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How to go about diagnosing oil in coolant on 2012 car
Hi, can anyone help with documentation on how to approach the oil in coolant problem with the updated engine? I suspect it is the oil cooler gasket however, I cannot find the cooler.
I saw this excellent video however, my engine is different.
In the 08 model, the oil cooler is to the right of the oil filter
My engine is the M278 one where I suppose the gasket is actually behind the timing cover? I already have misfires on one cylinder bank. No coolant in oil but I think the engine maybe toast.
Last edited by peterkay; Feb 20, 2024 at 09:23 PM.
if the vehicle has a slight misfire and no other symptoms it could be lots of stuff - like a blocking CAT, leaky injector, failing coil stick, low compression, valve issue etc.
if you have a severe misfire it could be all of above allowed to continue - but it could also indicate something like a failing head gasket... as we have seen your diagnostics has thrown LOTS of misfire codes including one complete bank.... the physical present oil oil in the coolant, say from the oil cooler failing can't cause misfires....
those multiple misfires would start to point towards a head gasket failure - a compression test might help identify this.... as you know there seem to be issues it would be a sensible to do a simple test on all 8 and compare the results. They should never be below 10% of each other - and all cyl should hit (in old engines, newer high comp likely faster) 150PSI with two to three seconds of cranking - if you aren't getting over 120psi in 10 seconds of cranking you need to be thinking about pulling the heads off - and at that point you need to be thinking why bother - it needs a new engine....
modern cars are not these days built to be maintainable - and the bigger and more complex the part the more likely the best choice is save the stress and give up throw it in a skip and get another vehicle
its only old world thoughts that a weekend, a few tools and a can of beer and you end up with batter faster car.... this is a buying $300 of tools to get it apart, a week of hell, snapping some bolts you'll never get out, very likely finding the head and the block are toast... or waiting a month for $2000 of parts to assemble an engine where you know the heads and block are well past their sell by date
head gaskets
cam chain guides and tensioner
cam followers
its getting worse at a scary rate
the German philosophy since 2010 has been lease and throw it in a skip after 30 months
if the vehicle has a slight misfire and no other symptoms it could be lots of stuff - like a blocking CAT, leaky injector, failing coil stick, low compression, valve issue etc.
if you have a severe misfire it could be all of above allowed to continue - but it could also indicate something like a failing head gasket... as we have seen your diagnostics has thrown LOTS of misfire codes including one complete bank.... the physical present oil oil in the coolant, say from the oil cooler failing can't cause misfires....
those multiple misfires would start to point towards a head gasket failure - a compression test might help identify this.... as you know there seem to be issues it would be a sensible to do a simple test on all 8 and compare the results. They should never be below 10% of each other - and all cyl should hit (in old engines, newer high comp likely faster) 150PSI with two to three seconds of cranking - if you aren't getting over 120psi in 10 seconds of cranking you need to be thinking about pulling the heads off - and at that point you need to be thinking why bother - it needs a new engine....
modern cars are not these days built to be maintainable - and the bigger and more complex the part the more likely the best choice is save the stress and give up throw it in a skip and get another vehicle
its only old world thoughts that a weekend, a few tools and a can of beer and you end up with batter faster car.... this is a buying $300 of tools to get it apart, a week of hell, snapping some bolts you'll never get out, very likely finding the head and the block are toast... or waiting a month for $2000 of parts to assemble an engine where you know the heads and block are well past their sell by date
head gaskets
cam chain guides and tensioner
cam followers
its getting worse at a scary rate
the German philosophy since 2010 has been lease and throw it in a skip after 30 months
Thanks! Indeed very much like along the lines of what I thinking. I made a mistake. I thought that 2012 still came with the M273 engine which was somewhat reliable. Not really sure what to do about this car. I will try to do inspect the bores and do the compression testing on it this weekend. However, I suspect that it is either bore scoring or head gasket. Now, I was thinking about a used engine but looks like they are all going to fail. Anyone has done LS swap on these?
The camshaft sensors leak oil into the harness, especially on the M278 engines. Mine had the problem and caused a whole bank to misfire. Turned out that the oil leaked all the way into the Oxygen sensor and caused it to go bad, without codes.
After a thorough cleaning of the harness, new camshaft sensors, and a new oxygen sensor at my shop, the car is good as new. Have not had a problem in almost 20k miles.
The camshaft sensors leak oil into the harness, especially on the M278 engines. Mine had the problem and caused a whole bank to misfire. Turned out that the oil leaked all the way into the Oxygen sensor and caused it to go bad, without codes.
After a thorough cleaning of the harness, new camshaft sensors, and a new oxygen sensor at my shop, the car is good as new. Have not had a problem in almost 20k miles.
Oh, that is a brilliant idea to check! Thanks for the suggestion!
Here are the specific codes. Does it point to the camshaft sensor?
11.The position of the intake camshaft (cylinder bank 2) deviates from the specified value.There is an implausible signal.
12.Combustion misfiring of cylinder 1 has been detected.There is a signal above the permissible limit value.
13.Combustion misfiring of cylinder 4 has been detected.There is a signal above the permissible limit value.
14.Combustion misfiring of cylinder 2 has been detected.There is a signal above the permissible limit value.
15.Combustion misfiring of cylinder 3 has been detected.There is a signal above the permissible limit value.
16.Combustion misfiring has been detected.There is a signal above the permissible limit value. 17.The charge air temperature sensor (cylinder bank 1) has a short circuit to positive.There is a short circuit to positive.
Last edited by peterkay; Feb 22, 2024 at 09:25 AM.
this - 18.The outside temperature sensor has a short circuit to ground._
this MIGHT mean its worth checking for an Engine ECU update - around the time they were developing the later engine they were also inventing extras in software - one of them, discovered in the engine ECU caused arguments with the ambient temp sensor
this - 18.The outside temperature sensor has a short circuit to ground._
this MIGHT mean its worth checking for an Engine ECU update - around the time they were developing the later engine they were also inventing extras in software - one of them, discovered in the engine ECU caused arguments with the ambient temp sensor
Yes, I have noticed that the outside temp is pegged at 185 degrees on the instrument cluster. Houston is hotter than hell, but it is not that hot! I have bigger fish to fry at this moment so I will let it be for now.
Base on the codes you reported, I will focus on 11.The position of the intake camshaft (cylinder bank 2) deviates from the specified value.There is an implausible signal.
You can try first by swapping the camshaft position sensor between intake and exhaust. Delete ALL codes, run the engine and see if 11 comes back on the exhaust instead. If so, the sensor is busted --> new sensor. Alternatively, you can swap intake bank2 with intake bank 1, and check if the DTC follow the sensor.
Once you sort out 11, you follow the misfire. Fingers crossed it is this simple.
NOTE: while working around the sensors, follow @cruiser02 advice and check for oil at the connectors.
Base on the codes you reported, I will focus on 11.The position of the intake camshaft (cylinder bank 2) deviates from the specified value.There is an implausible signal.
You can try first by swapping the camshaft position sensor between intake and exhaust. Delete ALL codes, run the engine and see if 11 comes back on the exhaust instead. If so, the sensor is busted --> new sensor. Alternatively, you can swap intake bank2 with intake bank 1, and check if the DTC follow the sensor.
Once you sort out 11, you follow the misfire. Fingers crossed it is this simple.
NOTE: while working around the sensors, follow @cruiser02 advice and check for oil at the connectors.
Solid advice. I will do exactly that this weekend!
Edit: Do you reckon, I may as well order a new sensor and try it with it? It doesn't look very expensive. Part number 2769051000 if I not mistaken?
Last edited by peterkay; Feb 22, 2024 at 09:59 AM.
Solid advice. I will do exactly that this weekend!
Edit: Do you reckon, I may as well order a new sensor and try it with it? It doesn't look very expensive. Part number 2769051000 if I not mistaken?
It is up to you. However, please be mindful these engines have a few issues, and they can be a handful to sort out. Here is a recipe I have for myself:
0 - MB-aware scanner available (XEntry is best)
1 - Check codes, and sort them out first (in particular things related to camshaft sensor and/or solenoid, oil migration at connectors)
- REMINDER: the tone wheel can slip and could trigger a similar error as the camshaft position sensor. Especially if there was an engine rattle for a while.
2 - If still a misfire: swap coil first, nothing changes, swap plugs, nothing happens continue
4 - Boroscope before tearing down anything. These engines score cylinders
4 - Compression test or leak-down test
5 - Healthy cylinders, then, injectors come next. Swap, or if you have one spare. Just be careful not to introduce debris into the fuel rail, or bite an O-ring when putting them back
It is up to you. However, please be mindful these engines have a few issues, and they can be a handful to sort out. Here is a recipe I have for myself:
0 - MB-aware scanner available (XEntry is best)
1 - Check codes, and sort them out first (in particular things related to camshaft sensor and/or solenoid, oil migration at connectors)
- REMINDER: the tone wheel can slip and could trigger a similar error as the camshaft position sensor. Especially if there was an engine rattle for a while.
2 - If still a misfire: swap coil first, nothing changes, swap plugs, nothing happens continue
4 - Boroscope before tearing down anything. These engines score cylinders
4 - Compression test or leak-down test
5 - Healthy cylinders, then, injectors come next. Swap, or if you have one spare. Just be careful not to introduce debris into the fuel rail, or bite an O-ring when putting them back
I think I am pretty well set. I do have an authentic xentry setup - purchased from an EU-specific shop who bought it from an MB dealer.
I am planning to first do the xentry compression test since it is so easy. I will post results here before I do any openings.
Keep us updated! Hopefully soon you can enjoy this beast, everything from the build quality to the driving feel is amazing. Post some pictures when you get a chance too.
Well, I think it is all becomes clear. After the draining the coolant and refill with distilled water - white smoke and from the exhaust and this was the cold start and this is what I found leaking down behind the firewall. I think it is leaking oil + coolant from the plug where the lines go to the dash board.
1. The oil in the dipstick and filter are clear.
I think two things are evident:
1. Blown head gasket on driver side.
2. Failed gasket on the oil cooler.
I think at this point I will pull the spark plugs and inspect the bores. May need a new engine.
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