Please help... white smoke!!!

[Is200owner2004]

Please help I recently bought an 04 is200 it had a stainless steel 6 branch manifold and then it was straight piped to the back box I had no issues only it was far too loud so decided to put a stock exhaust and cat but kept the 6 branch manifold since I have done this there is excessive white smoke coming from the exhaust until the car reaches temperature the car is not over heating also missing 2 o2 sensors could this be the problem? I know there can be a bit of smoke but this is excessive. Car drives and idols perfect no other issues. Any help or advice would be appreciated. 

[Duggie B]

Looks perfectly normal to me, is it smoke or just steam upon first start up with low ambient temperature then dissipates once exhaust is hot ?

[VFR]

Looks like steam to me & from experience stainless systems make more.

Hover you hand over the outlet and you will see the water droplets & your hand will become wet, oil will, well be oily.

[Is200owner2004]

I left it running idol for 30 mins and the temperature hand reached halfway never went above it but the smoke was still there. If I take it for a drive it disappears once she heats up. Could it be that I'm not driving the car enough? I keep her in my shed and start her up every so often but don't drive her much. 

[Duggie B]

13 minutes ago, Is200owner2004 said:

If I take it for a drive it disappears once she heats up.

I think that's your answer, the exhaust isn't getting hot enough at idle and moisture is collecting in the back box (boxes), but when the car is driven the exhaust heats up to such a temperature it 'dries' the water vapour before the exhaust gases exit out through the exhaust, I dare say if you were to rev the car whilst it is idling you would see water droplets emit from the exhaust (letting the car idle is possibly letting water collect in the back boxes making the situation appear worse)

[Is200owner2004]

3 minutes ago, Duggie B said:

I think that's your answer, the exhaust isn't getting hot enough at idle and moisture is collecting in the back box (boxes), but when the car is driven the exhaust heats up to such a temperature it 'dries' the water vapour before the exhaust gases exit out through the exhaust, I dare say if you were to rev the car whilst it is idling you would see water droplets emit from the exhaust (letting the car idle is possibly letting water collect in the back boxes making the situation appear worse)

This is the car after sitting idle for 30 minutes. Surely if it was a major problem eg head gasket I would know. Thanks for your help 

[Barry14UK]

Suggest you remove oil filler cap and check there is no evidence of water mixed with oil on underside.  Could you do a compression test on each cylinder? Sometimes a crack can close up as engine becomes hot.  Hope it's not that or head gasket.

[Is200owner2004]

8 minutes ago, Barry14UK said:

Suggest you remove oil filler cap and check there is no evidence of water mixed with oil on underside.  Could you do a compression test on each cylinder? Sometimes a crack can close up as engine becomes hot.  Hope it's not that.

Checked under the cap and there's no gunk at all. Wouldn't know anything about a compression test at. Hoping that's not my problem 

[Big Jim]

It's just condensation in the exhaust. just check out other cars first thing on a cold morning, 

[Barry14UK]

In a good engine a compression test should show a very similar good figure for each cylinder. testing each individual cylinder, one after the other.  This is done by removing a spark plug and either screwing what looks like a large tyre pressure gauge in place or the end of spark plug or the end of a connector of compression gauge.  The engine is then uniformly turned over either manually or electrically to obtain figurers.  I have done this a number of times.  If figure is lower in one cylinder it denotes one of several faults which will include defective head gasket, erosion of head material to water way or crack.  This is less likely these days, although I have experienced it in the past and needed a second hand head cylinder head.  But head gaskets do fail as one did on a Camry I once had which also caused water to overheat and overflow out of header tank.  Pressure test on cooling system by radiator might also be helpful if build up of water in exhaust system can be excluded.

[steve2006]

Water is just a product of fossil fuel combustion, if you look at your combi boiler flue on these cold days you see the same “smoke”

As mentioned water vapour tends to condense in the rear exhaust sections then turns back to vapour when they warm up enough.

Just take it out on a spirited drive run for 20 miles then recheck it.