I am deciding what I should do regarding a couple of issues with my recently purchased 1990 190E 2.3 Sportline 5-speed manual (mainly why I bought it). Prior to purchase I inspected the car and came to the conclusion that for its 211,000km it presented well. Body and interior (leather) perfect. Receipts for recent work including engine mounts, brakes, alternator and new battery and tyres. Sevice history a bit patchy but those that have been stamped have been either MB dealer or good independant shop. Engine oil clean and engine clean when looking in through oil filler. Oil pressure hot looks good at around 2 bar at idle. Price was good, especially for a model that is very rare in Australia.

Now for the questionable bits. There was a hint of oil in the coolant. Not much, but a hint. Previous owner claims head gasket was done some time back but no evidence to prove. If this were the case the coolant resevoir could have had some oil remaining from a previous head gasket failure. Coolant did not look very fresh so I flushed cooling system including heater and reservoir. Keeping an eye on it but no more oil in coolant since.

At cold startup lifters and timing chain are quiet. During warm up however, there is an intermittently noisy lifter that is fine once the engine is at normal temperature.

Engine starts and runs perfectly and pulls well from idle right up to redline. Not a trace of smoke and uses no oil or coolant. Fuel consumption is normal.

Should I:
1. Not worry about anything other than keeping an eye on it and continue to drive it and enjoy it (Which I am!).
2. Try a different oil in the hope it will silence the noisy lifter. Still has the oil that I purchased it with since it is not yet due for a change.
3. Replace the noisy lifter.
4. Re-torque the head bolts.
5. Pull the head off and get a full head job done.
6. Replace the timing chain and rails etc. It has a double row chain and no chain rattle on start up. I have no evidence that the chain has ever been done.

I would be comfortable doing any of this myself but obviously would prefer not to if it is unecessary. A few years back I did the head on our 300TE (M103 engine) when it started pumping oil into the coolant due to a corroded head gasket. The M102 is a similar four cylinder version of the M103 six. Many years ago I did the heads, chain and guides on the M116 in my 350SLC.

Opinions of those with experience with the M102 2.3 would be appreciated.

Thanks

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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.