Last Sunday morning at 8am I headed off in my 190E-2.3 Sportline 5-speed. Just over 3 hours and 300km later I arrived at my brother's house. He had already drained the coolant (most of what was still draining was oil!). We then proceeded with removing everything necessary to get the cylinder head off.

I had not done an M102 before but figured it should be similar to doing the M103 only easier. Most of it was except for some awkward inlet manifold nuts and bolts. I prefer to leave the inlet mainifold with all the injection and wiring in place in the engine bay rather than lifting it all out with the head as various workshop manuals suggest (this has been the topic of discussion here previously regarding the M103). The pins retaining the timing chain guide rail proved very stubborn. Even with the correct slide hammer we persisted for probably an hour before we had them out. I have a black thumbnail and skinned finger to show for that part of the job.

After about 4 hours we finally had the head off. Everything looked clean and in good condition (as it should after only 90,000km and 11 years) except for the head gasket which was badly corroded around the coolant passages. This had been the case with the head gasket on our M103 when it suffered the same oil-in-coolant symptoms. This appears to be a common fault with these gaskets. The problem looks to be that no provision is made to prevent coolant from soaking into the gasket thus causing the steel layers to rust. I now change coolant annually (rather than every 3 years as our owner's manuals recommend) in an attempt to prevent this happening again.

With everything packed away and the head wrapped-up in the boot (sorry, trunk) of my car I was on my way home late that afternoon. Incidently, my 190E drove faultlessly, cruising at around 115km/h (2700rpm in 5th) and using just over 7.5 litres per 100km or about 37 miles per imperial gallon.

Checking the head reveals that it is flat to within less than 0.002" or 0.05mm which is well within spec. A leak test on all the valves shows that they are sealing perfectly. For this reason I am not sending the head to an machine shop. I have cleaned it and will fit new valve stem seals when I get the gaskets etc. I have also decided to replace the head bolts after reading an article about "torque to yield" head bolts. It is also unclear as to the stretch limit of the bolts. Every shop manual I have for the M102 quotes the bolts at 119mm new with a max stretch length of 122mm. The bolts we removed all measure less than 115mm. Does anyone know the length they should be for a 1.8 litre M102?

Assuming I have all the parts I need, next weekend I will again make the journey to put it all back together. I have asked my brother to have everything clean and ready to reassemble. I have also asked him to flush the radiator, expansion reservoir and heater to remove as much oil contamination as possible. We will replace all the hoses that are easy to access. For the first week after reassembly I would recommend that he gives several flushes of the cooling system with water before refilling with the correct coolant mix.

I will report back when I have more news.

__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.

For all the trouble these engines have on HG's-

Use only a current dealership sold headgasket. It's not worth doing again... if a dealer gasket leaks in 12 months, the repair is on MBUSA!!!


By the way "The head gasket leaked despite annual MB/distilled water coolant changes" - mercedes specifies normal drinking water. I think the buffering agents actually require some mineral content. Seen threads on it before.


Michael

__________________
Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

According to Frank King in the Star Magazina, MB permitted the use of drinking water but you can use distilled water if it's mixed with anti-freeze. It's then no longer distilled water.

The problem with *drinking water* is that it's generally tap water and you never know what's in it. I never permit tap water in my cars except that it's too late now because the dealer used it to flush out the cooling system when he replaced the head gasket in my car.

I've heard that distilled water can cause the head gasket problem or it could be caused by Redline Water Wetter or just a design flaw in the original head gasket. I think it's the latter.

Sorry I don't know Frank King very well=)

I was paraphrasing Stu Ritter whom is the technical chairman of the Star magazine. All MB requires is it's drinkable water. Stu is also a chemistry major from college.

It *IS* a know design weakness. M103/M104 headgaskets have been redesign many many times. Latest has a metal o-ring seal around the oil feed.
A bad gasket doesn't mean an abused engine in a M103. So milling, etc is not arbitrarly recommended. Yes, measure flatness but failure can be due to just age/use/bad design!


Michael

__________________
Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

Since my last post, I have purchased all the parts needed to complete the job. The most expensive item was the lower radiator hose! We decided to replace all the hoses due to oil contamination. I fitted the new valve stem seals and gave the head a thorough final clean before wrapping it in plastic.

The new head gasket appears similar to the old one except that the red (silicone, I think) seal that runs around the perimeter now also completely surrounds the oil feed hole (which it did not previously). This was not a metal ring as Michael (samiam4) suggests is the case with the M103 and 104 though.

I solved the mystery regarding the head bolts. The old ones were the type with the larger heads that do not use a washer and were therefore shorter than the specification in the manuals. The new ones with washers fitted (which I then also had to purchase) were about 1mm shorter than the old ones. The old ones had therefore stretched about 1mm and could have been re-used (based on 3mm stretch being allowed). At least we have no doubt with new ones fitted. Most of the stretch in the old ones had occured in the portion of thread that does not engage in the block.

On Saturday I again made the almost 600km round trip to my brother's. He had cleaned the top of the block and the holes for the head bolts. He had also flushed the radiator, heater and coolant reservoir. Everything went back together fairly easily (although the chain guide rail pins were very tight going back in too) and I torqued everything correctly. I lubricated the camshaft and rockers before reinstalling and reset the chain tensioner before refitting. I confirmed the correct valve timing and turned the engine over by hand to ensure all was well. Initially we filled the cooling system with water to ensure no oil contamination remained. My brother can flush it in a few days and fill with the correct MB coolant.

It was reassuring when operating the starter it burst into life. With no leaks and everything sounding fine a test drive confirmed that the job was a success. My brother paid me for all the parts and my petrol costs and gave me a very nice 1998 cabernet shiraz for my trouble ('98 was a good year for Aussie reds!).

__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.

Where did you buy the headgasket?

In the USA, it makes a big difference... I would only by one from Mercedes parts department to insure the latest style. In the USA, MB will replace it free if it leaks within a year *parts and labor* which is very attractive.


Michael

__________________
Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

Michael,

I purchased all genuine MB parts from my local dealership. For internal engine bits I am probably most comfortable with this. Obviously, with more time available I could have shopped around for some of the other bits such as hoses. The lower radiator hose was one of those bits that, had I seen the price first, I would not have purchased it. About $127 AUD was just crazy. As a comparison the head gasket was about $70 AUD, the head bolts (10 in total) under $9 AUD each and the washers for the head bolts a bit of a surprise at over $2 AUD each. To put this into perspective $1 AUD is about $0.76 USD at present.

Having said that I am more comfortable with genuine parts, several years ago when I did the same job on our M103 (300TE) I fitted a non genuine head gasket that is still fine. The shop that machined the head for me also supplied the VRS gasket set, hence the non genuine head gasket. That gasket looked to me to be less likely to suffer the problems the original did. I think from memory it had a metal ring around the oil feed hole.

Greg

__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.