The ask an MOT tester thread

[SpeckledJim]

Andy665 said:

Took my car in for its MOT last Thursday.

Passed easily, as I expected it to do but had an advisory - Valve stem slightly damaged (both rear) (5.2.3)

Checked all 4 tyre valve stems and all are in absolutely and unmarked condition.

Slightly miffed as I don't like seeing anything as an advisory, especially as I can see absolutely zero evidence of the potential fault they are highlighting

If I go back and query what can realistically be done - I do not see why an advisory should be noted when its clearly incorrect

I think if you're that fastidious, you should take the car for a pre-MOT non-official MOT immediately before the real MOT. So the chap who's going to do the real test does the test without logging in, and then tells you if he would fail or advise anything.

So you pay twice, but keep your clean MOT history.

There may be some eye-rolling, and maybe some gentle laughter drifting across from the break room, but brush that off.

[Athlon]

yeager2004 said:

Hi OP - hopefully not been asked before, but could you advise if the MOT for taxis differs from that of the normal class 4 test? I believe taxis are tested more frequently, but wondered if the test was any stricter.

if so, has this always been the case? Seem to recall on the 90s taxis drivers having really old and ropy Escorts/Cavaliers/Astras etc. with intergalatic mileages . Amazed if they would have stood up to more thorough testing.

Thanks!

Much tougher test that covers far more than the MOT in the case of black cabs at least, not sure on private hire but I expect the same applies.

The taxi testers I know of are universally hated for how strict they are!

[Athlon]

steveo3002 said:

what do you check for on rubber brake flexi's ?

Corroded ferrules, it they have degraded to the point you can see the fabric layer through cracks, bulges or porous when pressure applied, rubbing, twisted, stretching and security about does it!

[Defconluke]

Occasionally the dashboard throws a 'sidelight not working' message.
Both sidelights are working although one is a bit more yellow than the other - perhaps starting to deteriorate or maybe there is just a poor connection in the circuit that is triggering the message on the dash.

With no warning symbol illuminating on the dash and the light still functioning this shouldn't be an issue should it?

[Athlon]

Defconluke said:

Occasionally the dashboard throws a 'sidelight not working' message.
Both sidelights are working although one is a bit more yellow than the other - perhaps starting to deteriorate or maybe there is just a poor connection in the circuit that is triggering the message on the dash.

With no warning symbol illuminating on the dash and the light still functioning this shouldn't be an issue should it?

If the bulbs are working, that's it for us! You might get an advise form a super keen tester though (I wouldn't)

[keeling54]

Athlon said:

Accelebrate said:

How strict are the new rules around cat removal on cars with multiple cats? A popular modification on one of my cars is to swap the standard manifold which contains some restrictive pipework and a cat with an aftermarket manifold sans-cat.

Apparently the car would still pass the emissions test due to the second cat located in the mid-pipe, but I guess it would fall foul of the directive that any OE cats shouldn't be removed? That said, it's mostly concealed by heat-shields and I can't help but wonder how many testers have an encyclopedic knowledge of OE cat locations.

The rule is if it had them from new they should be there. That said, if I can see a cat fitted and it sails through the gas test with no issues I won't look too hard..In my mind the important thing is that it is clean, I test many cars that are standard but only used around town and have to put some effort in to wake up the cat, an arsey tester would probably fail them even though they are ok.

Just to add to this, there have been lots of Catalyst thefts recently from Lexus Rx400h's, the rear cat is stolen, mine was nicked this morning, the front 2 are in accessible so they can't get nicked... now I know the MOT rules are that if it came out of the factory with a Cat it should be present when tested, however I did read that it only has to be present if the car needs an emissions test, if it's emissions test exempt like a Rx400h is, a straight through pipe can be fitted. I'm of the view that a Cat should be present.

What would all you testers do if a hybrid arrived with the rear cat replaced with a straight through pipe.

