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Car: BMW 1999 - 2006 E46 CCV Issues

BMW 1999 - 2006 E46 3 Series
Models: 320i, 328i, 325Ci, 330Ci, 325i

BMW has a special PCV valve designed called CCV valve, and has been using up to 2006 model.

This CAD$200 valve is one of the parts fall under routine maintenance every 6 - 10 yr, and especially important in cold climate like Canada where temperature drops to - 15 C or colder.  Another part which closely related to CCV functionality is coolant thermostat which again has the similar life span and fall under same routine maintenance schedule.

This blog post provided some important points to identify failures which could lead to engine hydrolock under various scenarios, and not limited to CCV valve.  So call "hydrolock" here referring to the CCV valve is stuck due to ice build up inside the valve body (not the 4 hoses connecting to it), which is causing CCV to suck the engine oil from the dipstick all the way into intake port, and flooding the combustion chamber (piston head) and causing all 6 pistons to be wet and covered with engine oil.  The engine oil will eventually able to travel through the entire exhaust system from combustion chamber, 6 spark plugs, exhaust header, 4 O2 sensors, catalytic converter, resonator (for 330Ci only), tail pipe, and engine oil dripping from tail pipe.  The fatal problem is that the car will able to start in -15 C or colder for few minutes, then shortly engine will be dead (unable to turn), and requires a toll truck.

The financial impact to fix the hydrolock will be as much as CAD$1000 - CAD$1650 with following cost breakdown with 1 - 2 days of repair.  Most of the parts are contaminated by engine oil:

  1. CCV valve - CAD$200 BMW, or CAD$120 OEM
  2. engine valve cover gasket - CAD$26
  3. 6 spark plugs - CAD$65
  4. 4 O2 sensors - CAD$230
  5. Intake valve gasket - CAD$10
  6. Labor charge - Assuming CAD$75/hr, CAD$600@8 hr to CAD$1200@16 hr.  Mainly for CCV and cleanup engine oil from combustion chamber and intake valve
  7. Catalytic converter - CAD$800 ($400 each)

All of these are able to be done DIY to save the labor cost, but still cost at least CAD$525 to repair.  Luckily the minimum amount of work to make the car drive-able is just the CCV and such up the engine oil from each piston (have to do about 10 times).

The most important point to focus here is to prevent engine hydrolock by keeping optimal engine temperature.

Following are the components involve in all parts related to causing engine hydrolock, but excludes above  parts which might need to be replaced after affected by hydrolock, and their location:

  1. Heater core temperature sensor - located behind the climate control unit, and accessible by removing the gear switch cover and lower storage compartment.  Cost CAD$22
  2. Coolant engine temperature sensor - located below last intake port (near to windshield), but rarely an issue.  Cost $20
  3. Lower coolant hose temperature sensor - located on lower left coolant hose, and easily reachable below the aux fan connector.  Cost $30
  4. Coolant thermostat - located next to engine oil filter and below one of the CCV hose.  Common failure. Cost $80
  5. CCV valve - below the intake valve and behind the throttle body valve.  Common failure.  Cost $200 BMW or $120
  6. Concentrate coolant - Cost CAD$25
First, you will need BMW INPA software to fully identify all the potential problems.  Torque or regular OBD2 reader will not able to read all the temperature sensors temperature

Component 1: Coolant thermostat
  1. This is the first component to isolate for improper engine temperature
  2. Disconnect the electrical connector, and turn off the fan completely
  3. Start the engine, and let it run idle for 10 min, or drive it around for 10 min
  4. Observe the coolant temperature (assuming the parts if not faulty) from INPA, or engine temperature gauge from dashboard (less accurate)
  5. Ensure it hits 95 - 96 C consistently
  6. The heater can on and fan can be at lowest setting (not auto mode), and engine coolant temperature should still at 95 - 96 C
  7. If heater on at full fan speed, the temperature will be 91 C and higher
  8. Connects the electrical connect back to thermostat, and start the engine as soon as possible
  9. If it can remains at 95 - 96 C at idle engine, it passed the optimum engine temperature at idle
  10. Drive the car around for 10 min, without turn on the fan, and observe its temperature still maintain at 95 - 96 C
  11. If it can maintain the temperature, then this parts works as well as the rest of the temperature sensors.  You can skip the remaining troubleshooting and jump directly to CCV valve
  12. Typical failure is soft failure, where the temperature cannot reach 90 C with idle engine and no heater.  For example only can reach 50 C, or 80 C max.  If this is the case, then this part is bad, and require replacement before proceed to diagnose other parts
  13. A side effect of engine coolant temperature cannot exceed 80 C (optimal is 96 C) is that the yellow goo does not build up in engine oil fill cap
  14. A non scientific ways (if you don't has INPA software or OBD2 reader) to know whether to know whether engine coolant temperature is above 90 C on cold climate (says below 10 C) is to drive the car with heater on full fan speed for 30 minute and turn on the fan on central air vent (central air temperature knob on 3 dots red color).  Uses your fingers to touch the central air vent and it should be painfully hot to the touch

