300D overheated and blown head gasket...What to do? - PeachParts Mercedes-Benz Forum

Rolson · #1 01-03-2013, 11:25 PM

Hey guys,

Recently I was driving down the expressway when I realized I had no heat in my cab. My temperature gauge does not work, so prior to not having heat, I did not realize I was overheated.

I pulled off the freeway to look things over, and it stalled at the end of the ramp.

After letting it cool down, and having it towed to my parents farm where I have a shop to work on it, I added coolant and water. When I cranked it over, I blew it everywhere, but mostly out the passenger side.

I do not have any coolant in the oil pan, but I do know at least the head gasket is blown.

So far I haven't begun to do anything with it as we had to finish getting our new house ready to move into before Christmas.

I have never seen an engine get as hot as this one was, so I am at a loss as to what else I might be in for once I start to tear it down to replace the head gasket and bolts. Any advice, tips, warnings, or red flags I should be keeping my eyes peeled for when I get at it?

I will be looking for any obvious cracks in the head, and block, but I'm not sure what caused it to lose the coolant in the first place.

The engine was thoroughly cleaned last winter/spring. It had very badly leaking seals at the front and rear of the crank. I installed new head gasket kit, and bolts, and crank seals. Finally had everything running well, and was getting around 28-30 mpg in my travels up and down the freeway. I had put about 8000 miles on the engine since I did all that work, with no indication of any problems when this happened.

Thanks for your help.

Rick

Ozarkdude · #2 01-04-2013, 01:51 AM

I would drain the block, remove the injectors, and crank it to clear any water/coolant from the cylinders. Then pour a bit of MMO down the holes, crank it with a rag over the holes a bit, and screw the injectors back in until you can work on it.

Ive seen some really blow, tons of white smoke, blowing out through the radiator, and it was just a head gasket.

No sense in guessing what youll find. Pull the head and youll be able to clearly see whats going on.

Rolson · #3 01-04-2013, 10:16 AM

Thanks for the suggestion.

I will get the MMO in there asap.

I need to finish the four page punch list on our house before I can take the time to tear into this engine. Wish I would have thought of this sooner.

Thanks again.

Rick

barry12345 · #4 01-04-2013, 10:28 AM

Unknown length of overheating it is hard to say how much is impacted. If the head was still spewing coolant when you pulled over there is still a good chance you have not taken the temper out of the rings at least.

kerry · #5 01-04-2013, 10:42 AM

It would be unusual for a blown headgasket to throw coolant out the side of the engine. I'd look for a failed hose somewhere or maybe a failed block plug or block heater. I wouldn't plan on pulling the head until the exact source of the loss is determined.

BillGrissom · #6 01-04-2013, 11:41 AM

I agree with kerry. I haven't heard of a head gasket failure throwing coolant out. I guess it is possible from the pressure of the water pump. Try removing the fan belts so the water pump doesn't spin. If pistons are throwing the water out, you want to at least get the water out of the cylinders and coat with oil so the rings don't rust to the liners before you can work on it. I also expect something in the water jacket (plugs, block heater) or hoses. The fact that the engine stalled is worrisome. Was it real hot then?

vstech · #7 01-04-2013, 11:56 AM

yesterday, my brother's honda blew steam and when he popped the hood, the radiator plastic tank had exploded... literally sent plastic chunks shooting across the motor.
I'm guessing the cap failed closed, and too much pressure built up. or maybe the tank was just junk and it spewed...
either way, fill it back up with coolant, and see where it's leaking... maybe it's ok!

Rolson · #8 01-04-2013, 11:24 PM

Thanks to all of you who responded.

I picked up some MMO today and tomorrow I will make time to pull the injectors, push any coolant out if there is any, and lube the cylinders for now.

It was the hottest engine I have ever seen when I pulled over and popped the hood as to the question about that. How long without coolant? Not sure, but maybe 10-15 minutes.

I looked over every hose, water pump, freeze plug, and the block heater and find nothing wrong. Unfortunately, I did not have anyone to turn the engine over so I could watch what was happening when I refilled it with coolant and only found the sprayed mess all over after I got out of the cab. I am assuming it's the head gasket and compression that had the power to spray it all over, including right out between the frame and fender liner above the passenger side tire. It covered the tire, the ground, and the vehicle sitting next to it from the pressure.

The only thing I know of that would have that much pressure just from cranking it over would be compression. I don't think the water pump would be capable of that much power. I could be wrong.

