My 350SDL Head gasket replacement - Page 5 - PeachParts Mercedes-Benz Forum

vitop · #61 10-07-2012, 03:40 PM

I will also post pics of the head. The head actually looks good. I don't see any reason for oil to be squirting. What I do see is that the head gasket has some holes for coolant where the block has passages but the head does not. I see corrosion on the head in those areas. Are there different versions of head gasket that I need to be buying?

engatwork · #62 10-07-2012, 04:03 PM

Quote:

I see corrosion on the head in those areas.

I've seen this on a lot of al heads I've removed.

vitop · #63 10-07-2012, 04:08 PM

I imagine thats true, but with holes in the gasket with no place for the water to go in the head, wouldn't that continue to wear the head? And there is corrosion there, so it actually is an area that is lower than the head surface. So the gasket may not seal and you have water trying to push through on top of that. Doesn't sound like a good mix. Should the correct gasket have holes in those areas? seems like it should be closed off.

Quote:

Originally Posted by engatwork

I've seen this on a lot of al heads I've removed.

vitop · #64 10-07-2012, 06:19 PM

We got stuck with measuring the rise. We can't seem to figure out how to get a zero reference point on the block and then move the instrument over to the piston while keeping the zero reference. As soon as you move the gauge, the reference is lost. Somehow we are missing something easy, but we are not able to get good measurements.

sixto · #65 10-07-2012, 06:50 PM

Thinking out loud, clean the piston crown and block deck, set a level longitudinally over the piston, use feeler gauges to measure protrusion fore and aft.

Sixto
87 300D

vitop · #66 10-07-2012, 06:53 PM

Sixto - not exactly high tech, but yeah sounds like it would work. I'll try that

engatwork · #67 10-07-2012, 07:26 PM

Look at post #27 on this thread. Got some pics where I was measuring one.

350sdl

ChiefRider · #68 10-07-2012, 07:31 PM

Quote:

Originally Posted by vitop

We got stuck with measuring the rise. We can't seem to figure out how to get a zero reference point on the block and then move the instrument over to the piston while keeping the zero reference. As soon as you move the gauge, the reference is lost. Somehow we are missing something easy, but we are not able to get good measurements.

You don't need extreme precision for this, but you do need clean surfaces. One way to accomplish this measurement without dial indicators would be to use a dial caliper with a foot attachment.

With the foot attached and caliper zeroed, place the foot on the piston at TDC, and slide the tang of the caliper down to the block parting surface. You can get a satisfactory reading in this way.

vitop · #69 10-07-2012, 09:55 PM

Well, all we accomplished today was to take measurements. The head actually looks really good. We are going to test it for cracks, but it looks good.

Other than corrosion of the head gasket on some of the coolant ports, that looks ok too.

I am just not sure where the oil was shooting from. I can only think of two things at this time.

1) residual oil still in the cylinder from the turbo

2) bad valve seal.

Can the seal be replaced? I imagine you need a special spring compressor and didn't see one on ebay.

Also, if anyone can chime in on the question I asked a few posts back on the head gasket and the fact that it has open holes to allow coolant from the block to flow into a blocked part of the head.

It makes me think I have a wrong version of the head gasket.

None of the cylinders shows any ovalling at all. Cylinder #2 measures good in all respects - even with the rise. I do have a difference in front to back rise on cylinder #1 and have to see if it is within spec.

Otherwise, the only thing I saw is that the prechamber on #1 does not protrude as far into the cylinder as the rest of the prechambers. I wonder if that causes a difference in combustion. I need to get the prechamber tool to get the ring off if I am going to try to fix it. Not sure if I can just hammer it down more and tighten the ring. Any current space may be taken up by carbon at this point.

If I try to change the valve seals on #2, what sort of tool will I need?

And should I be looking for a head gasket that blocks the same holes that are blocked in my head?

vitop · #70 10-08-2012, 10:42 AM

I've got a call into Elring in Germany regarding the head gasket. I may have to purchase the gasket from the dealer. The ones supplied in the Elring kit are for the later heads. I am waiting for a definitive answer.

Can anyone help with the valve seal question on the head -- what tool can be used to replace them, or does everyone just take them into a machine shop?

sixto · #71 10-08-2012, 12:31 PM

The factory tools for valve spring work are expensive. The bridge and lever are separate items. You can fabricate your own tool like Jeremy did or modify a compressor that works on watercooled VW heads. Use a sheet of plastic as a cylinder liner so the compressor doesn't scratch the lifter contact surface. One reason to farm out the job is to have an expert evaluate the valve guides.

Factory tools -

Homemade VW tool (not necessarily dimensions for a 603) -

However you go, I suggest replacing all the valve stem seals, not just one valve or cylinder's worth. Experts say MB brand valve seals are the only way to go. There are special pliers to remove and install valve stem seals but these are less critical.

