So my new to me SDL with 183k miles runs like a champ but I think I am getting the dreaded head crack. I let it sit over night and the top hose is soft but start it up ice cold and it gets hard in about 7 seconds. I don't feel any pulsing or get any bubbles in the coolant tank but I think it's getting a bit of compression into the cooling system. It also runs rough for about 10 secs. after being started cold so I think it's getting water in a cylinder.

If I get into fixing it what year and model head should I get? I know there are a few. I have spoken to some that say welding can work if done by a good shop. What's the word on the street? Also I am in the LA area and would be interested in any recommendations of a place to do the head.

Thanks in advance...

In your case it might just be a head gasket. Of course get prepared for the worst but it is not always the head. If the gasket looks to be the problem do not hesitate to at least check the head for flatness as well as cracks. I would almost think with the hose getting pretty firm in seven seconds you should see some bubbling.

Why are you jumping to a very expensive conclusion? You've got one piece of data, and it's relatively weak.

Does the engine burn coolant?

Have you performed an oil analysis and determined that coolant is in the oil?

Get some additional data before you condemn it.

Runs rough for 10 seconds could be a lazy glow plug.

There's some discussion about Spanish replacement heads you might want to get in on. All conjecture since no one has contributed actual experience.

Basically you want any head with a higher casting number than 603 016 14 01, visible just above the #2 injector. The highest number I've seen is 22, which is what you get from an MB dealer. Of course you can fit another 14 head but you assume more risk. 17 and higher heads require some modification. You can have your prechambers reshaped to fit newer heads or get a $et of new prechamber$ and injector$. 14 heads were originally fitted to 3.0 blocks, 17 heads were originally fitted to 3.5 blocks.

I would stay away from reworked or repaired heads. I'm not confident that welding and surfacing can resolve issues with unsuitable materials. Also the savings is marginal in the overall scope the repair.

When your head is inspected, pay particular attention around the valve seats in the #4 and #5 cylinders. If your head checks out, it should be fine to reinstall. Check the valve guides and replace the valve seals with genuine MB parts. Aftermarket valve seals don't seem as well made although they look beefier.

Sixto
93 300SD

You need more data before you do anything, you don't know whats broke yet...if anything.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

dumb resource question to add to this issue.

Where does one get the oil analyzed?

Just for those of us who are clueless.

I know that this company will do analysis on motor oils, although in this case, the coolant needs analysis for the presence of oil. Possibly they can handle such an analysis, too.

www.blackstone-labs.com

They have an "Emulsified Oil" test for $55.00. I think this is what would be used to check for oil in the coolant.

I know several individuals that use this service on a regular basis. Very satisified with cost and results.

G'mornin',

I would not assume the worst until I had done some of the stuff mentioned above.....

I would remove the Coolant fill cap....start the car.....and note any differences in the level of coolant, bubbles, and smell.......you may be able to smell diesel exhaust coming from the coolant.....

There is a tool set that most good automotive shops should have, maybe a radiator shop....but this tool attaches to the radiator/coolant cap...there is a chemical solution that is put into the tool, and it changes color in presence of exhaust gasses....do your best to have one of these tests run before you begin considering removal of the head......

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

I thought I lost a headgasket... I forgot to tighten a coolant hose.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

As always, thanks for the fast response. There are no obvious bubbles in the coolant and I can't smell exhaust coming out of the rad cap. It does seem to use a very small amount of coolant and I have checked for leaks and found none. If it is burning coolant there is so little coming out the tailpipe it does not smell like it. I also had a very odd thing occur at start up yesterday where the motor seemed to stick and required a few bumps of the starter. I think that could be hydro lock but don't know. The oil looks totally fine but my only test is to look for milky color. I'll see if I can get to a coolant analyzer and report back.

What about stop leak products? I have heard they can fix small issues permantently.

I'll be very surprised if you see oil in the coolant. In my experience, that's only seen in marine engines that have pressurized oil coolers running on the coolant side, which are a rarity.
If you're getting coolant into a cylinder, at least some of it's getting past the rings into the crank base. Hot oil will boil off the water, but the bearing-destroying stuff remains. Oil analysis will find minute quantities of that, and also measure fuel dilution, which is not usually a big deal in engines without injection parts under the rocker covers.
Take the oil fill cap off the rocker cover, and wipe the underside of the cover with your finger. If it looks like oil, you're probably okay. If you come away with emulsified oil (looks like dirty brown mayonaise. Do NOT put on ham & cheese sandwich) then you've got coolant getting into the crank base.
As a VERY TEMPORARY fix, drain out the coolant and replace with plain water. Loosen the radiator cap so that you don't pressurize the system. Drive to the mechanic's shop

Personally, I don't like coolant additives like "Stop Leak" or "Bars Leaks"....as I understand it, they also tend to coat the internals of the entire cooling system....and thus reduce the heat transfer quality of both the engine's cooling passages, and the radiator......

Also of note......years ago, a friend of mine, graduate of the Republic of Colombia's Naval Academy, told me that his grandfather used old coffee grounds to slow/stop leaks in his farm vehicles cooling systems.....sounds good to me!!!!

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

You are absolutly right. The stopleaks or as they should be called waterglass solution do leave a glass like coating all over the place. Type of approch to use if absolutly nothing to loose. This coating is obvious if you take an engine apart that was treated. On an engine with marginal cooling capacity it might mean certain death. Also I am just suprised it works as well as it does more than occasionally. Too bad it does not just harden up at the crack or leak site only. In fact part of the illusion years ago with there advertising was that heat of combustion was required for setting. Probably not a complete lie but misleading for sure. It did imply that it set only where the crack was I believe. Most drug stores can order in waterglass if you wish at a much better price than auto stores. Gotta give the devil his due though. When it works it really seems to work. I know shady used car dealers that swore by it.