my 4.2 sc is using a lot of water any ideas (but not all the time)

Lots of info on this. Use search for coolant leak.

Could be:

1. Coolant tank split.
2. Radiator leak (especially bottom left)
3. PCV hoses
4. Head gasket gone (check oil filler cap for white gunk)
5. Split coolant pipe into heater matrix

I'll let others have a go now .. Pete? ....

i have checked for any signs of water/coolant but can not see any anywhere on or under the engine

Thought the 4.2 was supposed to be better than the early one, best thing to do is a pressure test on the system, it will find the leak... You can't see it because it will be small and the water will be getting pushed out when the pressure in the system rises it will be a fine spray and will evaporate before leaving a tell tale puddle underneath...

Most garages can do it for you, they pressurise the system with the engine off and you can then find the leak easier...  Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

thank you for helping i will get it booked in tomorrow and i will not sound like a tit

You could ask them to do a sniff test as well, basically they stick the probe they use to measure your emissions on the MOT in the header tank of the cooling system to see if there are any hydrocarbons present.

Hydrocarbons are unburnt fuel and would indicate if a cylinder head gasket had failed between the water jacket and a cylinder bore, the head gasket can fail between the water jacket and the outside of the engine as well which will usually leave a stain from the gasket area, or it can leak into the oil ways and turn the oil milky as said above... Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

thats a lot to write on the back of my hand pete,lol .thanks

Sc has has been to the doctors where it had the compression test and the sniff test all good but he did another test which i can not remember but it was something about changing colour and has been diagnosed with the head gasket needing to be replaced AAHHHHHH dose this seam right

Haylands wrote:

You could ask them to do a sniff test as well, basically they stick the probe they use to measure your emissions on the MOT in the header tank of the cooling system to see if there are any hydrocarbons present.

Hydrocarbons are unburnt fuel and would indicate if a cylinder head gasket had failed between the water jacket and a cylinder bore, the head gasket can fail between the water jacket and the outside of the engine as well which will usually leave a Sc has has been to the doctors where it had the compression test and the sniff test all good but he did another test which i can not remember but it was something about changing colour and has been diagnosed with the head gasket needing to be replaced AAHHHHHH dose this seam rightstain from the gasket area, or it can leak into the oil ways and turn the oil milky as said above...

Sounds about right, I used this once on a motor with a weeping head gasket, still going strong 20,000 miles later and didn't use a drop more water... does seem to do what it says on the tin... If it doesn't work, get the gasket done, cheap enough to "have a go"

http://www.kseal.com/uk/?gclid=CPLkpee5ztACFZQW0wodBfII6A Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

k seal dreadfull stuff

And why is that pray tell...??? Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

its not fixing the problem can also block other water ways had a jag several years ago that the dealer put it in 18 months in court to fight to get money back its not a cure its cowboy juice

how about steel seal been reading up on it and it sounds good

good luck in getting a garage to repair when it breaks down in the end garages hate cleaning out block full of the crap