240D Finally Done ?

[sgoodhart]

Hi everyone,

My 1981 240D would not start once the temperature went to 40 degrees F or lower at night. The Glow system and battery/cables are both fine. Finally jumped it on Saturday after the weather warmed up and after repeatedly trying. It took awhile for it to turn over fast enough to start. I took it in to a shop to have a compression test done. The shop checked the valves (two were a little tight) and then told me that a compression test would be wasting my money because there was so much blowby out of the Cam Cover hose that they could tell it was a tired engine. Short of major engine work I thought I would ask your opinion. Do you think that replacing the starter with a heavy duty one and changing the oil to Mobil One would make a big difference and allow it to start ? I use a long glow cycle to start. Once started it runs well, it just does not turn over fast enough or long enough when cold. A block heater would not be practical since I have no place to plug into where I park it at work. At home it would be no problem. Lowest temp I experience is about 20 deg F.

Thanks.

[kerry]

Blowby is not a good measure of the health of these engines. Some of them put out a hell of a lot of smoke while still running well.
Synthetic oil will make a big difference in cranking speed at low temperatures. I have also found that the heavy duty turbo starter turns the engine over faster at all temperatures.

Whether this will solve your problems, I don't know.

What do you mean by 'not turning over long enough'? This sounds like a bad battery to me.

In a pinch, a small shot of ether (starting fluid) might solve your problem. If you're looking to rebuild the engine anyway, I wouldn't hesitate to use some ether on an occasional basis.

[Fisherman]

My 240 sounds like "a freight train running at full throttle" when you pull the oil filler but it just started at 16 degrees yesterday. Does not burn any oil between oil changes and drives like a gem.

Personally if I want to know the health of the engine I run the tests. Compression being just one of them but it can tell you if it is one hole or all 4 that are getting tired or having problems. Depending upon the results of the compression test you can go further and do a leakdown and try to isolate top end or rings.

I just went through my top end on a budget at $250.00 and am very happy with the results. If all 4 cylinders were down on compression then I would not have even considered this project.

Sounds a little like your starter is going or your battery is going. It takes a good amount of juice at these cold temps to glow and then crank a motor at a decent speed and if the battery is getting tired this cannot be accomplished.

[sgoodhart]

Kerry,

What I meant by not cranking long enough was that when cold I cannot get the engine turning fast enough before the battery runs down a bit. That's why I wondered about putting synthetic oil it it. When the outside temp is warmer or when engine is warm it turns fine. I had the battery load tested and it tested fine. You make me wonder about the starter though.

[dreamliner77]

Definitely sounds like you need a new battery.

Get one, then you can crank a little longer and it will probably turn over.

[H-townbenzoboy]

Your 81 240D is exhibiting the same problems that my 81 300SD is, with the blowby, and the difficulty in trying to get it started in cold weather. I would not worry about blowby unless your car starts using alot of oil. I would say have a compression test done to see if it's low compression. I just had my valves adjusted, and I'm getting a compression test done soon to check it out.
BTW- If you have low compression, what are other ways can it be fixed without paying the indy an arm and a leg to fix it?
-Joe

[sgoodhart]

Joe,

Other than doing a ring job I know of no easy way to fix a compression problem. I think the real issue is how low the compression is, and whether it is fairly even across cylinders. I'm really trying to figure out if I might be able to get through the cold weather without having to do a ring job. I don't really want to install a new starter if it's not going to do any good.

Scott

[Rick Miley]

Get yourself an Optima battery. It'll spin that thing like a toy.

[leathermang]

You are jumping ahead too far... you know nothing until you have a good battery, good connections to the starter, and strong starter to turn over the engine fast enough to EITHER start it or do a good compression test...
Go back to basics and get those conditions set up before you start worrying.

[sgoodhart]

Thanks for all the input. I am going to focus on the starter and double ckeck the battery and see if it helps.

[mplafleur]

I kept farting around with different batteries trying to improve the start on my old '75 300D. What made the difference was changing the starter when it finally gave out. I didn't know the motor could turn over that fast, and boy did it make a difference in starting the car.

I changed the starter on my '80 240D over Christmas. It now starts on the first crank. I bet you couldn't cycle the key quick enough and not have it start. It's that fast. I replaced it with the heavy duty 300D federal version. From Fastlane at about $133.

[sgoodhart]

Thank you Michael. I think I will try the starter. My understanding is that the heavy duty version from a 85 300D will fit the 81 240D. Is that what you used ?

Scott

[mplafleur]

Yes, here's a clip from my Fastlane order confirmation.

Description = Starter
Brand = Bosch
Part number = F5000-11370
Quantity = 1
Price each = $134.75
Core charge = $60.00

Mike

[sgoodhart]

Thank you Mike !

[Rick Miley]

240D Finally Done?

Actually, yes. Your 240D is done. I'll give you $100 for it.