Stored car dripping water on monthly start up

[benjj]

Hi chaps,

After a bit of advice on this...

My old Citroen is currently being stored in an air-chamber at my local classic car storage place. As part of the deal the car is started and brought up to temperature every 30 days.

This was done for the first time today and resulted in two drips (100% water, not fuel or other fluid) underneath the car, both further back than where any of the water pipes go. In fact there are no pipes what so ever above where the drips came from apart from the exhaust.

The exhaust is brand new, stainless steel and has had less than 1000 miles through it.

I've asked a number of people and they've all said it is likely to be condensation from the exhaust. As this is the first month the car has been stored there really isn't any chance it will have affected the levels (if it is something else) so I can't really tell.

Has anyone else with a stored classic experienced this? Sorry for the primary school question but this is my first (fully restored) classic, the first time I've kept one in an air-chamber and the first time I've used a car storage place. Makes it hard not to be able to nip in and have a look with my own two eyes...

Cheers,

Ben

ETA - the drip only started once the car was started up, it has been dry as a bone for the last 30 days underneath...

[Arthur Daley]

I'm not sure what citroen you have but could it be condensation from the air con?

[benjj]

Arthur Daley said:

I'm not sure what citroen you have but could it be condensation from the air con?

Afraid not, no a/c on it.

[hidetheelephants]

Condensation from the exhaust as you've been told; at start up the exhaust is cold and the water vapour produced in the combustion process partially condenses on it. Repeated idling warm ups will gradually fill the exhaust with water until it finds a way out. Unless the car is taken for a drive(ideally an italian tune up!), the exhaust will not get hot enough to vapourise and expel this water.

[benjj]

hidetheelephants said:

Condensation from the exhaust as you've been told; at start up the exhaust is cold and the water vapour produced in the combustion process partially condenses on it. Repeated idling warm ups will gradually fill the exhaust with water until it finds a way out. Unless the car is taken for a drive(ideally an italian tune up!), the exhaust will not get hot enough to vapourise and expel this water.

Terrific, thanks for that, much appreciated.

[na]

things may well always work out fine

but to my mind starting the engine and running up to temp may help the engine and cooling system and possibly just about get the charge back into the battery but the car really needs to be driven to keep wrinkles away (and know about) on brakes, steering, suspension, tyres, clutch, electric motors - just keeping things used and moving

just my ray of sunshine for the day

[NHK244V]

That's why cars used in towns all the time need back boxes more often, you need a long hard run to fully warm the system all the way to the back to boil off the water that condenses as the system cools.
As an example the wifes escort has had 3 new back boxes since it was new in 97, the rest is mint but it's a disabled car only done 50K and all round town, it's be on it's 4th soon as i just filled the current rear box to get it through the MOT

[hidetheelephants]

benjj said:

Terrific, thanks for that, much appreciated.

No probs; lovely looking motor BTW.

[benjj]

Thanks to all on here. I went over there today to have a check and indeed it was just condensation forming in the exhaust once running. It is also probably being exascerbated by the fact that the exhaust is so new and has not had a chance to soot up at all and absorb some of the O2.

As for general storing tips - I'll be giving it a damned good blast at least monthly, especially as shortly she'll be shod all round in tasty winter rubber...

Thanks again all, not often something new comes alon g to stump me but PH is always there to assist.

[benjj]

NHK244V said:

That's why cars used in towns all the time need back boxes more often, you need a long hard run to fully warm the system all the way to the back to boil off the water that condenses as the system cools.
As an example the wifes escort has had 3 new back boxes since it was new in 97, the rest is mint but it's a disabled car only done 50K and all round town, it's be on it's 4th soon as i just filled the current rear box to get it through the MOT

This just made me as I aint got no back box - just a straight through growler!

[restoman]

Have you tried starting it at a different time of the month? Or even weekly perhaps? . . .

[RedexR]

NHK244V said:

That's why cars used in towns all the time need back boxes more often, you need a long hard run to fully warm the system all the way to the back to boil off the water that condenses as the system cools.
As an example the wifes escort has had 3 new back boxes since it was new in 97, the rest is mint but it's a disabled car only done 50K and all round town, it's be on it's 4th soon as i just filled the current rear box to get it through the MOT

Exactly that , I have collected spare backboxes over the years as I know I will use them on a 3:1 ratio (at least), I spoke to an exhaust fitter about this once and apparently some modern cars have a manufactured hole in their backboxes for just this reason. I imagine the situation will get worse with hydrogen powered cars which have water as the No1 by product coming out of their exhausts

[tonys]

RedexR said:

NHK244V said:

That's why cars used in towns all the time need back boxes more often, you need a long hard run to fully warm the system all the way to the back to boil off the water that condenses as the system cools.
As an example the wifes escort has had 3 new back boxes since it was new in 97, the rest is mint but it's a disabled car only done 50K and all round town, it's be on it's 4th soon as i just filled the current rear box to get it through the MOT

Exactly that , I have collected spare backboxes over the years as I know I will use them on a 3:1 ratio (at least), I spoke to an exhaust fitter about this once and apparently some modern cars have a manufactured hole in their backboxes for just this reason. I imagine the situation will get worse with hydrogen powered cars which have water as the No1 by product coming out of their exhausts

Not so sure it's that new an idea to have a hole in the rear box. IIRC, a friend's Saab had the same thing in the late 80's, if not before.