Head gasket... when to replace... - PeachParts Mercedes-Benz Forum

87tdwagen · #1 11-26-2013, 01:55 PM

So like many, I have been living for years with the common occurance of my OM603 head gasket leaking oil by the #1 cylinder to front cover union. Outside of it leaving an oily mess wherever I park, the oil loss is minor in that I do not have to top it off between 5k mile oil changes.

That aside, my engine still has the #14 head onl it, and while I'm interested in resolving the leak, I'm wondering if I will be risking more damage (possibly to the head) for wanting to change the gasket. That and I'm not looking forward to the huge amount of work involved.

From your collective experience, do these oil leaks get progressivly worse? Will I have other bigger problems if I let this one slide further? Any advise is welcomed.

No cooling system loss, nor oil in the coolant or visa versa, so thge oil and coolant are not mixing currently.

TIA

sixto · #2 11-26-2013, 03:29 PM

About the final stage is sufficient oil leak into the #1 cylinder to flood it. Exhaust smoke and rough running will overwhelm you before the cylinder hydrolocks (this isn't a guaranty!). There's a school of thought that suggests r&r'ing a #14 head can accelerate cracks that would have taken far longer to breach the cooling system if left alone. Thus IMO your concern is founded - find a replacement head for when you replace the gasket or live with the leak.

Sixto
87 300D

jt20 · #3 11-26-2013, 03:31 PM

The gasket is leaking. It has surpassed its effective lifecycle, in this case.

The head now has more freedom to move in various directions now (degrees of freedom) - this leads to warpage - warpage can lead to cracking.

Its not so much about the headgasket itself since you pay close enough attention to symptoms and will have a good idea of when "the time is right".

however, that may be "too late" as repeated stresses on the head in unintended ways will go unnoticed and will be more costly.

Vapors may go unnoticed, as well, and seize the head bolts in the block.

engatwork · #4 11-26-2013, 03:38 PM

What mileage are you at?

87tdwagen · #5 11-26-2013, 09:47 PM

Thanks guys

Time to look for a new head and other related "while I'm at-it" parts and get ready for a PIA job ahead. Hoping it's just the HG, the later heads are not easy to come buy at a "reasonable" price.

As to mileage I'm at 278k which one would expect a reasonable service life for a HG. Other than that she has had no operational issues, closer inspection of the head will tell the final story

Any tips, tricks or advice to share?

87tdwagen · #6 11-27-2013, 07:06 PM

Amazingly I did manage to source today a used (supposedly pressure tested and resurfaced) #17 head, prechambers and fuel lines for a super price. I'll assess the quality of that purchase when I see it in-hand. Hopefully it is a keeper as it will offer me some flexibility as to when I tackle the job.

Now given that I may soon have a sound replacement head on hand, what are your thoughts of replacement if there is nothing wrong with the #14 head? Do I upgrade it anyway with the #17 no questions asked? Or would it be prudent to return the #14 with a new HG back to where it has been happily mated for 26 years? Kinda old school, but I like keeping things original unless there is a big advantage in performing the upgrade. All this is hypothetical as I wont know until I get the original head off and have it tested.

Are there any other conversion specific parts needed to upgrade the head to a #17? I know of:
Slanted Prechambers
Fuel lines

How about Injectors and glow plugs?

TIA

ichris93 · #7 11-28-2013, 09:42 AM

Quote:

Originally Posted by 87tdwagen

Amazingly I did manage to source today a used (supposedly pressure tested and resurfaced) #17 head, prechambers and fuel lines for a super price. I'll assess the quality of that purchase when I see it in-hand. Hopefully it is a keeper as it will offer me some flexibility as to when I tackle the job.

Now given that I may soon have a sound replacement head on hand, what are your thoughts of replacement if there is nothing wrong with the #14 head? Do I upgrade it anyway with the #17 no questions asked? Or would it be prudent to return the #14 with a new HG back to where it has been happily mated for 26 years? Kinda old school, but I like keeping things original unless there is a big advantage in performing the upgrade. All this is hypothetical as I wont know until I get the original head off and have it tested.

Are there any other conversion specific parts needed to upgrade the head to a #17? I know of:
Slanted Prechambers
Fuel lines

How about Injectors and glow plugs?