Component 2: Lower coolant hose temperature sensor
  1. Read the sensor temperature on cold engine
  2. If the temperature is > 10 C different than outdoor temperature, then replace it
  3. Run the engine for 10 min and read sensor temperature again
  4. If it is < 50 C, then replace it
  5. Remove the electrical connector to this sensor to simulate hot coolant temperature to trick the DME computer to turn on AUX fan in front of radiator (not the main radiator fan behind the radiator).  This will reduce the engine coolant temperature

Component 3: Engine coolant temperature sensor (below last intake port)
  1. Read the sensor temperature on cold engine.  It should be 5 - 15 C higher than outside temperature.  Cold engine temperature accuracy is not important, so don't replace it simply because it is 20 C higher than outside temperature
  2. Start the engine, and observe the temperature increase.  This reading can be from any OBD2 reader, including Torque cellphone app
  3. It should raise every minute, and will reach 96 C before start dropping to 91 C (with heater fan on full speed), or maintaining at 95 - 96 C (with fan off)
  4. The hot engine temperature must be accurately reads 95 C - 96 C (without heater fan turn on).  If it is not, then disconnect the electrical connector in thermostat to force the temperature reaching 96 C.  Its reading must reach 95 C - 96 C, unless bad thermostat
  5. If thermostat is good, and it cannot read 96 C, then this sensor is bad.  Replace this CAD$20 sensor
  6. Bad sensor that reads high temperature, or disconnecting the electrical connection will cause the sensor reading in OBD2 reader and dashboard to read max temperature, and will turn on the thermostat to reduce engine coolant temperature to 72 C max
  7. This sensor can be removed by using:
    1. 22 mm 3/8" 12-points socket (not deep socket) like this
    2. Modified open 22 mm wrench like this
    3. 22 mm wrench like this
    4. S-type 22 mm wrench like this
    5. 22 mm 3/8" socket with joint socket adapter (prefer 1/4" adaptor) like this
Component 4: Heater core temperature sensor
  1. This is another reliable temperature sensor located behind climate control unit, and easily accessible to replace it or disconnect it (for troubleshooting) by removing following 2 components
    1. Gear shift cover (2 screws next to gear shift, and 2 screws on the dash)
    2. Small storage bin below the climate control IHKA panel
  2. Only INPA software can read the heater core temperature
  3. With cold engine, read its value, and its value should be 5 - 10 C similar to cabin temperature
  4. Turn on the engine, and set the fan to AUTO mode
  5. Watch the temperature slowly change every minute
  6. Its temperature should reach maximum of 92 C after 15 min with idle engine or 5 min driving.  If it took longer, there might be failure on other components, but should not be this sensor, unless it is loose, and not tightly attach to the box (heater core box)
  7. Disconnect the electrical connector (the cable is green color) to force the thermostat to turn on.  This will keep the engine coolant temperature at 70 C instead of 96 C
  8. If this sensor is missing, or reporting high temperature on warm engine, then it is bad, and need replacement
  9. This component cost ~ CAD$22 and can be any brand found in eBay, so don't waste money to buy BMW brand
Component 5: CCV valve
  1. This component does not affect engine coolant temperature, but only will cause high engine oil consumption (if engine coolant temperature can reach 96 C), or engine hydrolock (if engine coolant  temperature couldn't reach 96 C)
  2. First, ensure engine coolant temperature can reach 96 C.  Resolve this first before looking into CCV troubleshooting
  3. Open the engine oil fill cap on top of engine to see whether it has yellow goo
  4. If you are reading this post just for preventive maintenance or prevention only, and not to fix a problem, then you can eliminate the yellow goo by using any of following options
    1. In winter where temperature below 0 C, remove radiator fan that connects to water pump completely.  Store it and only re-attach it in summer
    2. In winter, cover the front grill with paper board to reduce the air flow to cool down the engine.  Just let the coolant radiating heat through radiator
    3. After each drive, remove the engine oil fill cap
    4. After each drive, disconnect the CCV valve connecting to valve cover (don't use this method if your CCV is old, because the plastic tube will break easily after 10 yr but will last longer for cold-climate model)
  5. Remove the CCV hose connecting to valve cover.  If you see there are lots of yellow goo build up on the wall and they are harden, the simplest way is to replace the entire CCV + hose
  6. A more time consuming method is to clean them
    1. Disconnect both CCV hose connecting to air distribution unit on top of engine which is connecting to intake valve body
    2. Stuck some cloth/paper to cover those 2 hose, or attach both hose to a grocery plastic bag
    3. Disconnect the CCV hose connecting to engine oil dipstick
    4. Connect this hose to engine oil container or a 2 - 4 liter catch can of any type
    5. Uses a funnel to pour camping stove fuel, coleman fuel, gasoline, white gas, naphtha, acetone, or auto transmission oil (more expansive) into the CCV hose connecting to valve cover.  You will need to buy 12 mm vacuum hose for this job, or funnel with flex tube
    6. The liquid will come out from the lower CCV hose (to the dipstick).  Let it drip for about 100 ml then cover the hose
    7. Fill up the liquid again, and let settle for 1 day
    8. Drain everything out
    9. Look through the hose again to ensure all the goo are gone.  If not, repeat step 5 and drain it another day
    10. Optionally use compress air to blow through each hose.  If the goo is soft, then the compress air is the quickest approach.  If it is harden, then using liquids to melt the goo is more efficient
    11. If transmission oil is used, then I recommend to fill it once with naphtha or acetone which dry up very fast (less than 5 min)

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