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W202 C180 1996
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34 Posts
Discussion Starter #41
Hi george,

Thanks for the thorough reply.

Actually, all this exhaust leak theories was maybe just nonsense...I see no leak today. So it was oil getting burnt after all, I guess.

I will drain the oil as you told me, and maybe I will test the cylinder pressure.

A thing I did when I had the gasket leak a couple of months ago, was try to bleed the system out of air, with a funnel attached to the expansion tank. The funnel had a couple of inches of coolant, and air bubbles were coming out of it all the time. When I stepped on the gas, the coolant was bubbling like crazy and was actually splashing everywhere. That's how I realised I had a blown gasket...it was not air bubbles but exhaust fumes. So maybe that would be a good initial test.

In any case, I don't think I did a sloppy job with the gasket. The initial signs are pretty good: Once the temperature reaches 80 degrees, it freezes there and never surpasses it. The heater works perfectly as well, so there is coolant circulation. Neither of these were happening before doing the job (temperature ~100 degrees and sometimes more, and the heater never worked).
 

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1995 C220
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2,800 Posts
Sounds like you are good. You may be a little paranoid, just like I was when I did my head gasket. Its a big diy job, and after I did mine, I noticed all kinds of little things that amounted to nothing. Never hurts to be thorough and check things out though, and a fresh oil change is always good.
 

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W202 C180 1996
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Discussion Starter #43
Hi guys,

So everything seems fine, apart from the fact that now the engine stalls when its one neutral/idle....

It won't start, unless I step on the gas, and then, if I have it on neutral or step on the clutch, even while moving, the engine stalls.

This had happened for the first time when I tried starting the car up for the first time after the head gasket job, but pressing on the gas fixed it. I thought it was low fuel pressure at the time...

It had happened once a couple of days ago as well, but the gas solution fixed it. But now it won't go away...

Any troubleshooting procedure I should follow?

Cheers!
 

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1996 C220 2007 ML320 CDI
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1,830 Posts
Did you reconnect the throttle body harness? Also, is the throttle body the original in the car? They have the same problem as the main harness with the biodegradable insulation, but the problem is hidden inside the outer insulation. If this is indeed the problem, there are lots of updated used harnesses on eBay for a decent price, you need one manufactured after 2006.
 

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W202 C180 1996
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Discussion Starter #45
I guess you mean that cable that comes out of the throttle body. Yes I connected it.

I removed the air cleaner pipe this morning and thoroughly cleaned the inside of the throttle body, after reading this: >LINK<

I also realised I had forgotten to tighten the inner hose clamp like a complete idiot...(see pic) So maybe the problem was there.

a.jpg

After this I did ~100km on the highway, stopped to the side about 4 times for a few minutes and started the engine again, just to see if I can reproduce the problem (as the engine was stalling only when it was warm, or maybe I was just unlucky...?). Everything went fine.

The throttle body seems to be the original one. I mean, why would the cables inside go bad all of a sudden after the head gasket job? So maybe this thing I linked was right (also, that clip :grin)
 

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1996 C220 2007 ML320 CDI
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Well it's not that they went bad all of the sudden, they were already bad, but the insulation might have been holding on by a thread, and when you moved the wire around to remove the throttle body, you crumbled the insulation on the inside, exposing a new problem.
 

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W202 C180 1996
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Discussion Starter #47
So, just a small sitrep for you guys...

1)Engine-wise the car seems (somewhat) fine. No oil leak or coolant leak whatsoever. Oil pressure fine.
  • However, I think that the fuel consumption has been bumped up a bit.
  • Also, when the engine is on idle and the car stopped, the engine is not humming continuously but it is a bit intermittent. Idle RPM varies from 600-800, or 900-1000.
  • Plus, while driving, there seem to be some intermittent losses of power as well. I see no impact on the RPM, but you can feel the engine doing something like a small "hiccup" for half a second while stepping on the gas.
Any idea of what these are? Could those issues be connected to each other? Tried resetting the throttle body with reference to >LINK< , but those issues persist.

2)Some electrical malfunctions:
  • A sizzling sound is coming from the lights above the driver/passenger seats. Sometimes it is there, and sometimes not.
  • Both windows (electrical) won't roll down anymore...
Is there a short somewhere maybe...?
 

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1995 C220
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Double check your throttle and transmission cable are adjusted properly and hitting the microswitch on the throttle body properly. They may be fine, but if that microswitch isnt set properly it will cause some interesting issues with how it idles and drives. Given all the work that you have done, it is possible they need to be reset. Also, if you know someone with a scan tool that can read generic obd2, see if they can go in and reset the adaptive trim, so the car basically relearns the fuel trim numbers. It will do this on its own over time, but a reset will make it store some fail safe numbers to start with until it can relearn. This could be why you have some minor idle issues or hicups once in a while; it still has trim values from a motor with a failed head gasket still stored in the computer.
 

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1996 C220 2007 ML320 CDI
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For the brief loss power, I've had the exact same issue after I replaced the main harness, turned out there was a loose fuel injector plug (one of the pins wasn't staying in the plug). Exact same issue, a brief hiccup when stepping on the gas, but never severe enough to trigger a CE. I jammed the pin back into the plug, and filled it up with hot glue, and everything's been good for 2 years now. It might be something to look into. Also, the fuel injectors may be flowing incorrectly, they are quite old after all, cleaning them help you out. I should probably do the same, I'm sure the car would appreciate it.

