VW Golf NCT Failure..

IRLBrian

Hi all. I had my 2001 VW Golf Mk4 Petrol tested today and failed an a couple items. I just had the car serviced and a new middle box installed on the exhaust as there was a hole. Unfortunately I still failed emissions. Passed this time last year with flying colours.

Here are the results:

Engine/Oil Temp 22 degrees
Low Idle (750rpm) CO 0.32% (above 0.50% fail)
HC 130ppm (above 0ppm fail)

High Idle (750rpm) Lambda 1.27 (not between 0.97 and 1.03 fail)
CO 0.32% (above 0.30 fail)
HC 130ppm (above 200ppm fail)

It took me an hour to drive to the testing centre and I only waited about 10 minutes so I'm surprised the engine oil temp was only 22 degrees.

Also failed on offside front worn ball joints in the front suspension. Passed all other tests.

Any ideas what could cause the emissions failure. I don't want to spend too much money on the car as it's already 14 years old. It's running fine besides the two failed items.

Thanks!

damon5

Wondering how you faired out with your dilemma because I barely passed emissions by the skin of my teeth,when I read your post It was practically identical regarding emission results,age of car and middle exhaust box recently replaced.Since the replacement the exhaust seems to sound a bit blowy so have to get that checked out as oxygen intake through a broken weld would mess up the results,the lambda too.
My CO and HC readings had trebled from the previous NCT test and was thinking was the exhaust a factor but decided to look into the problem more by looking at previous NCT result results,i noticed with the previous test that the engine oil temperature was displayed as 100c and emissions were fine but this last test the engine oil temp was 22c like youself :eek:
The car a few weeks back done a 350 mile trip with dipatene thrown in and also was well driven so engine temp oil etc was well up when arriving at the NCT,the thing when I checked was that the car had sat going cold for half an hour before being tested as they had a half hour backlog so the reason why the engine oil temp dropped to 22c.
On their website they state that emissions test has to be done when the engine oil temp is at a normal running temp so I,m really assuming that the test that was done on my car with a 22c engine - oil temp was the reason for high emissions and the car just getting through ...

damon5

Wondering has anyone else seen a correlation between engine/oil temperatures and NCT emission test results..

rex-x

Your engine oil wasn't 22 degrees, the tester just didn't put the sensor down the dipstick tube, it was floating in the air at the time of the test.

damon5

rex-x wrote: »

Your engine oil wasn't 22 degrees, the tester just didn't put the sensor down the dipstick tube, it was floating in the air at the time of the test.

Sorry anything to do with cars is not my forte,i just looked back on the NCR report and maybe I should have said engine/oil temperature wether that makes a difference because I omitted the / so as a layman could you please enlighten me further on your reply,many thanks ...

rex-x

They have a sensor the put down the dipstick tube to measure the engine oil temp but in recent years they simply don't bother using it so it stays on its stand in the 22 or so degree testing lane. Basically it never went anywhere near your car and has no correlation to your cars temperature.

damon5

rex-x wrote: »

They have a sensor the put down the dipstick tube to measure the engine oil temp but in recent years they simply don't bother using it so it stays on its stand in the 22 or so degree testing lane. Basically it never went anywhere near your car and has no correlation to your cars temperature.

Such a feckin scandle along with the rest that goes on in NCT centres around the country,my car just passed the nct but if it would have failed wouldn't I have had a case against them because they did the test with the temp being 22c when it states that it should be done at normal operating engine-oil.many thanks for your imput rex_x

damon5

rex-x wrote: »

They have a sensor the put down the dipstick tube to measure the engine oil temp but in recent years they simply don't bother using it so it stays on its stand in the 22 or so degree testing lane. Basically it never went anywhere near your car and has no correlation to your cars temperature.

But how a year ago when the engine-oil temp was 100c that it sailed though with that higher temperature ,was it that they probed down the dip stick tube then and didn't this time,how can they get away with this ..

9935452

rex-x wrote: »

Your engine oil wasn't 22 degrees, the tester just didn't put the sensor down the dipstick tube, it was floating in the air at the time of the test.

There is a good chance that the probe wouldnt fit down the golfs dipstick.
I have the tool which sucks the oil out the dipstick when doing an oil change but neithre of the tubes that came with it would fit down the dipstick of my 02 petrol golf

damon5

Thanks for replies though my cars a 99 astra,i meant that emissions,middle exhaust recently replaced and age were similar.The previous nct report was
LOW IDLE
engine/oil temperature 100c .. now test on 19.12.2015 engine/oil temp at 22c.
CO. 0.03 vol % ... now CO 0.20 vol%
HC 60 ppm ..........now HC 138 ppm

HIGH IDLE
Lambda 1.01 .......now 1.02
CO 0.04 vol % ......now 0.28%
HC 67 ppm ...........now 153 ppm

This is the first time that exhaust emissions jumped so extreme and the reason for that in my view was to do with the test being done at the much lower temp of 22c,previous tests range from 70c up to 100c temp and no problem with emissons.
Don't forget they were running a half hour late so my car was sitting outside for that half hour with engine getting colder by the minute.Is that not why we bring our cars for the test with an engine that has had a right good warm up,some higher rev on lower gear etc to blow the crap out because in my view readings are better on a high temp than a lower one just like the OP with his Golf and test done at 22c too,thanks....

Special Circumstances

A car that has been run for anything more than 30minutes (at a guess) will not cool to 22c in an hour.
Even if you start a car after being parked overnight, you will see real temperature rise to 30..50c very quickly.

easygoing39

@damon5,I think youre getting confused a bit.The oil temp was'nt at 22c,even a stone cold engine parked overnight will have a higher oil temp than that within 60 seconds running.The oil temp probe was'nt in your sump,it was still sitting in its rack alongside the test lanes,hence the 22c temp.So youre car,parked for 30 minutes would have an oil temp back up around 90c within 60 seconds of the car being restarted.

So youre car had hot oil,it failed the test on emissions.Time to get that issue sorted.