240D valve adjustment questions - PeachParts Mercedes-Benz Forum

ericnguyen · #1 04-14-2003, 04:54 PM

Dear friends:

When you prepare to do valve adjustment on a 240D (1981):

1) Do you have to remove both the radiator, fan shroud and fan in order to access and rotate the crankshaft using a 27 mm socket and ratchet drive?

2) Is it possible to just remove the fan without removing the fan shroud and radiator? I don't want to remove the radiator because it seems hard to remove the oil cooler from the radiator.

3) The radiator drain hose on my 240D is made of some blue plastic, and its neck got broken when I tried to turn it in order to drain the coolant. What should I do to fix it? (just drill through it and replace with another drain plug?

4) I also tried to rotate the crankshaft (and hence camshaft) by rotating the power steering pulley bolt. However, I could only rotate it a little bit before it became very hard to turn (so I stopped because I did not want to destroy the power steering pump). Was it because of the high compression in diesel engines?

Thank you in advance for your help.

Eric

rwthomas1 · #2 04-14-2003, 05:10 PM

Do a search on adjusting valves, there have been many posts on this topic. I don't know about 240's but I was able to get a socket on the cranshaft bolt pretty easily on my 300D so I would be very suprised if you can't do it on a 240... RT

engatwork · #3 04-14-2003, 05:36 PM

Eric - you shouldn't have to remove any of that stuff to adj the valves.

#4 04-14-2003, 05:44 PM

You won't destroy the power steering pump by turning
it by hand. As long as you have the correct size
socket so the nut won't strip you can turn it to
position the camshaft for valve adjustment.
This was the method I used, when the belt
slipped due to the high compression I applied
pressure to the belt by hand while turning
the nut with a wrench. I'm sure this is not the ideal
method but it is a labor saving one if the
alternative is to remove the radiator for
no other purpose than turning the crankshaft bolt.

leathermang · #5 04-14-2003, 07:47 PM

Listen to RT and Jim.... you may have to put the socket on and then attach your ratchet if it is close quarters...
It is a bad idea to use the powersteering pump nut to turn the engine because you can get it so tight that you will have trouble getting it off when you need to... and it can be stripped... just no need to take the chance...
How tight can it get you ask ? The PO of TCane's car had done that and it took two heatings with oxygen/acetelyne and shock cooling plus a big hammer to get it off... it clamps the pulley down onto a taper...

Edit, I do know how to spell listen... so much for proofreading ...

300SDog · #6 04-15-2003, 07:21 AM

>>>....tried to rotate the crankshaft..... I could only rotate it a little bit before it became very hard to turn .... Was it because of the high compression in diesel engines?

Let me guess, you have NOT removed or loosened the glow plugs to prevent cumbustion chamber from building pressure?

#7 04-15-2003, 07:43 AM

You don't have to remove the glow plugs or anything to turn the engine for valve adjustment. Unless there is catastrophic failure that causes engine lock up, you just need to turn, and if it's too hard for you, give it a few seconds for the compression to bleed off.

The four cylinder is very easy to access the crankshaft bolt. You will need a 27MM deep socket or a 27MM socket and very short extension.

Ditto on leathermangs suggestion about not using the power steering bolt to turn the engine. This is a BAD idea.

Good luck,

#8 04-15-2003, 10:33 AM

I have tried rotating the crankshaft bolt and didn't care for that method at all. What I do is jack up a rear wheel, release the emergency brake, put the car in fourth and rotate the rear tire by hand until the valves are in the position I want, a very easy operation for me. I have also hooked up a remote starter and jogged the engine to get the valves in position too, but I like the rear tire method better. Ths is with a manual transmission BTW.

Len
'83 240D 335,000 miles

franklyspeaking · #9 04-15-2003, 02:13 PM

On my 1982 240D access to the crank bolt is pretty much impossible....in fact I can't even get my hand between the plastic fan shroud and the engine. I just jog the starter to adjust the valves. I don't think you have to have the cam lobes pointing exactly 180 degrees away from the valve to get an accurate adjustment. It usually only takes 3 or 4 jogs to get a reading on all of the valves. You just have be careful to keep track of the ones you have already done, because with this method the adjustment order will be random.

My $.02 worth.

#10 04-15-2003, 05:04 PM

I'm totally taken aback! I guess my four cylinders have been different. Turning mine with a ratchet and 27MM injector socket is as easy as turning a lug nut. The fan is slightly in the way, but you just turn it a little and go for it.

Have a great day,

franklyspeaking · #11 04-15-2003, 05:23 PM

It's the fan shroud that blocks access on my car. You could take it loose, but you can't remove it without taking off the fan. I take the fan off by unfastening the shroud and orienting in such a way to gain some room to get to the fan screws. Once the fan and shroud are removed you have six inches of space between the engine and the radiator. But it's not worth all that for a valve adjustment. I suspect other years and Euro versions may have had different fan shrouds????

engatwork · #12 04-15-2003, 06:17 PM

If I remember correctly I have been successful in getting the 27 mm socket with a breaker bar on the crank bolt on the 240D. I do remember that it is harder to do on the 240D than the 300D though. This may be the only job harder on the 240D than the turbo 300D. Wouldn't you agree it Larry

.

190D22 · #13 04-15-2003, 06:20 PM

I'm very glad I don't have mechanical lifters!

ericnguyen · #14 04-15-2003, 06:27 PM

Dear friends:

I'm completely in d'accord with franklyspeaking regarding accessing the crankshaft bolt without removing the fan and then the fan shroud. On my 1981 240D, I did actually have to remove them before having some space to stick the 27mm socket to the crankshaft bolt and rotate it using a long breaker bar from above.
LarryBible and engatwork must be lucky enough to have some specially "altered" 240D cars that provide easy access to crankshaft bolts :-)

I did not have to remove the glow plugs or injectors.

240DieselDog: did you actually move the stick shift to NEUTRAL?
It's very easy for me to turn the crankshaft clockwise with a breaker bar. I do not think diesel engines' inherent high compression is big enough to counter the torque of your ratchet drive or breaker bar.

I like sokoloff's smart rear tire method and will apply it next time. Be sure to turn your rear tire in the forward direction if you put your manual transmission car in fourth gear.

Thank you all very much again.

Eric

JimSmith · #15 04-15-2003, 08:24 PM

Eric,

I have a "standard" edition 1982 240D and have no real problems getting a 27mm socket and a short extension on a 1/2" ratchet to turn the crank. I put the extension on the socket and fit that to the crank fastener, and then put the ratchet on, all from above.

That said, I did this job (valve adjustment) on my Father-in-law's 1980 240D while up at the family camp at Lake Champlain a few years ago, and did not have a 27 mm socket. So, I parked the car facing downhill (on a very slight incline), put it in gear (4th) and just pushed the car to move the valves, then used a stone to block the wheel. It worked so well I do that way most of the time. I will confess I have used the power steering pulley fastener a few times too. Anyway, the push the car method gets the job done in about a car length. I push it back in neutral, and check in another car length, just to avoid dragging my tools down the driveway.

So, unless you have the forearms of Popeye, or grizzly bear claws for hands, or both, there is no real reason you cannot get a socket on the hex at the end of the crankshaft to turn it. It should also be noted though, there are a number of other means as well, many of which are practical and technically sound. Good Luck, Jim