As for the buzzing, might be more of a rattling clip issue rather than a short. I wouldn't lose too much sleep over that yet, wait for the headliner to start sagging before getting at it. For the windows, you might need to do a bit more diagnosing. You can roll the windows down with the key fob using the convenience feature. If they all roll down, you know it's an issue with the switches.

On the W202 with the IR flipkey, the convenience feature is activated as follows:

Point the flip key at the rear view mirror
unlock the doors
lock the doors, don't release the button right away, keep it pressed for a few seconds
unlock the doors, keep the button pressed
all the windows (and the sunroof) should open (you've got to keep pressing the button until they're all the way down, otherwise they'll stop wherever they are).

To close all windows, lock the doors, keep the button pressed until all the windows are up.

This also works using the driver's side key hole, just substitute pressing the button / keeping the button pressed for turning the key / keeping the key turned
 

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W202 C180 1996
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Discussion Starter #50
Hi all,

Solved the window issue (just a blown fuse), and found the source of the buzzing sound, so no worries.

Still however, the car is revving while on idle, and I think the fuel consumption is a bit higher than before. Also cleaned up the throttle body very thoroughly. No difference.

@georgebuhr
Where is the microswitch? Also, I have a manual, so no transmission cable I presume. How to check if the throttle cable is adjusted properly? Will get an obd2 reader soon I guess.

All in all, the car has been running for 600km now and no major issue has come up, apart from those small remaining issues...!
 

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1995 C220
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My mistake; with the manual transmission, you may not have the switch and for sure you wouldnt have the tranny cable. I would however look for a leak in the intake track somewhere past the throttle body that could cause your idle issue. Its either that or something is up with the idle air control. With it being a 96, you could have the rotted wiring on the throttle body which would affect the IAC.
 

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1995 C220
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Ok Andy, I finally had a second to check. I am using a snap On Solus Edge. Using the OBD 2 port(not the mercedes port under the hood), I went to OBD-II/Eobd(which is just the generic OBD II section if you using another tool), It gives me the option of OBD direct, or OBD II Health check. I choose OBD II health check. Then you can either do a Global OBD II code check, clear codes, Readiness monitors, or check MIL status. I went to Readyness Monitors.

At this point you have to be connected to the car to communicate with it, but once you get in that menu, there should be an option to reset the adaptive trims.
 

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W202 C180 1996
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Discussion Starter #57
Hi all,

So the idling problem was finally resolved. It was just a bent spark plug electrode. I was a bit clumsy while installing it and that was the result.

Anyway, now the car is 100% perfect. Thanks for your support and help throughout this endeavour...! I hope this thread is a good resource alongside the nice videos by andyP and patman. In retrospect, I don't think it was that difficult of a job...so if you are thinking about doing it yourself, go for it. It's good fun.

Cheers!
 

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Sorry I took a while to respond, had a very busy few days!

I used the Bentley service manual, but for all intents and purposes, as far as the Head Gasket goes, it's just as good a reference as the Haynes. It does sound like your HG is finished. The necessary parts for this rebuild will be: a new HG kit (it comes with a bunch of o-rings and other gaskets) and a head bolt kit. The head bolts are one-time use. You will also need camshaft sprocket bolts, at least one set (you'll be removing the exhaust cam sprocket). You might also need new cylinder head to engine block timing cover bolts if the ones present are a hex head. Service manual (and I double checked against WIS) makes you discard those and replace with Torx bolts. I would also recommend replacing all the coolant hoses and clamps while you're there.

Since your head has seen some abuse, I would send it out to a machine shop to have it surfaced, I would expect to see some slight warpage, mine was slightly warped, but otherwise everything else was fine. Didn't need to do a valve job because the cylinder head was tested for leaks and it was fine. The engine block is probably fine, Mercedes bottom-ends are hella strong. Just be sure to make clean the hell out of it before installing the new HG. If you want to be sure, you'd need to probe it with a straight-edge and some feeler gauges, but it's unlikely the block is warped. You won't need to replace the timing chain, by my educated guess, the timing chain is good for 500k km. I replaced my HG at 223k km and the chain was stretched by 5 degrees of crank rotation, out of an allowed 10 degrees before it goes out of spec.

No special tools are needed to pull the CH off, but if you have access to them, they do make the job easier. But otherwise everything can be done with easily obtainable tools.

I wouldn't mark the position of the camshaft just because as soon as the chain tensioner is released, your marks won't be aligned anymore, so you'll just sit there wondering what to do. Luckily, timing the engine is really easy, and it's probably covered in your manual. Just don't forget to reset the chain tensioner!

Trust the manual, follow it to the letter, and this is a VERY easy job.

My M111 HG video series on youtube isn't complete yet, I've got another video coming up soon. But as it is now, you've got enough information to remove the head and reinstall it, the rest is really just putting everything back together in the reverse order you put it in, so you're not missing much.
Hello patman1 i can't seem to find your videos on YouTube please post a link thank you.
 
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