[Athlon]

keeling54 said:

Just to add to this, there have been lots of Catalyst thefts recently from Lexus Rx400h's, the rear cat is stolen, mine was nicked this morning, the front 2 are in accessible so they can't get nicked... now I know the MOT rules are that if it came out of the factory with a Cat it should be present when tested, however I did read that it only has to be present if the car needs an emissions test, if it's emissions test exempt like a Rx400h is, a straight through pipe can be fitted. I'm of the view that a Cat should be present.

What would all you testers do if a hybrid arrived with the rear cat replaced with a straight through pipe.

Simple answer is we have flow charts! Me? if I could see a cat, pre or otherwise and it passed the test then that's all good. The criteria is a cat, not where it is fitted..

[ging84]

Are most MOT testers doing tests all day, or are they typically also doing service and repair work?
Which do people prefer doing?

[Second Best]

Great thread. Three questions, if I may?

1. For cars with active exhausts, do you work around them as part of the vehicle? For example, my car has a noisy bypass exhaust that it uses when cold (completely standard vehicle). If you put a probe in the exhaust it'd return ridiculously low emissions figures.

2. On that note, I know diesels get a good rpm check for emissions. I'm guessing decent testers let the engine warm up before they do the rev check, or is it meant to be done from cold? Do testers have to engage high rpms in petrol cars? Do you guys stick to neutral because of how the cars don't engage vtec/active exhausts etc?

3. Some vehicles are tested 6-monthly rather than yearly, and similarly I think cars that have been written off (Cat C/D) require an MOT before they go back on the road, irrespective of age. Do you, as MOT testers, have any legal/mandated requirement to take into account the purpose of the vehicle given it's more stringent MOT requirements? Or is it just "oh, VW Golf GTD estate on a 6-monther, Barry get it on the ramp"?

[Athlon]

ging84 said:

Are most MOT testers doing tests all day, or are they typically also doing service and repair work?
Which do people prefer doing?

I think it must depend on the garage, I test until mid afternoon as a rule then rotate onto jobs, but on a busy day I will be testing all day with the odd re-test as well.

I am happy testing but it is nice to mix it up with some other work, I also road test and do diagnostics which is better from a keeping clean point of view for jumping in and out of cars.

[Athlon]

Second Best said:

Great thread. Three questions, if I may?

1. For cars with active exhausts, do you work around them as part of the vehicle? For example, my car has a noisy bypass exhaust that it uses when cold (completely standard vehicle). If you put a probe in the exhaust it'd return ridiculously low emissions figures.

2. On that note, I know diesels get a good rpm check for emissions. I'm guessing decent testers let the engine warm up before they do the rev check, or is it meant to be done from cold? Do testers have to engage high rpms in petrol cars? Do you guys stick to neutral because of how the cars don't engage vtec/active exhausts etc?

3. Some vehicles are tested 6-monthly rather than yearly, and similarly I think cars that have been written off (Cat C/D) require an MOT before they go back on the road, irrespective of age. Do you, as MOT testers, have any legal/mandated requirement to take into account the purpose of the vehicle given it's more stringent MOT requirements? Or is it just "oh, VW Golf GTD estate on a 6-monther, Barry get it on the ramp"?

1. We work around them, the car has to be well warmed up before gas testing anyway but we will always find the right hole....

2. Diesels must be warm, absolute minimum of 60 deg oil temp, hotter the better, it can be a challenge in winter! Petrol cars are typically run at 2500 r.p.m. +or - 500, always in neutral.

3. Only twice yearly cars I can think of are taxi/psv and that is not an MOT so we are not affected by that one. And no, as far as we are concerned a car is a car, they are all approached the same and tested the same.

[Harji]

It may have been asked, but do you check for DPF removal? And have you failed a car for DPF removal.

BTW, I'm not asking for a 'friend', none of my cars have a DPF as built by the manufacturer at the time.

I'm asking as I am seriously put off buying a second hand diesel and not knowing if the DPF is there or not, I do not want one without it if the car had it.

[joshlambert]

Why are there so many MOT tests recorded at late night times when most MOT test centres are closed?

