Mercedes-Benz Forum banner

1 - 20 of 30 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
I have a 603, rev 14 head that I just removed. I'd had air in the coolant. Found traces of coolant in the #6 cylinder. I haven't measured the flatness of the head or the block to determine if warpage was the cause of the head gasket failure. The head bolts had more variance in tightness on removal than I would have liked. Cylinders 3 & 4 have cracks on the combustion chamber surface between the valve seat recesses. On one, the crack is about 1/2 way across the narrow part, and on the other it's all the way across and call it 1mm(max) wide. On a 1.6L VW IDI diesel I wouldn't do anything(Have over 200k on one since I found the cracks which were 2-3 wider at the time(was replacing head gasket) - engine now has 350+k mi with no further work). At what point do these cracks cause issue on this head via valve seat or coolant leakage? Also, are the head bolts TTY(Tighten to Yield) which means smart people only use them once, and does the head gasket come in different thicknesses(proper thickness determined by piston protrusion out of the block)?

Thanks.
 

·
Cruise Control
'87 300TD/'90 300D/'94 Quattro/'89 Vanagon TDI/'01 EV Weekender VR6
Joined
·
52,233 Posts
I cut my diesel teeth on VW diesels. They are notorious for large cracks between the valve seats, yet very few actually leak coolant or combustion gases. These 603 heads tend to acquire micro-fissures which allow combustion gases into the coolant, but not typically the other way around. I'm willing to bet your headgasket allowed the coolant into the cylinder and not the head itself. As far as I know, no one has been able to successfully weld up the cracks to eliminate the gas migration issues. The preferred solution is to buy a new #22 head, but there are also quite a few used #16 and up heads that should be superior to the old designs out there on the market.
 

·
Registered
money pits of various forms
Joined
·
5,885 Posts
They are stretch bolts, replace them. Head gasket no, prechamber sealing rings yes.

I will be replacing my 603 HG with a 606 HG (drill for the hole that doesnt match up). Recommendation is to cover both sides in copper RVT spray.
 

·
Registered
E320/E250 Bluetec Ford F350 6.7l
Joined
·
36,722 Posts

·
Cruise Control
'87 300TD/'90 300D/'94 Quattro/'89 Vanagon TDI/'01 EV Weekender VR6
Joined
·
52,233 Posts
So, technically they're not really "stretch" bolts, like VW/Audi use on their heads, but they do have a variance spec. I've successfully re-used them, since I've never found one to be out of spec.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #7
That would mean they're not TTY(or stretch) bolts - you don't tighten them into plastic zone, but stay in the elastic zone. Eventually under load everything elongates permantly a bit.

I suppose I should clarify that my head is off of a 603.96 engine(as found in an 87 300td). Not that it really matters for our discussion here.

I have the(I believe to be official) manual on CD for this vehicle, but it leaves much to be desired. I think whoever scanned it in used too low of a resolution as for example you can't read the bolt numbers for the tightening sequence(I had used common practice of working from the outside in evenly to remove the head). Another example is that it specifically mentions head bolt lengths for a 111, 602, 604, 605, and 606 but nothing for a 603 despite just giving me the tightning sequence for a 603(assuming you can decipher the numbers). Then Kajtek posts the link with much better instructions, now the question is where do I get a manual with that clarity for my car? I could live with cryptic instructions as long as the information is there and readable.
 

·
Cruise Control
'87 300TD/'90 300D/'94 Quattro/'89 Vanagon TDI/'01 EV Weekender VR6
Joined
·
52,233 Posts
The 602 and 603 are virtually identical, so the bolt specs should be the same. I believe there are two or possibly three bolt lengths with corresponding specs for each size. The DIY sticky at the top of the main 124 page has a link to an indexed factory service manual, which is about the best you're going to find. It has the torque specs/sequence for the 603.96. Also, most head gasket sets come with specs/sequence instructions included.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #9
Well, my 24" machinists straight edge showed up today, so I could measure the flatness of the head. After a quick cleaning, the head measures out okay along its length where the head bolts go, but out of tolerance by a couple of hundreths of a mm down the middle of the combustion chambers(where of course the carbon deposits/gasket rings are). I also have determined that the head has been milled before. At this point, I'm thinking properly clean the mating surfaces & bolt(all the bolts measure out ok) it all up and start looking for a 17-22 head. A quick look around has a couple of 14's available.

Would I be correct in thinking that a 22 head is what's on a 3.5L (Rodbender) 603?
 

·
Banned
1991 560sl / 1987 300TDT / 1995 E300D / 1994 S350D / 1993 300SD /Cummins Diesel PU /2 airplanes
Joined
·
861 Posts
Well, my 24" machinists straight edge showed up today, so I could measure the flatness of the head. After a quick cleaning, the head measures out okay along its length where the head bolts go, but out of tolerance by a couple of hundreths of a mm down the middle of the combustion chambers(where of course the carbon deposits/gasket rings are). I also have determined that the head has been milled before. At this point, I'm thinking properly clean the mating surfaces & bolt(all the bolts measure out ok) it all up and start looking for a 17-22 head. A quick look around has a couple of 14's available.

