MOT and emissions

Hi, yesterday my disco flew thru its MOT without a single advisory hurray!, when i checked my emmissions it read: fast idle test pass:- CO pass 0.00% limit 0.20%, HC pass 22ppm limit 200.

I checked this with an old MOT from 2003 and the results are exactly the same, thats gotta be good right?

A year or so ago I was talking to a bloke who eats sleeps and breathes Landrovers and he told me to keep an eye on the emissions after your MOT as its a good indicator as to whether or not your head gasket is going (the idea is that if the HydroCarbon count goes up a lot your burning oil)

I was just wondering is this true? and at what number ppm would you start to worry? And are my emmisions normal (high/low) compared to the rest of you on this forum?

Last two MoTs I haven't been given an emissions sheet.

A bit like mine, at my first MOT at 20,500 miles the HC was 22 ppm and the following years it's been 00 12 01 17 12 08 12 and last year 13 ppm so I don't think it means too much perhaps the temp of the engine, the testing RPM and maybe the oil i'm using who knows, and my CO has always been 0.00%

Hydrocarbon is the unburnt fuel in your exhaust sample, at 13 ppm it is fine. If the HC goes up high it could be caused by many things, a faulty spark plug lead on a petrol engine for example will give a hihg reading, or with a diesel a dirty/sticking injector.

As the engine wears and gets towards the end of it's service life the HC climbs because compressions are falling ect and the engine is less efficient.

Rest easy as all is well.

regards

Dave