“That cold-start clack in your nephew’s Civic: does it disappear after a few hundred yards too?”
Yes. The clack would also disappear during the summer and return when cooler weather returned. Most of that quarter inch drop could have taken place right after radiator work and be due to air working its way out. We’ll see what the next 6 weeks does to the level.
You sound a lot more optimistic than I am about that small coolant puddle.
Tomorrow I’ll try to wipe it off thoroughly, it’s not easy to reach. And then I’ll check again later.
What I meant with my question about your nephew’s Civic was:
When the cold-start clack appears – no matter which season – does it disappear after a short distance, like in my case after 150 – 200 yards?
Yes it does disappear after 150- 200 yards. It was the same scenario you described: cold start and then accelerate up the driveway going up a moderate rise.
Then I think your nephew can also realistically hope that it’s just a lifter.
But I must confess, that - other than on high performance 2-stroke engines - I don’t have any experience with piston slapping (fortunately).
@H.D.
In regards to that coolant leak . . . there’s no way it’s that coolant pipe that’s at the rear of the head?
"Then I think your nephew can also realistically hope that it’s just a lifter. "
Hondas use screw-adjusted rockers; not a hydraulic lifter in sight, and his were in spec.
@ db4690
“… there’s no way it’s that coolant pipe that’s at the rear of the head? …”
Thank you for your favorable question db4690! You have very detailed memory of the M103 engine.
The coolant puddle is below that pipe, however the cylinder head surface around the pipe seems to be dry. The hose which is connected to the pipe is dry too.
The first 2 pictures shoe the coolant leak area.
In regards of these oil stains along the underside of the intake manifold: they may stem from spilling engine oil during refilling (sometimes in a hurry I don’t use a funnel). But you certainly know how to interpret them better than me.
The second 2 pictures show the oil leak area at the front right corner of the engine.
This morning I took another picture of the coolant leak area.
Animated by db4690’s last posting I wanted to know in detail what the cylinder head surface below the coolant pipe looks like.
I had to use a very small camera due to space limitation and hold it next to the oil filter (the blue thing on the left of the picture). That way I could take the picture from the bottom up.
The coolant hose is partly hidden by that cable and it’s shadow in the foreground.
On the cylinder head surface below the hose there are some traces of reddish stuff (and some dark traces which seem to stem from running liquid.
After I took the picture, I cleaned that wet spot on the block and drove about 10 miles.
After that everything was still dry.
I checked again an hour later: still dry (the coolant hose was still warm).
I checked again seven hours later: the wet spot was back !
Then I checked the surface of the cylinder head below the pipe with my finger: wet !
I made sure I didn’t touch the bottom edge of the head.
The end and the underside of the hose were dry.
So, at this point it looks like only this pipe, which db4690 mentions, is leaking.
Imagining that I would have taken off the head and later have found out, that the wet spot is still there due to that leaky pipe, makes me really appreciate db4690’s attention!
The pipe is tack-welded to a bracket which is flanged onto the side of the head.
I guess there’s an O-ring between the pipe and the head, right db4690?
HD, you have mentioned before the possibility that your timing chain could be stretched slightly. could it be possible that it is causing your idle shakiness, which then goes away when you put the stress of acceleration on it, causing the slack to transfer to only one side of the chain, while when idling the slack goes back and forth on either side of the sprocket, causing slight fluctuations in your timing?
for some reason I really am hoping you get this car perfect. perhaps I m living vicariously thru you?
DB?
@H.D.
Correct . . . there is an o-ring, which undoubtedly is flat as a board, so to speak
Be prepared . . . that bolt may get internally rounded by the time you have it out. Make sure you have a new one on hand
@wesw
Yes, I am also enjoying this thread. I hope that I’m able to help somebody, through this website.
I also appreciate that @H.D. is keeping us informed, every step of the way
me too, but I was wondering if my timing chain comment was totally stupid or not
No stupid comments, not that I’m aware of
Thanks guys! – for seeing me through this!
This idle issue is quite a project, isn’t it?
There are a number of German forums on the web dealing with this idle problem on the M102, M103 and M104 engine.