Soon I will have some time to get more serious about this and will have a helper turn it over so I can watch what happens when it is cranked and either confirm or deny my assumptions.

Thanks again everybody. Will report back with my findings soon I hope. I miss driving my truck.

Rick

Rolson · #9 03-11-2013, 02:17 PM

Recently removed the head, removed all the coolant from the cylinders, and have everything soaked down with MMO.

After scraping the underside of the head down with a razor blade, and wiping it down repeatedly with brakekleen, I thought everything was good. I talked with Roy and decided to get a new head gasket and put it all back together.

Then in another thread about a blown head gasket I learned that the cracks can be very minute and hard to see, and that gentleman used a scotchbrite type of wheel on his Dremel to polish the head and found some very fine cracks.

I went to the hardware store and bought some of those for my Dremel. Polished the area around the valves, and pre-chambers and much to my surprise I found 2 cracks on cylinder 3.

Now I'm trying to locate a good head for my block. Locally,(within an hour drive) I have located 2 of them at recyclers. One for $200, and the other for $350. Both sellers guaranty them to be free from cracks. Neither one can verify how many miles are on the engine they come from.

Not sure why one is almost double the price of the other.

When I get my hands on one of them, are there any other things I should have done, other than check for cracks myself, and check for flatness?

I have already ordered the valve guides and seals before I found the cracks on my head. Should I have them replaced now on the new head, just as a precaution?

Thanks for anyone to take the time to give their 2 cents.

Rick

whunter · #10 03-11-2013, 04:22 PM

Cracked OM617 cylinder head, please note the rough/pebbled (cavitation eroded) metal surface.
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#

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Volker · #11 03-11-2013, 06:12 PM

Would those cracks be considered "important" or could you still drive on it?

whunter · #12 03-11-2013, 07:02 PM

Quote:

Originally Posted by Volker

Would those cracks be considered "important" or could you still drive on it?

For a while, as it destroys your engine.

http://www.peachparts.com/shopforum/diesel-discussion/285883-om617-head-gasket-failure-pictures.html

http://www.peachparts.com/shopforum/diesel-discussion/325016-1980-240d-cracked-cylinder-head-cavitation-damage.html

http://www.peachparts.com/shopforum/general-information/272132-cavitation.html

http://www.peachparts.com/shopforum/diesel-discussion/155113-leaky-head-gasket.html#post1184752

1985 300TD head gasket repair
http://www.peachparts.com/shopforum/diesel-discussion/325433-1985-300td-head-gasket-repair.html

http://www.peachparts.com/shopforum/diesel-discussion/306995-om617-intake-exhaust-valve-guide-id-specification.html

http://www.peachparts.com/shopforum/diesel-discussion/272804-need-definitive-om617-compression-test-procedure.html

http://www.peachparts.com/shopforum/general-information/239902-home-made-special-tools-where-members-can-share-how-they-made-special-tools.html

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Rolson · #13 03-16-2013, 10:08 AM

I found a head at a salvage yard/recycler about an hour and 20 minutes away.

Overall condition of the head appears to be nicer than mine, and included cam, injectors, etc. I looked it over but was focused on the underside of near the valves, and did not recognize anything to be alarmed about so I made the purchase and brought it home. I was kind of in a rush to get back home with it as I had to be to work in less than 2 hours.

Yesterday when I was cleaning the gasket material off the face I noticed that the large coolant passages near the outside of the head between cylinder 3 & 4, and the one between 4 & 5 were plugged with an orangish, hard scale.

I started poking at it and broke it free, then decided to look very closely at the area around the valves on cylinder 4.

I began cleaning with a wire brush on my Dremel, and found a little more pitting on this cylinder versus the others, so I removed the valves from that cylinder and found rust on the intake valve stem, up in the port,and the seat is pitted, and wet with what looks like coolant.

Next I wire wheeled around the valve on the face and I think I found a micro crack in about the 2:00 position, but I'm more concerned about the rust up in the port, and on the valve.

I called the recycler, and he said to go ahead and bring it back as he wants me to be happy with it and would refund my money.

A few minutes later he calls me back and says he had just received a call from a guy in GR that owns a 10 bay service shop that only does German cars looking for a part for a client. While he had him on the line he asked if these old Mercedes diesel heads were known for cracks in the heads.

Supposedly, the shop owner told him that every one that came in his shop had small cracks. It was just the way it is with these old MB heads. He said I would probably never find a head without some small cracks in it.

