, any ideas?

Z

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Zimmy" saying something like:

Spray all the carpets and upholstery with Febreze and leave the windows open as much as possible in this weather.

I take it its not raining where you are then? :-)

Z

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Zimmy" saying something like:

Heh. The rain might do it some good.