Strange things happen within the thickness of a head gasket so I wouldn't be surprised if that's all you need.

Sixto
87 300D

gsxr · #72 10-08-2012, 01:22 PM

I find it highly unlikely that you would get enough oil past the valve stem seals to cause oil to spray out during a compression test. Borderline impossible actually. If this were the case, those valves would be literally dripping with oil, while the other valves would not be. At any rate, it wouldn't hurt to replace all the seals, don't just change one or two.

IMO, you are chasing a red herring with the head gasket holes. That's just the way they are. The OE dealer gasket kits are made by Elring. I'd either buy OE or get Elring aftermarket gasket kits. Make sure they are for the 3.5L motor, not the 3.0 motor.

If y ou had oil squirting out of the #1 cylinder, I'd think that was the head gasket. I'm not aware of any pressurized oil passages that can only go into the #2 cylinder. I would not put that head back on without carefully measuring piston protrusion on all six cylinders AND checking with a bore gauge to measure ovality on all six as well. You won't be happy if you bolt it all up and still have the same problem.

vitop · #73 10-08-2012, 03:59 PM

gsxr - If the valve seal can not spray oil like that, then there really are only two more choices

1) residual oil from the turbo sitting after I had taken off the cross-over pipe

2) bad rings

I should have done a leak test, but didn't

I'm not crazy about the extra holes in the head. The original didn't have them and I think it will cause issues with coolant getting by especially since the head has been worn down in those areas.

I have two different head gasket numbers. I think Elring is now supplying only the later version that have more coolant openings. I can still get the earlier number from the dealer (at a higher price of course!).

I may order the gasket from the dealers and look at it when it comes in. If those passages are sealed, I think I'll pay the extra for the right gasket.

Of course, that solves my coolant problem, but not my oil problem. That is still a mystery.

Guess I can put the head gasket, head and cam back on it and do another compression check to see if I have squirting oil. The cylinders are now clean. Any oil would be coming up from the block for sure. It would eliminate any residual oil from the turbo, but it would cost me an expensive head gasket and a bunch of time if it didn't fix it.

I may also have the head tested to be sure it is ok. The guy I want to use is not there til Wed.

I think that would eliminate everything but the rings.

I don't anticipate doing this work often enough to even dream of coming close to covering a $630 tool to remove the valves. Someone ssaid they were able to remove them using the large OTC OHV valve spring remover and it only cost like $50. I may try that if I decide to do it myself

whunter · #74 10-08-2012, 04:41 PM

Quote:

Originally Posted by vitop

I'm not crazy about the extra holes in the head. The original didn't have them and I think it will cause issues with coolant getting by especially since the head has been worn down in those areas.

I have two different head gasket numbers. I think Elring is now supplying only the later version that have more coolant openings. I can still get the earlier number from the dealer (at a higher price of course!).

I may order the gasket from the dealers and look at it when it comes in. If those passages are sealed, I think I'll pay the extra for the right gasket.

The head gasket numbers are:

OLD DISCONTINUED NLA, new/old stock was recalled and destroyed when superseded.
MB# 6030161820

Current production
MB# 6030162620

.

whunter · #75 10-08-2012, 04:52 PM

Quote:

Originally Posted by gsxr

I find it highly unlikely that you would get enough oil past the valve stem seals to cause oil to spray out during a compression test. Borderline impossible actually. If this were the case, those valves would be literally dripping with oil, while the other valves would not be. At any rate, it wouldn't hurt to replace all the seals, don't just change one or two.

Sixto's photos above show the old MB tools. The newer/fancier tools are shown here and are $630/set from this vendor.

IMO, you are chasing a red herring with the head gasket holes. That's just the way they are. The OE dealer gasket kits are made by Elring. I'd either buy OE or get Elring aftermarket gasket kits. Make sure they are for the 3.5L motor, not the 3.0 motor.

If y ou had oil squirting out of the #1 cylinder, I'd think that was the head gasket. I'm not aware of any pressurized oil passages that can only go into the #2 cylinder. I would not put that head back on without carefully measuring piston protrusion on all six cylinders AND checking with a bore gauge to measure ovality on all six as well. You won't be happy if you bolt it all up and still have the same problem.

I disagree, it is not common, but possible.
If the oil supply passage is leaking into a cylinder.
An already saturated cylinder will force excess oil out every possible location.
It would also indicate a very poor seal between valve and seat, and sloppy-bad valve guides.
I have seen this before on the OM167:
* The valve guides had .085 MM slop.
* Valve guide maximum inner diameter is 10.025 MM.
* Actual measurement of the exhaust valve guides where 10.11 MM +.

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