cylinder head replacement - Page 2 - PeachParts Mercedes-Benz Forum

benzdude42 · #16 03-14-2013, 01:55 AM

hey, do the 300d heads get those little cracks often? i have a spare head but haven't looked that close at it before and am a little worried

whunter · #17 03-14-2013, 02:09 PM

Quote:

Originally Posted by benzdude42

hey, do the 300d heads get those little cracks often? i have a spare head but haven't looked that close at it before and am a little worried

The only way to verify is to clean and inspect the spare cylinder head.

.

benzdude42 · #18 03-14-2013, 04:39 PM

Update. I was looking around the intake and exhaust manifolds today when checking the oil and it looks like its leaking oil from the head gasket. Would it leak oil before coolant on that side on the motor? There was a good size puddle under the exhaust manifold on some metal plate.

whunter · #19 03-14-2013, 09:55 PM

Quote:

Originally Posted by benzdude42

Update. I was looking around the intake and exhaust manifolds today when checking the oil and it looks like its leaking oil from the head gasket. Would it leak oil before coolant on that side on the motor? There was a good size puddle under the exhaust manifold on some metal plate.

It is the head gasket, they have many possible failure modes.
Be happy it is not dumping coolant into the crankcase.

.

benzdude42 · #20 04-04-2013, 02:46 AM

Head removal was put off, I got sick and lost my helper. I was wondering if my head gasket failed if my head would still get the oil it needed. I had the value cover off and some of the lobs had some wear marks and wasn't fully covered in oil. I also noticed that the timing chain had some slack and I could move it about a 1/4 to 1/2 an inch with my hand.

barry12345 · #21 04-04-2013, 01:50 PM

Just in case and for the time it takes. Disconnect the glow plug harness at where it joins the glow plug relay once the engine has warmed up. Put the ground lead of the meter to the engine block. Read the milli volts for each glow plug at the harness connections. Even though the glow plugs are older what you do not want to see is the number four glow plug at elevated milli volts compared to the others.

Do this when the engine has warmed up. If you get a higher voltage reading on the number four cylinder switch glow plugs and read again. Keep a record of what you are seeing. Only takes a 5.00 digital meter and they usually have a 200 milli volt scale.

You should have readings in the 6-10 milli volt area. For the limited effort required I would do this before taking the engine apart. Simply because by not doing it you could concievably tear the head off and find nothing conclusive since the issue was in the fourth elements calibration of the injection pump.

Just my two cents worth. It is usually correctable at home if this where to turn out to be the issue. I learnt years ago to never take an engine apart until I had exhausted all possibilities of locating what the issue is first.

Guessing later only happened once and I will never repeat than. The engine staying together with the same noise for ten thousand miles, with no change in the noise or engine performance including the same level of oil usage kind of eliminates some probabilities as well. These are just my opinions though. It is just a little too premature to rip the head off basically in my opinion as well or it would be for me.

Hard time being completly certain. The knock is not there with the injector installed and not being fuelled I have taken for granted. I had a little confusion when you stated it knocked with the injector installed. I have to asume you where fueling the injector at the same time.

whunter · #22 04-04-2013, 03:10 PM

Quote:

Originally Posted by benzdude42

Head removal was put off, I got sick and lost my helper. I was wondering if my head gasket failed if my head would still get the oil it needed. I had the value cover off and some of the lobs had some wear marks and wasn't fully covered in oil. I also noticed that the timing chain had some slack and I could move it about a 1/4 to 1/2 an inch with my hand.

Depending on where/how you are getting this slack..
Timing chain slack = tensioner, guide rail or chain failure are possible.

.

benzdude42 · #23 04-28-2013, 01:07 AM

Finally got the idle down on the motor and it sounds better. I'm pop testing the injectors this week and will balance them. I replaced them about 6 months ago and didn't pop test them thinking that I could get away with it.

benzdude42 · #24 01-29-2014, 03:49 PM

Does anyone think the head could be replaced with out a engine hoist? If two guys lift the old one off and new one on, while a third guy holds the chain.

barry12345 · #25 01-29-2014, 06:28 PM

How are you sure the noise is not occurring because of a timing error with the fourth injector? I would eliminate the chance of an advanced number four injection pump element in relationship to the others first still. May consume half an hour to do the test.

From your description you seem to need a new head gasket because of the oil leak I agree with incidentally.

Simpler=Better · #26 01-29-2014, 10:09 PM

Quote:

Originally Posted by benzdude42

Does anyone think the head could be replaced with out a engine hoist? If two guys lift the old one off and new one on, while a third guy holds the chain.

Two guys and a pipe can do it, it only weighs 120#. The third one can aim it. Using cutoff old head bolts to help guid things.

Quote:

Originally Posted by barry12345

How are you sure the noise is not occurring because of a timing error with the fourth injector? I would eliminate the chance of an advanced number four injection pump element in relationship to the others first still. May consume half an hour to do the test.

From your description you seem to need a new head gasket because of the oil leak I agree with incidentally.

2x exhaust all other issues before committing to a head job.

If the head comes off, expect to replace the valve guides and DEFINITELY pay to have it leak tested.

whunter · #27 01-29-2014, 11:24 PM

Quote:

Originally Posted by benzdude42

Does anyone think the head could be replaced with out a engine hoist? If two guys lift the old one off and new one on, while a third guy holds the chain.

I have done it alone.
Painful, difficult, dangerous, but possible.

With three people it is relatively simple.

.

vstech · #28 01-30-2014, 12:04 AM

Quote:

Originally Posted by Simpler=Better

Two guys and a pipe can do it, it only weighs 120#. The third one can aim it. Using cutoff old head bolts to help guid things.

2x exhaust all other issues before committing to a head job.

If the head comes off, expect to replace the valve guides and DEFINITELY pay to have it leak tested.

I've lifted the head off by myself... I fail to fathom it weighs 120#... full head with cam... I gotta go weigh one. ( I have a few in my shop...)

Stretch · #29 01-30-2014, 03:34 AM

OM617 head? Easy one man job I say (has to be a man though even if "he doesn't smoke the same cigarettes as me")

Rooster300SD · #30 02-02-2014, 02:33 PM

I just pulled the head on my 300SD so I can do my head gasket......again

The head without the cam weighs 77 pounds.
Tried to get some neighbors to help but no luck.
Probably getting ready for the Super Bowl.

I got it out by myself without too much trouble and I'm not a
big strong guy like Stretch.

I hooked a strong chain to the front and drivers side lift points.
grabbed the chain and one of the manifold bolts and, while standing in the engine bay, lifted it up onto a large board I had right next to the engine.

Now, when I put it back on, I'll get some help so I can ease it back on nice and straight. So far, I see no cracks, so I'm happy about that.
Off to the shop for a magnaflux and to make sure it's flat and try to figure out why that gasket failed.

Jeff