Some people say they solved it by fixing false air leaks, some by renewing things like the distributor, the injectors, the OVP relay, the air flow sensor (potentiometer), the EHA, and several other things.
One guy said, that he fixed it by renewing the heat sink paste between the ignition ECU and the surface it is mounted on.
Some people in these forums talk about expensive and unsuccessful attempts at Mercedes workshops to solve this problem.
But most of these discussions just stop at some point without a solution - at least without the announcement of a solution.
One mechanic at a Mercedes dealership who is still familiar with the W124 model - after test driving my car – said: “If it were my car, I wouldn’t mind this little shaking at idle so much. Don’t worry about it, this engine will probably shake for another 15 years.”
But for me, shaky idle has no place in a classy Mercedes coupe!
@ wesw
“…when you put the stress of acceleration on it, causing the slack to transfer to only one side of the chain …”
Besides idle the engine runs very smoothly not only during acceleration, but also during cruising at any rpm range.
Looking at the timing chain assembly (see picture), I think the slack is always on the side of the tensioner (12 + 13) which can certainly compensate for significant chain stretching. With the chain travelling clockwise it is rail-guided (3) on the tractive side over almost the whole distance between both sprockets. (just for guidance: (10) is the crankshaft and (9) is the oil pump)
However – even with a still completely compensated slack due to sufficient tensioning – the valves consequently open later with a stretched timing chain, because related to the crankshaft the camshaft backdrops a little.
That’s what I think has a worsening effect on idle quality.
@ db4690
“… Correct . . . there is an o-ring, which undoubtedly is flat as a board, so to speak …”
Another example, that the plastic and rubber parts of aging cars (no matter how tiny they are) are one of the biggest sources for trouble.
And thanks for getting me prepared for this (bad) bolt! As you can see on the picture, the bolt’s head is already partly corroded.
What do you think about the last picture in my posting from Tuesday – the one which shoes the area of the right front corner of the engine taken from below the exhaust manifold? I still guess that the oil probably comes from that seemingly damaged rubber seal of the upper front cover only, and not also from a damaged head gasket.
By the way, I wonder whether this is the original head gasket. What do you think?
a bit more to it than the chain on my '75 ford truck, which is the only timing chain I have observed
“…related to the crankshaft the camshaft backdrops a little.
That’s what I think has a worsening effect on idle quality.”
Looks like you have some slots on the cam sprocket if you want to advance the valve timing a little to test this theory.
@ insightful
Actually that drawing shoes the first sprocket design which Mercedes used on this engine until late 1985. After that (like on my engine) they changed the design in such a way that you have only 2 options regarding the camshaft timing.
For both options you have to take the sprocket off the camshaft.
To change the timing by 3° toward late you rotate it clockwise by about 140° or so and put it back onto the camshaft.
To change the timing by 3° toward early you flip the sprocket so that the front face goes to the back.
Only in these 2 optional positions the bolt holes align with the thread holes and a locating pin aligns with a locating hole.
Anyway, since I don’t know yet whether my timing chain is stretched at all or not, I want to wait until I have the valve cover off and I can see whether 2 marker pins ( 1 on the camshaft flange and 1 on the camshaft bearing cap align with each other when I turn the crankshaft into the ignition-TDC position of the first cylinder (there’s a mark on the crankshafts vibration damper).
I don’t know whether my timing chain – even if it is stretched a little - has anything to do with my idle problem.
I just regard timing chain stretch as a possible reason for bad idle quality.
Hey wesw! – I see you changed your picture!
Judging from the age of the picture and the age of the kindly looking elder lady in it, I guess it’s your grandmother, right?
my great grandmother, she passed at 98, some years ago. and you are quite perceptive. she was the kindest lady I ve had the privilege to know. her husband died in WW1. her grandfather served in our civil war. she worked at woolworths for 60 yrs, walking to work every day, until her late 80s and cooked sunday dinner until her early 90s. her food was sublime and I have never tasted its equal.
she lived long enough to see her great great grandson, my boy, sean
thankyou for asking