Check the Spec

MOT fail and advisory terms and how serious they are

Checking the MOT history of a car and looking at what it has failed on or advisories in the past are a good way to gauge the general condition of a car when looking to buy. There are plenty of different terms that the examiners will use to indicate fails or advisories and below are a list of some of the main ones to be aware of that can prove problematic to remedy.

First on the list is the dreaded tin worm and although modern cars are a lot better rust proofed than they used to be that doesn't mean that it isn't something that you should look out for. Indeed rust can be lurking hidden underneath a car in hard to spot places that can lead to very expensive repairs, so have a good look through the MOT history and see if anything has been noted in the past. Comments like “ Subframe mounting prescribed area is corroded but not considered excessive” are things to take note of as there is a strong likely hood that a spot of wire brush and hammerite has been used to remedy the issue, though it won't have as the corrosion may well be coming from the inside outwards and will soon rear its ugly head again, probably in the form of a MOT fail. Rust advisories and obviously fails all really need evidence of remedial work having been done properly to be on the safe side.

So if you see the words “ mounting prescribed area is corroded” approach with caution...

Suspension components:
Worn bushes, shocks and ball joints are the most common causes of fails when dealing with a cars suspension. Ball joints and shocks are an easy fix so should not be a cause of too much concern. Bushes are a bit trickier as it all depends on how accessible the bush in question is, if its easy to get at then they are cheap and easy to replace, but in some cases they can require the removal of say the entire front subframe, as was the case with my Alfa 156 which was a £5 part but took £500 worth of man hours to replace. You get the idea. The best thing to do is copy and paste the examiners notes into google and do a bit of research. If you do see any comments in the MOT history that mention suspension components as advisories then it is always a good idea to check whether the owner has had any work done to remedy the issues. MOT examiners don't always pick up to everything on a car when testing it so a more recent advisory free MOT test doesn't always mean the problem has been sort. Check with the owner.

Engine management warning light:
There are a million and one sensors on modern cars designed to make them run as efficiently as possible and get their laboratory measured emissions down to EU levels, though in reality most of them do very little for the running of your car other than to cause the dreaded EML to come on when they decide to go on the blink. So often when the EML comes on it is something that can be ignored, but then again sometimes it might be something serious, the only way to find out is to have the car plugged into a diagnostic computer to have the faults read. There are cheap OBD11 readers that can read generic codes but all cars will have plenty of codes that are specific to them and will need a garage visit to sort out.

Generally speaking though, a glowing EML is usually something that can be sorted out realitively easily and cheaply. Usually.

SRS (airbag) light:
This is an automatic MOT fail and although there are many stories on the forums of how it was just a loose connection under the passenger seat, the fact is that more often than not it will be a fault with the airbag itself, or worse still the SRS ECU, either way its a lot of hassle and expense, avoid!

List of MOT tester advisory phrases

Nearside Rear Suspension arm rubber bush deteriorated but not resulting in excessive movement:
Can be either relatively easy or very difficult to fix depending on the car, research on google.

Offside Front Ball joint has slight play:
Ball joints are an easy fix.

Nearside Front Track rod end ball joint has slight play:
Again, an easy fix.

Offside Front Outer Front constant velocity joint gaiter deteriorated, but preventing the ingress of dirt:
Usually an easy fix.

Offside rear floor pan corroded:
Any mention of corrosion needs to be treated with caution as the costs can spiral as often one bit of corrosion means there is more hiding elsewhere.

Offside Rear Brake pipe slightly corroded:
Usually a bit of surface rust will earn a comment like this, a light rub will determine whether the pipes need replacing but if they do it can be a fairly big job.

Front brake disc worn, pitted or scored, but not seriously weakened:
On their way out so will need replacing, its an easy job though.

Nearside Rear Brake hose slightly chafed:
Brake hoses differ from brake pipes and are an easy fix.

Offside Rear Suspension arm has slight play in a pin/bush:
A relatively easy fix for a competent mechanic.

Nearside Front Shock absorber has a light misting of oil slight misting:
A relatively easy fix for a competent mechanic.

Offside Front rear parking (secondary) brake grabbing severely:
Usually just a case of adjusting the brake mechanism.

Offside Rear coil spring broken:
Replacing a coil is a fairly easy job.

SRS light or ESC light illuminated:
An automatic fail and potentially costly to fix.