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Omega Help Area => Omega General Help => Topic started by: Nick W on 03 January 2013, 13:49:36

Title: MOT emissions fail
Post by: Nick W on 03 January 2013, 13:49:36
Just collected my estate from its MOT failure.
The two small bits of welding are not a worry. I was hoping to get away with them, and deal with them later. An hours work should see them done properly.

The emissions part is a concern though.
According to the test CO is 3.06% when a pass is 0.3%, and lambda is 0.95 when 0.97 to 1.03 is allowed.
Now the car does take about 8 miles to get anywhere normal operating temperature, and leaving it idling for 30 mins doesn't even do that.

So, am I deluding myself that fitting the new thermostat will cure this, or should I be looking a bit deeper?

Thanks,
Nick
Title: Re: MOT emissions fail
Post by: amba on 03 January 2013, 14:03:38
Not sure about the full effects on the emissions,but mine used to take an age to get to temperature anywhere between 15-20 miles of rapid driving would just see the gauge get to normal .

Replaced the thermostat last year along with oil cooler and what a difference it makes.From home to top junction of Robin Hood Lane..you will know where that is Nick !! car has reached temperature and delivering full heat so assume fueling and cats are then happy.Less than 2 miles.

If you were contemplating replacing the stat that would be my first suggestion followed by a few litres of Super Unleaded and a blast
Title: Re: MOT emissions fail
Post by: Marks DTM Calib on 03 January 2013, 14:13:19
If its not upto to temperature then it wont be closed loop (confirmed by the Lambda values) and hence the issues you are seeing.

Replacing the stat should sort it
Title: Re: MOT emissions fail
Post by: Nick W on 03 January 2013, 14:17:41
Good, that will teach me to have new parts on the bench rather than on the car. I bought the new stat over a month ago when I found the heater wasn't working properly.
Title: Re: MOT emissions fail
Post by: Nick W on 08 January 2013, 11:19:32
Replaced the stat, and did the necessary welding at the weekend. It now reaches operating temperature in about a mile, and seems to pickup a little better. Hopefully this will explain the recent dropoff in fuel economy too.
At the retest it gave figures of 0.06% CO and 1 for the Lambda reading. So that's a pass for the next year. Colin's comment was that "the thermostat is  a stupid design on those", which I heartily agree with. Still, £17 for a new thermostat is better than the £240 in parts it cost me last year.
Title: Re: MOT emissions fail
Post by: b4ndit on 08 January 2013, 13:06:38
Result another years happy motoring ;D :y
Title: Re: MOT emissions fail
Post by: Marks DTM Calib on 08 January 2013, 13:25:59
Replaced the stat, and did the necessary welding at the weekend. It now reaches operating temperature in about a mile, and seems to pickup a little better. Hopefully this will explain the recent dropoff in fuel economy too.
At the retest it gave figures of 0.06% CO and 1 for the Lambda reading. So that's a pass for the next year. Colin's comment was that "the thermostat is  a stupid design on those", which I heartily agree with. Still, £17 for a new thermostat is better than the £240 in parts it cost me last year.

Always willing to hear where it should be located and at what cost in order to sit in the central valley cooling gallery (which of course a mechanic wont be able to tell you  ;) ).

For me its idealy located from a design perspective, the thing that could have been improved is the need to remove the link pipe to change it  :y