[stevemcs]

Harji said:

It may have been asked, but do you check for DPF removal? And have you failed a car for DPF removal.

BTW, I'm not asking for a 'friend', none of my cars have a DPF as built by the manufacturer at the time.

I'm asking as I am seriously put off buying a second hand diesel and not knowing if the DPF is there or not, I do not want one without it if the car had it.

Yes we check, but on some cars its impossible to see so they slip through, the tell tail sign is emissions higher thab they should be, soot in the tailpipe or if you can see the DPF welding.

Yes we have failed some, both on emissions and signs of being tampered with .

[Sheepshanks]

Athlon said:

2. Diesels must be warm, absolute minimum of 60 deg oil temp, hotter the better, it can be a challenge in winter! Petrol cars are typically run at 2500 r.p.m. +or - 500, always in neutral.

My oldish (2005 model) diesel Merc has had its last two tests done by the same Merc indie.

First time it was tested at 3.0 as there's no plated value and it passed at 1.17.

This time it was tested at 1.5 with oil only just over 60C. It still passed but it was pretty marginal, which irks me somewhat.


Is he likely to have used 1.5 in error or is it normal to test it at a tighter limit and see what happens, then only get more precise if there's an issue?

[Little Pete]

Harji said:

It may have been asked, but do you check for DPF removal? And have you failed a car for DPF removal.

BTW, I'm not asking for a 'friend', none of my cars have a DPF as built by the manufacturer at the time.

I'm asking as I am seriously put off buying a second hand diesel and not knowing if the DPF is there or not, I do not want one without it if the car had it.

I do check but it was a while before I got into the habit. I failed a VW Crafter a few weeks ago because I couldn’t get it through the emissions test. Apparently the DPF had been cut and re welded and then mapped out. The back doors were covered in soot and the smoke on acceleration was horrendous.

[Harji]

stevemc, littlepete, thanks. I'm half thinking of changing my Audi A6 2.7 to something more efficient (great car otherwise) but as I only go second hand route, I'm too wary to trust many of the older diesels.

[Little Pete]

ging84 said:

Are most MOT testers doing tests all day, or are they typically also doing service and repair work?
Which do people prefer doing?

I test all day, sometimes from 6.30 if we are especially busy. Same as Athlon, I get to do some road testing and we always have the odd classic that I enjoy working on, but generally my day consists of testing and MOT related admin, and doing quotes. It does get a bit boring sometimes. I have two other testers but they are mainly in the workshop, doing a few tests per week. One doesn’t like testing at all.

Edited by Little Pete on Monday 21st October 14:31

[Little Pete]

Sheepshanks said:

My oldish (2005 model) diesel Merc has had its last two tests done by the same Merc indie.

First time it was tested at 3.0 as there's no plated value and it passed at 1.17.

This time it was tested at 1.5 with oil only just over 60C. It still passed but it was pretty marginal, which irks me somewhat.


Is he likely to have used 1.5 in error or is it normal to test it at a tighter limit and see what happens, then only get more precise if there's an issue?

It’s unlikely he used a lower limit in error. Most vehicles have a value somewhere, I think on a Mercedes it’s on the VIN plate.

[Little Pete]

Little Pete said:

Harji said:

It may have been asked, but do you check for DPF removal? And have you failed a car for DPF removal.

BTW, I'm not asking for a 'friend', none of my cars have a DPF as built by the manufacturer at the time.

I'm asking as I am seriously put off buying a second hand diesel and not knowing if the DPF is there or not, I do not want one without it if the car had it.

I do check but it was a while before I got into the habit. I failed a VW Crafter a few weeks ago because I couldn’t get it through the emissions test. Apparently the DPF had been cut and re welded and then mapped out. The back doors were covered in soot and the smoke on acceleration was horrendous.

Thinking about it I think DPF removal is less of an issue nowadays. There are so many companies offering a cleaning service with before and after weights and flow rates that removal, cutting it open, re welding and re mapping really isn’t necessary.