Would I be correct in thinking that a 22 head is what's on a 3.5L (Rodbender) 603?
A good machine shop can mill the head in 0.01mm passes. If you're not going to have that done then you are rolling the dice, which I have done. Sometimes you win, sometimes you do it over. I would use at least three good coats of CopperCoat spray (better uniformity) on each side of the head gasket, follow directions.

Good luck
 

·
Registered
Joined
·
17 Posts
Discussion Starter #11
Yeah, I know I'll be rolling the dice. The head is near min. thickness and between the small cracks in the head and the warpage I don't think spending the money on this head would be worth it.

While I'm at it, I'll be replacing the cooling system hoses. I think I've found all of them: upper & lower radiator, thermostat housing to expansion tank vent line, expansion tank connector hose, two on the hot side of the heater core, and 3 on the heater core return(to/from heater core maybe opposite of what I stated). Only the vent line is for sure not molded, and maybe one of the heater core lines. Anyway, do I have my count right?
 

·
Registered
300sdl '87
Joined
·
1 Posts
Does anybody know what head gasket you are supposed to use if you use a #22 head from a 350sdl on a 300sdl block (#14)? I notice that there are extra holes on the #22 head but am not sure what the deal is.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #13
As I understand it, either will work but if you use the 350 gasket you need to modify one of the oil holes. The 350 gasket is supposed to seal the cylinders better. Hopefully one of the experts will come along and clarify this for you.


Update on my project: Got all of my new parts, and got the old ones nice and clean(engine was an oil/grease special). Got the head back on and torqued down. Nearly had a heart attack when the allen insert(on my allen socket) fell down the chain hole as I was tightening those two little bolts on the front. Fished it out through the drain hole of the oil pan.

Now for a follow on question: I know the cam followers/hydraulic adjusters are supposed to go back where they came from, but the box I put them in got jostled, and I'm not sure they're all properly lined up. Two of the cylinders that I thought didn't get messed up have lifters with the same numbers on them in opposite holes(intake/exhaust). These are Mercedes parts. Here are the numbers: WX 6010500325 INA F-4615 and WXY 6010500325 INA F-4615. The WX and WXY are the only differences. So which should go where as I'm thinking that one is intake and the other is exhaust(which usualy have different gap values)?
 

·
Registered
1982 416 Doka
Joined
·
335 Posts
Hi
I am strongly suspecting a bad #14 head.
uses coolant yet passes a pressure test and has begun to overheat..

I was offered a 3.5 head (at salvage yard) for 850? good deal??
and was not sure it would bolt on..? If so, what else would i need from the donor car? injectors/ lines ect?
Thanks
Doc
 

·
Cruise Control
'87 300TD/'90 300D/'94 Quattro/'89 Vanagon TDI/'01 EV Weekender VR6
Joined
·
52,233 Posts
Depending on the mileage and measurable wear, that might be a decent deal. I think you'll want the injectors, and the lines would be nice, but not entirely necessary. It will bolt directly onto the block with no issues whatsoever.
 

·
Premium Member
Joined
·
1,241 Posts
there is another issue there , if the head got too hot at some spots , particulary bettween cylinders [ narrow ] the heat treated aluminum looses its temper at those spots .mb call it a flame effect .you are suppose to do a hardness test at those spots , and if head got soft there it should be replaced .if you dont , the gasket will fail again soon at same place .usually within one year . seen it twice , i dont touch a overheated 603 or newer anymore .replace the head bolts .
 

·
Registered
Joined
·
17 Posts
Discussion Starter #17
Well, I rolled the dice & lost. Got it to hold for a while. Not as long as I would like obviously. Even tried some of that head gasket sealer stuff(Magnesium silicate/liquid glass stuff) that worked for about a week. I said what the hell when it started leaking again.

Found a rebuilt 20 head that's on it way. Any advice on which head gasket to use - the one for the 3l or the 3.5l 603?

Also anybody got an idea where I can get the expanded metal piece that goes one the exhaust manifold between the front piece(#1&2 and the rest of the manifold)? Mine's cracked.
 

·
Registered
money pits of various forms
Joined
·
5,885 Posts
I used the 606 HG and drilled out the necessary holes one per cylinder for oil or water and 1 big one for oil. It is MLS the others are composites. Dont forget to put a piece of wood underneath when drilling!

I bought my accordian piece from rust @ buy mb parts.biz but any dealer or classic parts can get it. The cost is stupid, 40 bux or so.
 
1 - 20 of 30 Posts
Top