Hello,
The intakes of my 500E is suspected to have carbon desposits by the diagnostic computer. To fix this problem the dealer said the head has to be removed. This is an expensive affair, I'm looking for other methods of decarbonize the intake. I heard that a mist of water introduced in the intakes (but how?) can help loosening the carbon. Is this a myth? Suggestions and comments please.

Thanks

Remove the heads? I have a bridge for sale--good used condition.

Run a few cans of techron through it. Also buy good gasoline and change the oil a lot more often.

Remove the intale manifolds as a last gasp measure to clean them and valve pockets if you are unalbe to use spray claeners into the individual port runners. But no removal of cylinder heads is needed--never.

I'm going thru this and have considerable experience. My car's been on the most sophisticated diagnostic equipment in the land, operated by the best tech in the region (per MBZ, and the owner of a 500E) as well as the regional factory tech. My car, at like 1,400 RPM retards one cylinder, and one cylinder only. Further, upon acceleration it feels a bit peaky, not very linear. It used to idle very rough at first in the a.m. (sure sign of carbon deposits)but I've since treated it with BG's "44K"...considered by many to be the best, far better than Techron. However, it's tough to get. And it's best when injected directly into the fuel rail.

My car's first 4-5 years were spent, believe it or not, as a private limosine! It went about 4k/year, and they were easy miles. But they were perfect for collecting carbon, which I am now dealing with.

I'm gonna do the direct-inject BG program next, and will advise on my results.

Regards, Michael

'92 500E)

You can find 44K at small repair shops. Call around. It is the only one that I have heard that actually does something other than remove dollar bill deposits from your wallet.

Try a good old fashioned "italian tune up". Take the car out on a highway with some moderate hills and open her up. Occassionally, slow down and shift to a lower gear, then hit the gas. Allow the engine to rev really high (I don't know about you but in my normal driving the engine never revs above 2500). Get it up over 5000 (not in the red). The up shift and drive some more. Do this several times, driving at high revs in 3-5 minute bursts, going up moderate hills, etc. I had trouble passing an emmissions test. The dealer said it was due to build up of carbon, and they wanted to do a motorvac. I did this instead and passed the inspection. Change the oil afterwards of course.

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Jason Priest
1986 420SEL

What about cleaning the air injection ports? What methods other than removing the heads and exhaust manifold to get to the air injection ports?

Thanks for your inputs.

In the old days guys would take the hose of the windshield washer, put into the intake, pull a good hill and give it a squirt or 2.
I never tried it, but have been told it does the job.

Jason,

As several members of this Forum will attest, my right foot is anything but light! Has had no effect, however.

Just drove 500 miles and ran RedLine's cleaner thru tank #1, and am on tank #2 with another brand of cleaner. Peakiness remains. Will advise.

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All the best, Michael
500E
300TE

I've seen an old timer mechanic do that trick to decarbonize big block chevrolets. He sprayed with a hose on about 1/3 and held his thumb over the end of the hose. He sprayed intermittently and didn't use very much water, but I saw steam come out the exhaust pipe. The car idled and ran much better after this. He did remind me not to use too much water though.

Regards
Jason McNeese
1986 300E 88k
1999 Crew Cab Dualie Chevrolet 7.4L