The Cat and the M.O.T.

[Barkas]

Ive booked the Blingo 1.9D in for an MOT test, it will be interesting to see what happens as I removed the CAT from the exhaust system 4 years ago, this year the new rules apply to CAT,s, if a CAT was fitted as orig equipment by manufacturer, then one must be fitted when presented for MOT test.
I will let you know what happens. Cheers

[geoff]

Lets hope your MOT Tester needs an eye test .......... good luck...

[labrador]

Ive booked the Blingo 1.9D in for an MOT test, it will be interesting to see what happens as I removed the CAT from the exhaust system 4 years ago, this year the new rules apply to CAT,s, if a CAT was fitted as orig equipment by manufacturer, then one must be fitted when presented for MOT test.
I will let you know what happens. Cheers

Don't worry a diesel only has a smoke test,not a full emission test.If they fail it on having no cat ask them to check their manual chapter 7.1 if they still refuse to pass it appeal to mot inspectorate.I believe their manual states that on doing an emission test they need to check that a cat is fitted they only do emission test on petrol.

[stuartinlancashire]

Labrador, I thought under the new rules the tester was supposed to check for the obvious removal of any emission control and safety devices that where fitted as original equipment by the manufacturer such as CAT, DPF, EGR valves, airbags, etc.....?

[Coco]

From the latest online MOT test manual:-

7.1 Exhaust System 7.1 - page 1
The M.O.T. Inspection Manual Issue Date April 2013
Information Method of Inspection Reason for Rejection
The overall security of the exhaust system
should be assessed; one or more exhaust
mountings missing may not be a Reason for
Rejection.
A durable repair to an exhaust system which
effectively prevents leaks is acceptable providing
the system is structurally sound.
A minor exhaust leak from, for example, a
connection joint or a pin hole, is not a Reason for
Rejection,
1. Check the security of the exhaust system.
2. With the engine running, check the exhaust
system for leaks.
3. On petrol engine vehicles that qualify for a full
catalyst emissions test, check the presence of
the catalytic converter.
Note: To ascertain whether a vehicle qualifies
for a full catalyst test, use the flow charts in
Section 7.3.C disregarding the result of the
Basic Emissions Test.
4. During all parts of the emissions test relevant
for the vehicle, assess subjectively the
effectiveness of the silencer in reducing exhaust
noise.
Note: For vehicles not subject to an emissions
test, the engine should be revved to around
2500rpm or approximately half maximum
engine speed if this is lower.
5. On Class 5 vehicles only, check that the
exhaust tailpipe is positioned so it is unlikely
that fumes will enter the driver’s or passenger
area.
1. An exhaust system not adequately supported.
2. A major leak of exhaust gases from any part of
the system.
3. A catalytic converter missing where one was
fitted as standard.
4. A silencer in such condition, or of such a type,
that the noise emitted from the vehicle is clearly
unreasonably above the level expected from a
similar vehicle with a standard silencer in
average condition.
5. An exhaust tailpipe positioned so that fumes
are likely to enter the driver’s or passenger
area.

Section 3 applies.

Once again, a Diesel is subject to a smoke test.

For the full version, look here:-

http://www.motinfo.gov.uk/htdocs/

[labrador]

From the latest online MOT test manual:-

7.1 Exhaust System 7.1 - page 1
The M.O.T. Inspection Manual Issue Date April 2013
Information Method of Inspection Reason for Rejection
The overall security of the exhaust system
should be assessed; one or more exhaust
mountings missing may not be a Reason for
Rejection.
A durable repair to an exhaust system which
effectively prevents leaks is acceptable providing
the system is structurally sound.
A minor exhaust leak from, for example, a
connection joint or a pin hole, is not a Reason for
Rejection,
1. Check the security of the exhaust system.
2. With the engine running, check the exhaust
system for leaks.
3. On petrol engine vehicles that qualify for a full
catalyst emissions test, check the presence of
the catalytic converter.
Note: To ascertain whether a vehicle qualifies
for a full catalyst test, use the flow charts in
Section 7.3.C disregarding the result of the
Basic Emissions Test.
4. During all parts of the emissions test relevant
for the vehicle, assess subjectively the
effectiveness of the silencer in reducing exhaust
noise.
Note: For vehicles not subject to an emissions
test, the engine should be revved to around
2500rpm or approximately half maximum
engine speed if this is lower.
5. On Class 5 vehicles only, check that the
exhaust tailpipe is positioned so it is unlikely
that fumes will enter the driver’s or passenger
area.
1. An exhaust system not adequately supported.
2. A major leak of exhaust gases from any part of
the system.
3. A catalytic converter missing where one was
fitted as standard.
4. A silencer in such condition, or of such a type,
that the noise emitted from the vehicle is clearly
unreasonably above the level expected from a
similar vehicle with a standard silencer in
average condition.
5. An exhaust tailpipe positioned so that fumes
are likely to enter the driver’s or passenger
area.

Section 3 applies.

Once again, a Diesel is subject to a smoke test.

For the full version, look here:-

http://www.motinfo.gov.uk/htdocs/

Hi Coco if you look at the method of inspection the method of checking is only concerning petrol engines so you do not have to check if a cat is present on a diesel.A friend of mine who is a mot inspector says that a lot of garages wrongly fail diesels because of the way it is written but he assures me that this is the case.

[Barkas]

Car went in for test today ( Sat 28th) and passed, MOT inspector says you can still leave the Cat of a Diesel, but not a petrol even after the introduction of this years new rules...... Fandabydozy. thanks for all the responses and help here folks.

[Arfcollins]

Excuse my ingnorance, but does removing the cat give some advantage?

[polar]

Excuse my ingnorance, but does removing the cat give some advantage?

may give slight bhp advantage but in the real world very little on a standard engine.

the only time to remove a cat is when it needs replacing as removal is cheaper than replacing.

[Ol'Jeffers]

.......or you can remove it from a diesel to keep it in good condition
for when the regs change again and they decide that, in fact, diesels
need to have the cat fitted too!! Then you won't have a knackered cat
for many thousands of miles! It also prevents the theft of your cat
from the vehicle while parked which now seems to be a national sport!