1975 230 gas- metallic screeching on acceleration, low power, and smoking exhaust - PeachParts Mercedes-Benz Forum

Eva Braun · #1 04-09-2007, 06:13 PM

Eva Braun, a 1975 230 gas model has been running smooth on Koh Samui for a year, but has recently developed a metallic screeching on acceleration. White smoke from exhaust. Power has dropped dramatically, oil and gas consumption are elevated. Suspect piston rings on at least 2 cyclinders are shot; how can this be verified? Is replacing rings viable? Would a rebore be required? Local mechanics in Thailand have limited experience and communication skills, but recommend replacing with a Japanese engine, which I would rather avoid. Have only replaced spark cables, which were completely corroded. Checked distributor cap, which showed high resistance on all 4 points, due to corrosion, which will replace tomorrow, but fear this will not suffice as a fix...

meltedpanda · #2 04-10-2007, 10:22 AM

you could pull plugs and check compression, take off valve covers and look for the obvious

WANT '71 280SEL · #3 04-10-2007, 11:04 AM

Could the noise be separate from the smoke and oil consumption? I ask because it sounds like you may be describing a slipping v-belt. Are you sure that the noise is related to the smoke, etc.? If they are related, then follow meltedpanda's advice.

Thanks
David

meltedpanda · #4 04-10-2007, 02:45 PM

David is right, could also be water pump going south, Gen/Alt bearings
If is has AC - idler pulley
So many items capable of screeching

but not all associated with power and fluid loss

Eva Braun · #5 04-11-2007, 05:19 AM

Thanks for your advice Melted Panda and Want '71! The AC unit is also working very poorly in the tropical heat; thought the coolant level may be down... The screeching is only evident on 'rapid' acceleration, particularly at low revs, and seems to be engine related; possibly the drive chain? Haven't yet looked inside the engine... Will try changing the distributor cap and spark generator coil first. Local mechanics say (I think) that pistons 4 and 2 are "no good", and leaking oil through the rings. Disconnecting these 2 pistons from the spark plugs seems to affect the engine very little at idle. I'm guessing that the white smoke is a result of the oil leaking through the piston rings. Engine is running VERY hot, which also makes me think that there is a lot of resistance, presumably from the pistons. Some old Germans on the island have commented that the timing is off, but can't communicate this to mechanics here... Any ideas on which direction to take would be much appreciated.

meltedpanda · #6 04-11-2007, 10:16 AM

if you remove the wires and nothing happens it could possibly be spark related
Unfortunately all the symptoms you describe would not be due misfire.
You could have a cracked head causing fluid loss into the pistons and thus the white smoke.
I am afraid to say you may have serious issue

Eva Braun · #7 04-13-2007, 08:17 AM

Thanks Melted Panda. Power continues to decline, with more pronounced metallic grinding on acceleration, and Eva has now started to backfire, particularly when reducing power. Guzzling gas at more than twice the normal rate, which would also seem to support this theory. Got to admire her stamina! Guess this means that fuels in at least 1 cylinder is not being ignited? She seems to be running on only 2 cylinders, and while I don't doubt that there are serious problems with the pistons, I'm still hopeful that upgrading the ignition system will resolve the lack of firing. Failing that, will have to face rebuilding the engine, which none of the local mechanics are willing to attempt. No tools, expertise, or workspace, but would have liked to get to grips with the job myself. Perhaps I can twist someone's arm to pursue a joint venture; are piston rings/heads/other required components compatible with later models/other manufacturers?

meltedpanda · #8 04-13-2007, 10:41 AM

there are a lot of parts around for these ol engines. Perhaps if you can't fnd them there we can ship them from the US. Not sure about intercahnge of parts, but I do know these engines are pretty straight forward for repair

dieseldiehard · #9 04-13-2007, 11:32 AM

Eva Braun, sawasdee Krab!
Its too bad you didn't have this misfortunate a few years earlier, I scrapped out a 4 cyl gas engine when the tranmission in my '75 230 went bad.
I removed the head and sent the rest of the engine to the junk yard. I traded the cyl head last year to Khun Peter Schmid.

Aluminum heads tend to get corroded in this car (and others) if the antifreeze isn't replaced every 2 years or so. Hopefully you don't have a bad head, is the exhaust sweet smelling (of antifreeze?) or does it smell of oil?

I saw a 230.4 in Bangkok in about 1999, the last time I was there (I will be there again in October of this year) and it was in remarkably good condition. There's somthing about a RHD Mercedes that makes them look more desirable, maybe because we only have LHD cars here in America.
Oh, if I were in your situation I would find a 240D and put it in there, surely there must be some 115 chassis diesels around or have they all been used as donors for long tail boats. I took a tour up the river Quae in a longtail with a 5 cyl diesel in it.

Eva Braun · #10 04-14-2007, 03:40 PM

Thanks Melted Panda and Diesel Diehard! Don't use antifreeze on Koh Samui, but the smoke is rampant. Have decided to overhaul the engine, and looking for new piston rings; does anyone know the standard size on this model, or good sources to buy from?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode