Camshaft Hal Sensor and CEL

[Azeem]

Hi,
Last night my car didn't start on first attempt and I got the Check Engine Light in dash.
It didn't start on 2nd attempt and on 3rd attempt it started but the Engine Light stayed on till I reached home.
The car started on 1st attempt after that but Engine Light stayed on.
In the morning the car didn't have any starting issues and started on 1st attempt with the engine light stayed on.
I took the car to dealer ship after that, when the restarted the car the light went off.
Anyway, they hooked computer to check for CEL errors logged and found out 'camshaft hal sensor error' and 'crankshaft position sensor'.
There is no engine light and is running fine now. Dealer also said there's nothing to worry about and after scanning a couple of times and test drive no errors were logged.

I have couple of questions to forum members:
Which part should I order camshaft hal sensor or CPS? Could any one send me part numbers of OM 647 engine.
My car overheated couple of weeks ago, could it be due to overheating?
Thanks

 

[Tuercas viejas]

Azeem
Greetings yet again!
The cam sensor mounted on top of the valve cover is subject to heat effects if your engine has started to glow in the dark.
The sensor sets the injection timing and is synchronized with the crankshaft sensor to ensure smooth engine operation. On a scanner you can see the pair go synchronized when running.
I would be inclined to replace the sensor as it most likely has been compromised. I would be inclined to replace both including the crank sensor if the budget allows .
Beware the crank sensor can get corroded into the block port and you can break it easily.

Also pay particular attention to the socket as it can become loose on the sensor and give you the same problems.

Also the three #18 wires that connect it to the PCM can get corrupted and careful ohm outs and resistances need to be verified as in about 20% of my experiences with this problem & wiring is the issue when an engine has overheated.

On a broader issue be mindful of engine overheats its the killer of this engine. The accessory belt, the idler rollers and the tensioner are all very critical to keeping the engine cool.
Replace it all at 175,000 kms.
The engine thermostat should be open at 90c and the cooling viscous fan connect at 100 c.
In any case the engine should not exceed 107 c at any time otherwise you will distress it.
All the best
Tuercas viejas

 

[Tuercas viejas]

Hi,
Last night my car didn't start on first attempt and I got the Check Engine Light in dash.
It didn't start on 2nd attempt and on 3rd attempt it started but the Engine Light stayed on till I reached home.
The car started on 1st attempt after that but Engine Light stayed on.
In the morning the car didn't have any starting issues and started on 1st attempt with the engine light stayed on.
I took the car to dealer ship after that, when the restarted the car the light went off.
Anyway, they hooked computer to check for CEL errors logged and found out 'camshaft hal sensor error' and 'crankshaft position sensor'.
There is no engine light and is running fine now. Dealer also said there's nothing to worry about and after scanning a couple of times and test drive no errors were logged.

I have couple of questions to forum members:
Which part should I order camshaft hal sensor or CPS? Could any one send me part numbers of OM 647 engine.
My car overheated couple of weeks ago, could it be due to overheating?
Thanks

Azeem
Look at the head of the sensors and the part numbers will be displayed in embossed lettering.
I can give you part numbers we use for the engines we use here in the USA but the part might be different.
Regards
Tuercas viejas

 

[Azeem]

Thanks Tuercas viejas for your detailed reply. I'll look at the part numbers this weekend.

 

[Azeem]

Overheating

Tuercas viejas

The engine temperature has been a worry for the car lately.

On Climate control diagnostics (after a cold start) it jumps to 106-110 with AC running within 10 minutes of normal driving with ambient temperature in mid 30s.

How can I narrow down the culprit part, i.e. thermostat, Radiator, or viscous fan clutch?

Thanks in advance.

 

[Tuercas viejas]

Azeem
Greetings
This is a serious overheat condition.
Assuming you have no coolant leaks

The likely culprit(s) are the water pump not turning with sufficient speed under crankshaft belt drive.
Indicating belt tensioner , guide rollers or the accessory belt is worn and slipping
I find on this engine a high percentage of cooling complaints are caused by the accessory drive and in any case if the engine is close to 150, 000 kms on it the whole lot should be replaced.

Yes the thermostat is often found defective and not opening correctly, a common issue across the board on any MB vehicle with this engine installed.

Inspect and clean the radiator carefully both inside with a flush and outside the whole cooling pack using something like dishwashing liquid diluted to 50% with water. Apply to the separated cooling pack components A/.C condenser etc, in fact cleaning each cooler around the radiator as well.

When you refill the cooling system make site you have purged out ALL the air from the block and install a new pressure cap.

Then re-test the car to see how the system performs.
The engine should rise to 90c with about 10 minutes of driving under normal conditions and more or less stabilize. If you put a load into it like climbing a mountain grade at half throttle or above the car might heat to 100c where upon you should hare the viscous fan coupling kick in like what I call the Boeing effect of an aeroplane propeller cooling it down.
under no circumstance should the engine rise about 107 c on mountain grades even with ambients at 30 c. That is an overheat condition likely to cause long term head and piston damage..
If you can get a infrared heat gun shoot the top and bottom coolant hose connectors . There should be at least 8 to 9c difference between top and bottom of the radiator.

All the best
Tuercas Viejas

 

[Azeem]

Thanks again.
I did a radiator flush from inside a month ago.
It started with check coolant message in dash. My indie after inspection changed expansion coolant tank and the message disappeared. I changed the coolant with original MB 325.0 coolant 4.5 litres coolant mixed with distilled water. We did a radiator flush before putting the coolant. Purged the system by turning on the heater.
The engine temperature went upto 120C on kick down but the car drives fan at normal speed with AC on. I have been keeping a close eye on engine temperature by occasionally checking the AC diagnostics and coolant temperature in particular. (No. 6 option after running climate control diagnostics)
My indie asked me to consider changing the radiator but he wasn't sure that it would cure the problem. I am hesitant in spending $300 since he is not sure.
While the overheating issue was normalising, the car got into starting problem with CEL. On XEntry it showed camshaft hal and Crankshaft position sensor errors. The errors were gone on friday but this evening the car didn't start again. And check engine light came on again.
I am thinking that could all these issues be related? Is it possible that the sensors have gone bad due to overheating? I have to order these sensors from abroad (UK or Dubai probably) so I need to be sure that these are the parts that would solve the issue. Once i change the sensors and the car overheats again (since we haven't narrowed down the problem of overheating) then all effort of changing the sensors would go down the drain.
Thanks in advance.

 

[Azeem]

Tuercas Viejas
I ordered CPS, camshaft sensor and radiator (Behr) and they arrived last week.
I have changed the CPS and the car starts fine now. The throttle is more responsive now and is running great. I thought CPS was to address starting issues only. I will change the radiator and will update you.
Thanks again.