Help, 240d engine seized - PeachParts Mercedes-Benz Forum

CaptainG · #1 09-07-2016, 06:04 PM

I recently bought an excellent 83 240d manual with a seized engine. I have a spare 82 240d engine that runs good to swap in, but would like to fix the one I bought with 190k on odometer. Cannot turn engine with 24 inch pull handle on crank pulley. Removed valve cover: timing chain intact, cam and cam towers look good. Removed glow plugs and removed starter, still cannot turn over. Any suggestions on what to try next will be greatly appreciated.

Sugar Bear · #2 09-08-2016, 02:59 PM

240D with a manual...NICE!!!

Is there any...as in thousandths of an inch fore and aft movement in the crankshaft? Is there any rotation in the crank at all or timing chain deflection when trying to rotate it? If not then something is seized in the crank or the transmission. If there is some crankshaft endplay then maybe the pistons/rings are stuck to the walls, a valve is stuck, or the wrist pins are seized or the injection pump seized. Can you move the cam at all?

Did the engine and trans both have oil in them when you got it?

You may have to pull the injection pump and then the trans to continue the diagnosis.

Good luck!!!

leathermang · #3 09-08-2016, 03:12 PM

Well, you might as well pull it out of the car... and put it on a rotary holder...
so much easier to work on...
the nice thing is that the cost of things like pistons is so much less than on the turbo engines...
Why don't you go ahead and swap the good engine into the car.. so you can at least have that available while you study the other engine and how to rebuild it ?

charmalu · #4 09-08-2016, 05:02 PM

I picked up a 79 240D about 4 years ago with a seized engine.
The girl I bought it from said it just stopped on the freeway, and failed to go in a forward direction.

It ran out of oil because she did not check it. Learned a valuable lesson for sure.
I picked it up for $300. Shows 167K on the spedo, but we know how accurate the spedo`s are.

I pulled the head a couple weeks ago and sent it to a shop in Dallas, Tx. for a customer.
When I got it off the cam shaft looked good, turned smoothly, no scoring on the lobes etc...
Timing chain looked ok.
No cracks that I could see on the Head

I could not turn the engine before I removed the head, or after it was removed.
I soaked the cylinders with WD-40...all I had, and was out of Kroil
Just got in 2 cans of it and will soak it with the kroil to see what happens.

My guess is the Rod bearings are welded to the Crank.

I agree with leathermang, drop in your good engine, and in your spare time, take the sick one apart.

CaptainG · #5 09-09-2016, 09:00 AM

Thanks for the response. I can move cam a tiny bit till the chain gets tight, maybe 1 degree. Transmission is not seized.
Previous owner said engine seized day after oil change at a quick lube place. Oil is about an inch over full mark on dipstick but I don't see how this could seize engine.
I plan to pull vacuum pump, oil pan and injector pump next.

Sugar Bear · #6 09-09-2016, 09:21 AM

Pulling the oil pan would allow the main and rod bearings to be inspected. Mark and keep the bearing caps in order if you remove them. Overfilling the oil can allow the crankshaft to strike the oil causing it to foam. The foam will get pumped through instead of an oil that has not been aerated.

Keep us posted and good luck!!!

leathermang · #7 09-09-2016, 09:53 AM

Quote:

Originally Posted by CaptainG

...... engine seized day after oil change at a quick lube place. Oil is about an inch over full mark on dipstick but I don't see how this could seize engine.......

The foaming problems possible with really overfilling come in two modes...
First that pumping air along with oil can reduce the actual amount of oil and the pressure it arrives at the bearings.
Second that oxygen mixed into the oil will reduce its ability to lubricate the bearings. They have calculated the ' half life ' of the oil depending both on the temperature it gets to and the amount of oxygen incorporated.. This can happen with transmission oil also... even without overfilling... procedures like having to rock the car back and forth to get out of a hole by moving repeatedly from reverse to forward can reduce the effective life of the trans fluid to a very short time... enough that it should be changed as soon as possible afterwards..
There are charts where the half life , at temperature increments above a certain temperature, is reduced are shown.

barry12345 · #8 09-09-2016, 12:47 PM

Important to know if engine just seized sitting a long time. Or it seized while running.

Seized while running just put your other engine in. Simply put seized while running will usually mean really serious work. Now seized while sitting will not usually be too bad to get running again usually.

There are no absolute fixed rules in the above statements. Just in general that is the way it usually goes.

Your observed oil level means nothing as the first thing someone would do if the engine oil was observed low after an engine quit. Would be to add oil.

If you can talk to the last owner might help. They have nothing to loose by being honest at this point.

Junkman · #9 09-09-2016, 05:21 PM

I would put a 617 in it. They can be had for not much. Why not?

Charlie Foxtrot · #10 09-09-2016, 08:42 PM

In the early 80's a new 240D owner walked into my shop from the adjacent expressway. Said his engine seized while pulling away from the tollbooth. We towed it in. I cut the AC belt & it started right up. He got lucky. My guess is that you did not. BTW it was the dreaded GM R4 compressor.

All silliness aside, if it seized while running it likely isn't worth the effort or cost to rebuild. Pull the use able bits and use the rest for a modern art sculpture. On the other hand, if you are learning automotive machining & repair it would be an excellent teaching aid. It's just ridiculously expensive to buy all the bits that get destroyed by lubrication related failures. Good luck.

leathermang · #11 09-09-2016, 09:16 PM

Charlie F, LOLOL