My dealer, Greanoaks Slough, tells me that my Cats are rattling (I can't hear it). They tell me that when the cats break up then the engine will ingest the particles severely damaging the engine. The local shop around the corner tells me not to worry until are really loud. Thoughts? Is Greenoaks trying to rip me off? My 2001 C32 has 93k miles.
The cats are downstream of the engine and if they break up all the bits go backwards towards the tailpipe ie away from the engine.
They can also block but this would cause low power.
I would go with the second garages opinion and ignore them until they are obviously failing, or fail the mot.
Lynall
They can also block but this would cause low power.
I would go with the second garages opinion and ignore them until they are obviously failing, or fail the mot.
Lynall
mercedescl500
Active Member
I agree.
I agree, when a Cat breaks up its most likely going to hit the car behind you if you rev the engine hard enough
, mine on the CL were bad for awhile before I could hear the sound (sound like bearings rattling inside a soft drink can) then I just cut them out and effectively eliminated them. Which cats are bad ? my car had 4 of them (primaries and secondary). If your main primary cats are going bad then some say you will lose power as Mercedes engines require the primary cats to create a little extra back pressure. (this info on the cats needed to create a little back pressure was adapted from a cl55 kompressor thread, I could be completely wrong when it comes to a C32). Personally as Lynall said, don't worry too much. If they do go bad/have gone bad then now is the time to get some high-flow 300cel cats (OBDII Compliant so you you don't get a CEL thrown)
I agree, when a Cat breaks up its most likely going to hit the car behind you if you rev the engine hard enough
, mine on the CL were bad for awhile before I could hear the sound (sound like bearings rattling inside a soft drink can) then I just cut them out and effectively eliminated them. Which cats are bad ? my car had 4 of them (primaries and secondary). If your main primary cats are going bad then some say you will lose power as Mercedes engines require the primary cats to create a little extra back pressure. (this info on the cats needed to create a little back pressure was adapted from a cl55 kompressor thread, I could be completely wrong when it comes to a C32). Personally as Lynall said, don't worry too much. If they do go bad/have gone bad then now is the time to get some high-flow 300cel cats (OBDII Compliant so you you don't get a CEL thrown)
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Hi,
If the upper CATS are breaking up there is a chance that parts of the CAT can get sucked into the engine causing damage i believe some cars may of even been subject to a recall to change them, what exact models this effected i,m not sure.
Ask them which CATS are breaking up, upper or lower ones.
If the upper CATS are breaking up there is a chance that parts of the CAT can get sucked into the engine causing damage i believe some cars may of even been subject to a recall to change them, what exact models this effected i,m not sure.
Ask them which CATS are breaking up, upper or lower ones.
Depends on the cam timing - in particular the overlap at the top of the exhaust stroke when both valves will be slightly open at the same time (see here). At low throttle opening (and on cams with more aggressive timing) the momentum of the airflow (in the manifolds) may not be enough to maintian flow in the correct direction and some reversal may occur - this is why you get a poor idle with race cams.
On a road car this is unlikely, but not impossible, especially if the car is running badly/misfiring.
and having an aggressive cam would be a bmw thing.
AndyPCD
Registered User
Hi
I have seen a couple of engines damaged by the cats breaking up but these are only when the top cats break up so as said i would get the dealer to be a little clearer about which one is rattling also which side as i doubt both would be rattling
I have seen a couple of engines damaged by the cats breaking up but these are only when the top cats break up so as said i would get the dealer to be a little clearer about which one is rattling also which side as i doubt both would be rattling
