E34 catalytic converter cleaner

[Kamz e34]

Hello
Has anyone used catalytic converter cleaner from liqui moly on e34? My catalytic converter have never been cleaned. I was thinking of using it. Does it work?

[E34 Lives]

If it ain’t broke 🤣😂 ….. these cars are pretty up there in age … the comb structure in the catalytic converter can get brittle …. and concern is that it gets clogged …. I found driving on freeway for prolong periods, 2 hours or more really cleans them out, enough heat and higher constant rpm pressure does the job.

I found best maintenance is replacement of all engine gaskets around the manifold and the PVC plate. The key one is the back manifold PVC plate and gasket that has a diaphragm to prevent oil from being introduced into ignition system through the manifold. Also clean out manifold of oil residue. I would also change spark plugs to ensure good spark. By doing this on a regular basis you will attack the source (oil in ignition) that can foul up your spark plugs leading to poor ignition, which will result in oil and excess un-burn fuel from fouling up your catalytic converter.

A catch can PVC delete set up would solve much of this problem, but in my state (California) these are not allow under emission regulations. A setup like this would allow you to capture the oil in the catch can for removal and prevent oil build up in manifold in the first place, not to mention having a much smother running engine.

As for liqui Molly, I have recently started using their cleaners and additives, but don’t seem to notice any difference …. still reviewing these additives and cleaners …. they are reputable company and I will continue using their products for my oil change.

Happy Wrenching!

[shogun]

The cats on my 1988 E32 750 are 34 years old now and I still pass the strict bi-annual emission check in Japan. Never used a cat cleaner. These cleaners might do a good job of mitigating carbon deposits in a fully functional catalytic converter, but don’t expect them to revitalize a damaged one that is well over the 100K miles mark.
I do the same like E34 Lives to keep the cat in good condition: ... driving on freeway for prolong periods, 2 hours or more really cleans them out, enough heat and higher constant rpm pressure does the job.
I also change the lambda sensors after abt 60k miles, these sensors are important. The cat converter is monitored by the on-board diagnostics. If unburned fuel enters the exhaust gas, this can damage the catalytic converter.
Lambda sensors measure the oxygen content in the exhaust gas.