They weld the cast and in 20K miles they would come back cracked in the same place, through the welds.

The recycler even offered me the guy's name and number to talk to him myself.

I told him that I wasn't as concerned about the micro-crack I could see as I was about the scale completely plugging the coolant passage around #4, and the rust up in the intake port on that cylinder and the crack that I couldn't see. If I had recognized the scale in those ports while I was there I would have left it and not purchased it in the first place.

He accepted that and said to go ahead and bring it back.

BTW, I just wanted to mention that there was no evidence of scale in any other port on that head. None. Very clean in all respects.

Am I being too critical and cautious, or am I right in assuming there is a serious issue up in the intake port that can't be seen with the naked eye?

Will post the pics of this later, as I need to get this back to them by noon today. Gotta go.

Thanks.

Rick

BillGrissom · #14 03-16-2013, 10:32 AM

Magnaflux is the typical way to find cracks. Most engine shops can do that cheap. The parts look simple - iron filings and a strong magnet, but I have never done or looked into buying. I think that cracks around the valve seat are the biggest concern. They are probably most common because that is the area of greatest temperature gradients.

Some heads are known for cracking. In M-B diesels, I have read that the 6 cyl heads almost all crack eventually. In Mopar world (where I hang out), the 80-90's Magnum small block V-8 heads often crack between the intake and exhaust valves because the factory induction hardened the castings around the seats rather than install hardened valve seats. Otherwise, people like those heads.

Small cracks in a head are common and I think the usual fix is to drill and plug at the ends to stop the crack from spreading, but otherwise leave it as is. However, I don't think that works for cracks around the valve seats. In gas engines, I think a machine shop could install hardened seats. Years ago, I had that done for my big-block Mopar for <$10 ea, but don't know about M-B diesels.

whunter · #15 03-16-2013, 03:50 PM

Quote:

Originally Posted by Rolson

I found a head at a salvage yard/recycler about an hour and 20 minutes away.

Overall condition of the head appears to be nicer than mine, and included cam, injectors, etc. I looked it over but was focused on the underside of near the valves, and did not recognize anything to be alarmed about so I made the purchase and brought it home. I was kind of in a rush to get back home with it as I had to be to work in less than 2 hours.

Yesterday when I was cleaning the gasket material off the face I noticed that the large coolant passages near the outside of the head between cylinder 3 & 4, and the one between 4 & 5 were plugged with an orangish, hard scale.

I started poking at it and broke it free, then decided to look very closely at the area around the valves on cylinder 4.

I began cleaning with a wire brush on my Dremel, and found a little more pitting on this cylinder versus the others, so I removed the valves from that cylinder and found rust on the intake valve stem, up in the port,and the seat is pitted, and wet with what looks like coolant.

Next I wire wheeled around the valve on the face and I think I found a micro crack in about the 2:00 position, but I'm more concerned about the rust up in the port, and on the valve.

I called the recycler, and he said to go ahead and bring it back as he wants me to be happy with it and would refund my money.

A few minutes later he calls me back and says he had just received a call from a guy in GR that owns a 10 bay service shop that only does German cars looking for a part for a client. While he had him on the line he asked if these old Mercedes diesel heads were known for cracks in the heads.

Supposedly, the shop owner told him that every one that came in his shop had small cracks. It was just the way it is with these old MB heads. He said I would probably never find a head without some small cracks in it.

They weld the cast and in 20K miles they would come back cracked in the same place, through the welds.

The recycler even offered me the guy's name and number to talk to him myself.

I told him that I wasn't as concerned about the micro-crack I could see as I was about the scale completely plugging the coolant passage around #4, and the rust up in the intake port on that cylinder and the crack that I couldn't see. If I had recognized the scale in those ports while I was there I would have left it and not purchased it in the first place.

He accepted that and said to go ahead and bring it back.

BTW, I just wanted to mention that there was no evidence of scale in any other port on that head. None. Very clean in all respects.

Am I being too critical and cautious, or am I right in assuming there is a serious issue up in the intake port that can't be seen with the naked eye?

Will post the pics of this later, as I need to get this back to them by noon today. Gotta go.

Thanks.

Rick

You are correct, the other fellow is dis-informed (or trying to avoid warranty).

Here is an example of a perfect OM616 cylinder head = no cracks, pitting, or other damage.

http://www.peachparts.com/shopforum/3008344-post4.html

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