To CAT or not to CAT....

[mercw126man]

Can anyone tell me whether my late 1991 420SE 4.2V8 has a catalytic converter fitted? I'm replacing the Fuel Pump Relay (see earlier thread) and having some difficulty with the correct part number, as MB says it should have cats, but on inspection (admittedly without a ramp but they are usually fairly obviously spotted) I can't see them (one per bank I assume).

The part number of the relay fitted to the car is 003 545 17 05 which doesn't marry to any current (or superceded) part numbers for the car. The one they say should be OK from the VIN (but only for a catalysed car) is 003 545 25 05

As the part is non-returnable I'm reluctant to spend £130 ish on a useless part if wrongly identified.

Can anyone help please?

 

[Bolide]

Cats

The cat may be close up to the manifold and fairly invisible, or they may not be fitted, or they've been removed already. I think you'll find it came from the factory with them and they're still there

If the dealer says it had cats, and they checked it using the VIN number for the car, I'd believe them


Nick Froome
www.w124.co.uk

 

[television]

Reminds of the one hit wonder song by Twiggy (leslie Hornby) "here we go again" OK back to normal.

I understand you cant find your cat.
Your two down pipes go into 1 box and on to two pipes, these pipes have lumps in the middle and it then goes on to the rear box.
The Cats are the lumps in the middle, they stick out sideways. Effective 09 / 87

Malcolm
I can see nothing near the manifold and this was the first example

 

[mercw126man]

Malcolm,

Completely different from your description I'm afraid. Two seperate downpipes, which remain separate until the (made as one piece but) separate first silencers in front of rear wheels (marked with MB three-point star so its not aftermarket), then leave as seperate pipes to single back box, with twin exit pipes. No sign of cats at all. Presumably they only appear at the RSCPA at this time of year.

Still leaves me with dilemma as what do I order, right one for the VIN or right one for the car? Can anyone help from the part numbers as MB didn't know what 003 545 17 05 was intended to fit, other than it being a relay - we'd kinda worked that out for ourselves.

 

[television]

Can you please give me your Engine number type please ie 116 ?

Malcolm

 

[mercw126man]

Yes, its a 116.965. Seems someone might have changed the exhausts (minus cats) in the past.

 

[clive williams]

Yes, its a 116.965. Seems someone might have changed the exhausts (minus cats) in the past.

I don't blame them, the cats are not a legal requirement on your age of vehicle for the MOT and the costs in terms of driveability, fuel consumption, maintenance etc etc in my opinion doesn't justify their retention.

If your car had them originally fitted then what's happened to the O2 sensor(s) (lambda). If they're not fitted to the exhaust I would think that it would be a comfortable idea to order the pre-cat fuel relay

Clive

500E
E320CDIT210