W126 300SE exhaust

[Hank the Tank]

Hi, I'm new to the forum (first post ). I have acquired a low mileage '85 300SE, originally a uk car running on LPG. Mechanically it doesn't need much. Exhaust is first on the list and it looks like the very first box is rotted. I can't find a diagram online for earlier models but the later ones refer to this as a catylitic converter.

Can anybody answer if the earlier cars had a Cat and if it can be removed?

 

[grober]

If your car has the single cam M103 fuel injected engine then it existed in two different forms in the S class when facelifted in autumn 85. In anticipation of more stringent German/US emissions the KAT form came with a catalytic convertor and the essential tuning [ compression ratio/timing] to allow it to run on unleaded fuel [ leaded fuel poisoned the catalyst rendering it useless] and the RUF type without a cat running leaded fuel. I would guess if your car can run unleaded you will have a cat?
If its got this switch it should have a catalytic convertor. Bear in mind also that that generation of CAT had secondary heat shielding round it and this can corrode away making its appearance quite tatty but the cat body itself may still be intact??

 

[Hank the Tank]

Thanks grober . That's a very comprehensive answer.
The car is in a storage so I hope to get there and look later, I did notice a red switch, centre bulkhead that is similar but red in colour and wondered what it was. The joys of learning a new model as an aMateus enthusiast !

I don't suppose you have any tips on getting on the manifold to down pipe bolts when there are no facilities to raise the car?

 

[grober]

EZL _ KAT indicates that you have a car with an O2 sensor and catalyst converter.

EZL - ECE indicates that there is no O2 sensor or Cat and is designed to run on both leaded and unleaded fuel.

 

[grober]

This video may help? You really need to get the car on a ramp to access the manifold to down pipe bolts via a very long very good quality extension socket with possibly a tickle from a welding torch from UNDERNEATH! . It so awkward to get at otherwise. A good exhaust fitting centre with experienced fitters will do this for you "for a fee" obviously- even if you supply the downpipes/catalytic convertor assembly yourself --- athough obviously they would prefer you use their products its not a deal breaker. Its perhaps worth a phone round locally to determine availability /price

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[Marku]

You can't remove the CAT as it is an automatic MOT failure. As to getting the box off with no facilities jack up and support the side the exhaust runs down and you can just about work on the exhaust reaching under. To separate the down pipe from the manifold is difficult. You might be lucky and it will come away easily with a tap after of course undoing the bolts but from my experience it doesn't. I ended up taking manifold and downpipe out the top.

 

[Hank the Tank]

Thanks fellas, here's a pic of the switch If I'm understanding it correctly Graeme it's set to Sensor. (Ignore the pine needles, it is literally a barn find).

It is actually the casing of the cat that is blowing so I will get the exhaust and rad (also pin holed) off the Donor car and get a local garage to fit them (The owner has a tasty w126 380SE in thistle green so he's sympathetic to these machines).

Marku the Video is pretty much identical to my system.

 

[grober]

The switch refers to fuel octane rating the S position for use with premium fuel [ 95+] and N for low octane fuel.[ 92]
It would appear from the switch EZL- ECE picture the car was originally supplied without a CAT but if your exhaust is like the video it does have one. As leaded fuel became outlawed then most cars were retrofitted as yours appears to be.

 

[Hank the Tank]

Ok, So the if the car originally had no cat does that suggest it doesn't have hardened Valve seats for running unleaded?

It actually has an LPG conversion and a JLM valve saver fluid system to match, which as far as I can gleen adds a fine mist of oil into the Plenum to help the valves. The car has only 143k miles on it and was originally UK then was exported to Holland where I bought it. I think the Cat may have been fitted by a P.O. in Netherlands to reduce the emissions for NL test and tax which was emissions related.

 

[grober]

Can't say for certain but with Mercedes thoroughness I think all these engines came with hardened valve seats from factory in anticipation of more stringent emission regs/unleaded fuel.

 

[Braincrank]

Hi, I'm new to the forum (first post ). I have acquired a low mileage '85 300SE, originally a uk car running on LPG. Mechanically it doesn't need much. Exhaust is first on the list and it looks like the very first box is rotted. I can't find a diagram online for earlier models but the later ones refer to this as a catylitic converter.

Can anybody answer if the earlier cars had a Cat and if it can be removed?

I've got a 124 '89 200E and it hasn't got a CAT

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