td5 MOT emissions failure...

failed MOT today on emissions/opacity. The pass rate being 3.0 it scored 3.22. Injectors cleaned and took it for a blast, not much came out the back, it runs smooth but have noticed that the temp gague hardly even gets up to 1/4 of the way up. All filters changed recently and oil.
Anyone got any thoughts on where to start?

Fuel pump tweak

put some petrol in before re test

I`f get the temp gauge looked at as well - if your car is running that under temp when it should be at normal operating temp there is an underlying issue, might be simple, might not, but best to find out

If there is an air lock in the coolant would that be a possible cause? Or maybe the thermostat?
How wuold I tweak the fuel pump? Do you think that it may be overfueling?

robd75 said:

If there is an air lock in the coolant would that be a possible cause? No Or maybe the thermostat? No
How wuold I tweak the fuel pump? Search Do you think that it may be overfueling? Yes

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Loads of threads on fuel pump, it may have been played with to get a bit extra power.

it's not been messed with for power, it passed MOT last year when I had it with no problems or advisories. I did have a coolant leak and wonder whether now I haven't bled all the air out? Could this be a cause?

storm99 said:

Loads of threads on fuel pump, it may have been played with to get a bit extra power.

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It's a TD5 - not a TDi !!!!

Good spot...erm, he's gonna get wet hands then.

robd75 said:

it's not been messed with for power, it passed MOT last year when I had it with no problems or advisories. I did have a coolant leak and wonder whether now I haven't bled all the air out? Could this be a cause?

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My guess is that your engine is not reaching optimum temp and that is affecting the burn.

First thing I would change is the thermostat and as an experiment I would take off the viscous fan.

Do I need any special tools for the fan removal as Rave shows that I do? And Do I have to take the fan or rad out to get to the thermostat?

robd75 said:

Do I need any special tools for the fan removal as Rave shows that I do? And Do I have to take the fan or rad out to get to the thermostat?

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You definitely need to remove the fan, to access the thermostat and it's related pipes.

These are only one-piece items, I bought a 2-piece one which holds the pulley still whist the other actually undoes the fan.

TD5 fan spanner | eBay

You do not need to remove the rad, although it might make sense to flush it through with a hosepipe whilst the pipes are disconnected.

Bits you will need to buy:

1. OAT pink coolant - get 10ltrs just in case. You will probably use about 5ltrs;

2. A selection of good quality Jubilee clips to replace the original spring type ones.

3. The thermostat itself.

NB It is vitally important that you refill & bleed the cooling system fully before the job is finished. Failure to do can result in air-locks which are not good for the engine. See Rave for the procedure.

Have you checked yet to see if your viscous fan is locked? If it has this can also cause too much cooling and increased fuel consumption.

After the engine has warmed through, turn it off and check the fan - it should turn relatively easily. If it doesn't it's locked on, so not working correctly. Needs replacing.

Good luck

Dave