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240d blowby
Getting significant blow by in my 74 240d... Recommendations? There is blowing passed the oil cap also oil filling up in the air filter housing
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#2
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Run straight 40 grade oil for the summer. Should cut it down. Add a quart of miracle mystery oil to the oil change as well not overfillng the oil level. You want to see if the rings can be cleaned up a little. Or if it is too late. If the engine has been run on wvo I wouldd suggest a more aggressive treatment.
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That'll help reduce the symptoms but not really solve the problem.... Thanks for that recommendation, and I'll do that today, but any ideas on solving it?
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#4
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I'd like to start by saying I'm new here, so take my advice with a grain of salt. If it's pooling in the air filter housing that's pretty bad haha. The only way really to fix this is an engine overhaul, but financially you're better off finding a junkyard engine. If you are up to the challenge you could just throw some piston rings in it, but you get out what you put , so it's not a real fix. You should do everything if your going to bother. In the mean time use a few bottles of Lucas oil stabilizer and thicker motor oil. Replace oil cap gasket, less mess lol.
Last edited by AwfulMechanic; 06-27-2013 at 12:35 PM. |
#5
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Lol... Thanks... So the consensus is to use thicker oil until I take the top end apart basically..
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#6
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You need to measure the compression to see how bad or otherwise is the engine. Blow by normally is caused by low compression; worn cylinder or coking of the rings. Soaking with MMO is not going to cut it if the coking is bad, definitely not with worn cylinder. Thicker/heavy oil is a band-aid.
I have rehabilitated a OM603 engine with terrible blowby by removing the head and oil pan, pushed out the pistons from the bottom. Soaked the piston in solvent to remove all the carbon coking. Lightly honed the cylinders and then put the rings back in. I replaced all the oil rings as some were broken when I pushed the piston out. I reused the top rings. The compression was 50psi before and they were 260-300psi ( measured cold ) across all cylinders after the mini overhaul. It was all done with the engine in car. I have done 7K miles on the engine after the overhaul and it is running like a champ. No blow by to speak of. It is using a quart of oil per 1K mile. It is acceptable to me as the engine has 349K miles. I could not have done it without the help of this forum as I am not a heavy duty engine guy. It is a lot of work but it was a fun project for me. It does not beat playing golf but the satisfaction you get after fixing the engine is priceless. This is my experience and it works out well for me. Good luck.
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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed. W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html 1 X 2006 CDI 1 x 87 300SDL 1 x 87 300D 1 x 87 300TDT wagon 1 x 83 300D 1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry. |
#7
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Are you sure it's all blowby? When my 240D started putting oil in the air filter housing, the cause was a perforated diaphragm in the vacuum pump. It was pumping oil into the air filter housing for a while before the brakes started feeling hard.
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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar. 83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles 08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles 88 Jaguar XJS V12 94,xxx miles. Work in progress. |
#8
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Need a video to give meaningful advice. But I agree it could the vacuum pump.
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1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13 |
#9
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Before you change the Oil you can dump something like Marvel Mystery Oil into the Cylinders (on by way of the Glow Plugs or Injector holes; if the Injectors you can pool more inside but have to replace the Heat Shields) and let it soak for a week. Rotate the Engine and repeat.
Crank the Engine an blow out any excess left in the Cylinders. Do the Oil Change and go for a hard rid on the Freeway. If load up with some of your heavier weighted Friends for the ride. The Goal is to free up any sticking Piston Rings. Others have said that switching to synthetic Motor Oil will do that same after about but it take about 200-300 miles to get the results. Again, this only works if sticking Piston Rings are the cause. Other wise Blow-by is just nuisance unless so much pressure builds up that it effects the Vacuum Shutoff of your Fuel Injection Pump or blows out a Seal
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84 300D, 82 Volvo 244Gl Diesel |
#10
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Also do a valve adjustment and start driving hard....adjust the valves again....drive hard again and keep repeating.....a lack of valve adjustments in the life of the vehicle can cause blow by......my theory is that when the car doesn't receive the recommended valve adjustment carbon builds up on the valves....thus the valve can't seal thus allowing compression to escape....becomes blow by....once the carbon starts chipping away the valves become tight....I have been doing a lot of valve adjustments on my car sometimes only after a couple hundred miles....the exhaust valves are always tight and the intake loose....
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#11
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Quote:
I also agree that a good used junkyard engine is a better and cheaper option usually than really getting into these engines seriously. That's unless the rings are just stuck. It usually takes some time and miles if the solvent is going to have any effect. Still the solvent may loosen them back up over time if they are compromised in that way. Nothing simple of course is going to undo serious wear issues. |
#12
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Quote:
__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed. W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html 1 X 2006 CDI 1 x 87 300SDL 1 x 87 300D 1 x 87 300TDT wagon 1 x 83 300D 1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry. |
#13
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I can see where cooljjay is coming from. If you believe poor combustion causes sticking Piston Rings then keeping the Valves Adjusted correctly supports good combustion and helps prevent sticking rings.
Replacing bad Hydraulic Lifters on Engines that have them is the analogy to adjusting the Valves.
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84 300D, 82 Volvo 244Gl Diesel |
#14
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If your air filter is like mine (1968 220d), it is supposed to have oil in it. Is your air filter housing actually "filling up" with oil or just has some oil at the bottom? If it is truly filling up, that is too much oil to come from blowby, but probably means you have a busted vacuum pump diaphragm or a busted injection pump diaphragm.
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1968 220D, w115, /8, OM615, Automatic transmission. My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear). |
#15
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Quote:
On my euro, I actually managed to cure the blow by....by doing repeated oil changes and valve adjustments....I was shocked to open the oil cap and see no smoke... I am glad some else is seeing my theory....
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