TIA

I don't know anything about the different heads. But I would think if the #17 has been refurbished with new seats and guides I think that would be the way to go. That alone has to be better than a head with over 200k on it.

vstech · #8 11-28-2013, 10:25 AM

what price did you find the head for? how much has been done to the head besides resurfacing? Valves redone? Guides? Seals? lifters? cam? 300K can wear into the caps on the lifters, so be sure and inspect them or just replace while they are out. I think you can put your injectors in the slanted heads. My #22 head has slotted PC locks, not the splined ones...

sixto · #9 11-28-2013, 01:14 PM

You'll have to check what prechambers are on the #17 head. They might be vertical prechambers made to fit in which case you can reuse the injectors from the #14 head. Otherwise you need a set of inclined injectors. Glow plugs are also matched to prechambers. IIRC it's Bosch 80007 for vertical and 80031 for inclined.

I said this already but I'll say it again - retorquing a #14 head might cause cracks. If you have a later casting in hand, do yourself the favor.

Sixto
87 300D

87tdwagen · #10 11-29-2013, 03:02 PM

vstech and sixto,
thanks for the info. I'll have to assess the true overall condition of the head when I get it. I paid $550 for the head, with pre chambers and fuel lines. The head #17 is bare, tanked, pressure tested and re surfaced but does not include any valves, guides, etc. So i will have to transfer this over from my #14 when I swap them out. It will still get a head done at the machine shop and probably add all new lifters as well while at it.

Will need to assess the pre-chambers when they come in, but from what I've been told they are the slanted type which means that I'll also have to get new injectors and glow plugs.

I have bozio nozzles in my current injectors, would thos be usable in the later style injectors?

Thanks

Stretch · #11 11-30-2013, 01:22 PM

You might want to consider the "merits" of something like Hylomar spray on gasket dressing.

^^^^ yes yes yes that's a picture of a sump gasket on a M102 but the Hylomar spray on gunk is meant to be good for head gaskets too.

I do encourage you to read about and make up your own mind on this as it quite possibly falls into the snake oil category!

Some people swear by it (or hair spray!) on their gaskets whilst others think less of it.

I'm giving it a go on my M102 refurbishment I'm messing about with at the moment - the M102 also suffers from corrosion related head / block trouble

87tdwagen · #12 12-05-2013, 01:38 PM

Thanks Stretch,
Will give it a shot. On Thanksgiving day, while crossing alligator alley in So. FL, my serpentine belt exploded. Funny enough, I heard nothing, felt nothing, just noticed my "Bat" light came on and then my temp started climbing. Pulled over to see what was wrong and didn't even notice the fact that I was missing a belt, it desintigrated completely, found a few pieces, but surprised me as the belt is only 3 years old and has less than 15k miles on it.

Luckily I had an old spare in the trunk and an hour and lots of oily mess later I was back on the road. Had to fix some wiring that the belt took out, but nothing to really worry about. Just surprised that my "new" belt would fail this soon. All of the pullys are straight and the tensioner is fine as well. Got a new belt on her last night and put trusty spare back in the trunk.

Should be picking up my "new to me" #17 head and prechambers and will give them a thorough looking over, then determine if this oil leak is worth the effort of the swap over at this time.

Without sounding too crazy, has anyone who has the #1 cyl oil leak from the HG, ever successfully plug the leak without swaping out the head gasket? Any attempts at sealing the area with JB Weld or the likes?

Not too enthused about going through all the work for what is just an oil leak right now, but I'm also growing tired of the constant leaking on my driveway.

Thanks

sixto · #13 12-05-2013, 08:46 PM

The external leak is half the issue. Oil leaking into #1 can't be fixed with JB Weld.

Sixto
87 300D

87tdwagen · #14 12-06-2013, 09:48 PM

So the head came in, and this is what I have. No obvious cracks and fairly clean, a little pitting on the head, but looks minor to me and should be within the sealing limits of the head gasket. It's been resurfaced for sure, but can't tell how much was taken off, looking at the combustion casting void, it does not look like much was removed, a "light" decking.

Does anyone know what the limits of decking are, or how I can measure where it's at now? Don't know if I will need to get a thicker head gasket or if I can stick with a standard thickness.

Posting some pics, Please tell me what you think based on what you see or areas that I need to pay particular attention to.

Oh, and there is an example of the slanted prechamber and spline lock ring. I also have all of the cam bearing caps. Hope I got a good deal...

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Wadda ya think?

Stretch · #15 12-07-2013, 02:32 AM

It looks nice - except for the corrosion dents / damage. The water(?) hole between #5 and #6 doesn't look to great => zoom in for a closer look?