Hello,

I am new here and a new M-B owner. I picked up a 1972 280SE 4.5 that had been sitting for 14 years in a garage. My hope is to get it up and running and use it just to cruise around in.

I'm in the process of getting the engine to function again. After dripping oil down the spark plug holes and valve covers I want to try turning the engine by hand. Since the crankshaft bolt is pretty well-recessed in the pulley/balancer can someone tell me what size the bolt is? Will I have to remove the radiator, fan and shroud to really get access to it? Or will a deep impact and a breaker bar, hopefully, be sufficient?

EDIT - I did a search on these forums and the diesel engines list a 27mm bolt. But I wasn't sure if it would be the same configuration as on my gas V8.

Thanks in advance,

Doug
Massachusetts

My M117 5.0 V8 out of a 1990 500se is also a 27mm bolt.

HTH, Martin

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1990 420SEL 217k Miles
1975 Chevy K10 400ci SBC power!
1995 Jeep Cherokee 4.0 Limited
1997 Suzuki GSXR750 SRAD
1989 Kawasaki GT550G4

be frozen in the cams.

and it might be worth trying to breakit loose with the starter for a while.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Sure. Frying the starter is preferable to fitting a socket to the crank bolt and being careful.

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1989 300 SEL that mostly works, but needs TLC

Well, you could carefully bump it with the starter, and I mean carefully and bump: one to three very short bumps to see what it does. Lube it up really, really, well first. Remove the cam covers and see what it looks like up top: be sure a valve is not stuck in the guide, etc. before. You may break a ring or two; typically the rings are the single greatest source of friction in an engine anyway, much more if rusted. Either warm the coolant and pour it backin the engine, or heat some water and put it in. Heats up the cylinder bores and expands them, maybe enough to get things loosened up. whichever cylinders have open valves could be the culprits.
I reinterate: proceed with caution.
Better yet, I take it back: don't do this. I might try it on my own in special circumstances,like if I knew I was going into it anyway, but it would be with thought.

As for the car: this could be a nice car, if you repair it properly. Have you seen the credit card (I think) ad on TV, where the answer was to throw money at the problem? I saw one of these pass through the local U-Pull salvage yard a couple of years ago; did not have a dent on it, no broken glass, and had all the wheel covers. I could not rescue it at the time; so sad.

Hi, thanks for the Replies. The heated fluid is a good idea and one I hadn't seen yet. Formula 1 and Indycar engineers used to do this when priming their engines (may still do it).

I may just bite the bullet and pull the radiator, shroud, and fan and get better access to the crank bolt. I feel a whole lot more comfortable turning this by hand rather than troubleshooting the electrical system if the starter doesn't spin (no battery at the moment).

Thanks again,

Doug

P.S. -- it may not be frozen. there was still a good amount of oil in the top of the valve covers and I may get lucky. I'd love to be wrong on calling it 'frozen'.

Using the starter is a risk. If this was a '82 Chevette then ok, but I wouldn't risk it on a handbuilt 280SEL 4.5. The last of the real good cars.

I doubt you are going to break the crank bolt. Unless you use a 3/4 inch impact on it. I would remove both valve covers and replace all of the plastic tubes that oil the cams, just to be safe. It wouldn't hurt to use some engine assembly grease on the cam lobes. I would drain the old oil out and change the filter also. Oil capacity is around 9 quarts. Pulling the plugs and soaking the cyls with a light oil is a good idea. I would also make sure that the rubber fuel lines below the air cleaner and leading to each injector are sound. Many a D-jet v-8 has caught fire because of fuel leaks here.