Giving my car a good run before the NCT

Brendan Burgess

Brendan Burgess

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I had my car serviced last week and I have the NCT tomorrow. I only drive about 5000 km a year, so the mechanic suggested taking my car for a good long spin beforehand as that improves the emissions.

I hadn't heard that before and on this website, I see

"Give the car a good run beforehand as well so the engine is up to operating temperature. Arrive in plenty of time for your test."

If I am in traffic on the way to the test centre, could it result in a poor reading? Should I take the car for a 20 km spin on the motorway?

Brendan
 
I was given similar advice with old car to make sure you get car to operating level if concerned about emissions. So a spin could help. I was fortunate that my local centre is against the traffic. The car passed ok so it doesn't hurt.

Good luck with the car. Don't forget to buckle up the rear seat belts. Have heard that's a bugbear of the staff.
 
I nearly always take it for a spin on the M50 before a test. The high temps. apparently burn-off the gloop in the pipes.:D Or, at least that's what my mechanic tells me.
 
Plus don't get to your appointment way too early or the engine will have cooled down again by the time it's seen.
 
I think you want to have the car driving i.e. not stuck in traffic for at least 20 minutes if you can...
 
I think you're overthinking this! Just drive to the NCT as normal and arrive on time. If it passes it passes, if not get it sorted. Loads of old wives tales about NCT inspectiors not liking this and that etc. The last time I was at NCT I filled up the windscreen wiper reservoir using a 7up bottle I filled in the NCT centre. This was in full view of the mechanic who was about to start testing the car......still passed.
 
Emissions are a special case... you really don't want an older car being tested with a cold engine. The same engine cold v hot will have a totally different emissions reading. The same engine could pass hot and fail cold, and sorting out emissions problems is not trivial.
 
It makes a difference, drive in a lower gear than normal keeping the revs up, a couple of miles will be fine once the engine gets time to heat up, the purpose is to blow out deposit build up primarily carbon that through normal careful low revving journeys can build in your exhaust and throw off your emissions at the centre.

I drive in 3rd at 3500 - 4000 rpm for about four miles before I get to the centre and once the car is up to operating temp.
 
Dear Brendan

If your car's emissions are excessive, surely the right thing is to rectify the emission levels rather than trying to circumvent the test? It's such an attitude which saddens me and makes me fearful that timely progress will ever be made in the fight against global warming!
 
Brendan Burgess said:
What does a "spin" mean? 10k or 50k?

Brendan
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HI Brendan, I do my test over near the airport and I live on the Northside, so I usually take it for about a 20 - 30 km run up to Blanch/town and around. No more than around 20 mins. The mechanic said that you need to get up to 100 or 120 (for about 15-20 min) to clear the gunk. There are loads of options off the M50: M1 or N3 (Derry road) where you can hit that speed and turn back easily. If the M50/M1 busy the N3 is nearly always pretty empty and you can drive at speed safely.
 
Dan Murray said:
Dear Brendan
If your car's emissions are excessive, surely the right thing is to rectify the emission levels rather than trying to circumvent the test? It's such an attitude which saddens me and makes me fearful that timely progress will ever be made in the fight against global warming!
Click to expand...

If they are not excessive when driving, there is no real problem to rectify? Once the engine has gotten up to its operating temperature the emissions could be ok.
If the car is failing at operating temperature then there is a real problem.
Fingers crossed in this particular instance there is not.

The car should be tested at road condition temperatures.
Remember the scandal with Volkswagen and its defeat devices? Because the 'smart' car knew it wasn't in a road condition. With old cars they are too 'honest'.
 
Dan Murray said:
Dear Brendan

If your car's emissions are excessive, surely the right thing is to rectify the emission levels rather than trying to circumvent the test? It's such an attitude which saddens me and makes me fearful that timely progress will ever be made in the fight against global warming!
Click to expand...

No where was it stated that his emissions were a problem. It's such jumping to conclusions and subsequent accusations saddens me!
 
Don't have to worry about taking mine for a spin. the test centre is an hours drive away. If it fails that another hours drive plus return trips
 
The real answer, as usual, is that it all depends. Petrol or diesel? Old engine or new? Do you use an additive with your fuel e.g. dipethene? Does you car have a cat fitted and must it have one?

General rule of thumb is to have the car tested when the engine is warm. Bring your second key and arrive with your engine warmed up. Check in and pay, hand in your keys and then sit in your car with the engine ticking over until the tester comes to take it. "I was charging the phone, no mains charger with me bud."

I anyone has specific questions about their car, maybe they can be addressed with specific answers.
 
Sue Ellen said:
Not being nosey or anything but did it pass? :p
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Last time I arrived about an hour early and they did it pretty much immediately. I was about 30 minutes early this time, and I had to wait the full 30 minutes. But my emissions were well below the minimum level.

Unfortunately, for some bizarre reason my rear fog light is white rather than red, so he failed me for that. But he told me very helpfully that I can get a special tape from a motor factor which will turn the light red.

Good job, because I rang Audi about it and they would have to order the part which is €120 and they would charge more for fitting it.

Brendan
 
mathepac said:
The real answer, as usual, is that it all depends. Petrol or diesel? Old engine or new? Do you use an additive with your fuel e.g. dipethene? Does you car have a cat fitted and must it have one?

General rule of thumb is to have the car tested when the engine is warm. Bring your second key and arrive with your engine warmed up. Check in and pay, hand in your keys and then sit in your car with the engine ticking over until the tester comes to take it. "I was charging the phone, no mains charger with me bud."

I anyone has specific questions about their car, maybe they can be addressed with specific answers.
Click to expand...

There's not many things that drive me more mad than people sitting in a parked car (or e.g. waiting in front of a closed railway crossing) with the engine running for no ... reason.
Apart from fuel waste it is a clear sign that the environmental impact of burning fossil fuels just doesn't seem to be registering as a problem.
Apparently petrol is still too cheap.
 
newirishman said:
Apart from fuel waste it is a clear sign that the environmental impact of burning fossil fuels just doesn't seem to be registering as a problem.
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Not sure if it is problem in the first instance. It certainly isn't an issue in terms of a motorist trying their best to get their car to pass an NCT test, which is what we're discussing here.
 
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