No-Start -- Head gasket diagnosis? -- updated w/comp test #s

[Half8]

My 318iS have well over 200k on the clock and an uncertain maintenance history.  I've had it for a year, and it has run like a champ the whole time.  After changing the oil on Sunday, it cranked fine, but would not turn over.  After trying again this morning, I found the coolant level to be way high (it overflowed when I removed the cap.)  The coolant is a translucent greenish -- not chocolate milk, but not clear blue either.  The oil level is about right for the oil I put in after the oil change.  Due to the coolant level, I'm fearing the head gasket or something similarly catastrophic has failed.  Are there any good shade tree diagnosis techniques I can do to confirm?
Thanks,

[Cobra Jet]

The greenish color of the coolant is most likely due to the prior owner(s) (or whatever shop they may have used) putting in just standard coolant (which is green).  The BMW coolant is blue and even w/ the proper mix of water added, it still would be blue than green.

As far as not starting, there are a few things that could cause a non-start:

fuel pump not turning on (or priming)
bad fuel pump relay
crank positioning sensor is bad
no spark

I would pull codes and it's easy enough to do:

You can pull codes by turning the key to "on" (KOEO - key on engine off) and you will then need to press down the gas pedal 5 times consecutively within 5 seconds. If you depress the gas pedal too slow or too fast, you won't get the CEL (check engine light) to blink in the dash cluster... If you do it correctly, what will happen next is the CEL will start to blink any stored codes. You will need to count the CEL flashes and then once you have the codes, you can determine what may be causing any problems...

For instance, if there are no faults or stored codes, the CEL will produce:
blink -pause- blink, blink, blink, blink -pause- blink, blink, blink, blink -pause- blink, blink, blink, blink (this is the no fault code of "1444").

Get yourself a pen & paper to write down what the CEL does.

Here is a link to the Motronic codes: http://ee1394.com/bmw/docs/bmwDTCodes.pdf

If the vehicle was running perfectly fine prior to your oil change, I would not suspect a head gasket just yet...  When you changed the oil, was it just oil coming out, or did you see any sort of "milky" mixture?  If the coolant is all green and you do not see any suspended oil in it, then it should be ok.  It is also quite possible that if you have never checked the coolant level in the past that maybe the prior owner (or again whatever shop they may have been dealing with) overfilled the cooling system.  The tank on the side of the radiator when COLD should only be leveled out at the "cold" fill mark on the tank.  Also, the rad tank should not be 100% completely full up to the cap, as there needs to be some space for the coolant to expand, etc when the vehicle is running and at normal operating temps.  

A bad crank sensor will not allow the car to start at all, the engine will turn over and keep cranking, but it will never start.

A bad fuel pump (or fuel pump relay) - when turning on the vehicle, you will not hear any fuel pump prime (which is a slight mechanical whine or hum).  You should be able to heard this hum/whine when just turning the key to ON w/o actually starting the car.  Some fuel pumps are louder than others, so you may have to remove the bottom of the rear seat cushion (if doing this procedure yourself).  If you have a buddy, have them turn the key on while you go to the passenger side near the B pillar (middle of car), get down on the ground and listen outside of the car for the fuel pump prime/whine.

Even if the car had a bad head gasket (one that was starting to fail), it would still start up.  If the engine was hydro-locked due to a major head gasket or coolant failure, the engine would not turn over freely at all (manually by turning the crank or by trying to start it with the key).

[Half8]

The greenish color of the coolant is most likely due to the prior owner(s) (or whatever shop they may have used) putting in just standard coolant (which is green).  The BMW coolant is blue and even w/ the proper mix of water added, it still would be blue than green.

As far as not starting, there are a few things that could cause a non-start:

fuel pump not turning on (or priming)
bad fuel pump relay
crank positioning sensor is bad
no spark

I would pull codes and it's easy enough to do:

You can pull codes by turning the key to "on" (KOEO - key on engine off) and you will then need to press down the gas pedal 5 times consecutively within 5 seconds. If you depress the gas pedal too slow or too fast, you won't get the CEL (check engine light) to blink in the dash cluster... If you do it correctly, what will happen next is the CEL will start to blink any stored codes. You will need to count the CEL flashes and then once you have the codes, you can determine what may be causing any problems...

For instance, if there are no faults or stored codes, the CEL will produce:
blink -pause- blink, blink, blink, blink -pause- blink, blink, blink, blink -pause- blink, blink, blink, blink (this is the no fault code of "1444").

Get yourself a pen & paper to write down what the CEL does.

Here is a link to the Motronic codes: http://ee1394.com/bmw/docs/bmwDTCodes.pdf

If the vehicle was running perfectly fine prior to your oil change, I would not suspect a head gasket just yet...  When you changed the oil, was it just oil coming out, or did you see any sort of "milky" mixture?  If the coolant is all green and you do not see any suspended oil in it, then it should be ok.  It is also quite possible that if you have never checked the coolant level in the past that maybe the prior owner (or again whatever shop they may have been dealing with) overfilled the cooling system.  The tank on the side of the radiator when COLD should only be leveled out at the "cold" fill mark on the tank.  Also, the rad tank should not be 100% completely full up to the cap, as there needs to be some space for the coolant to expand, etc when the vehicle is running and at normal operating temps.  

A bad crank sensor will not allow the car to start at all, the engine will turn over and keep cranking, but it will never start.

A bad fuel pump (or fuel pump relay) - when turning on the vehicle, you will not hear any fuel pump prime (which is a slight mechanical whine or hum).  You should be able to heard this hum/whine when just turning the key to ON w/o actually starting the car.  Some fuel pumps are louder than others, so you may have to remove the bottom of the rear seat cushion (if doing this procedure yourself).  If you have a buddy, have them turn the key on while you go to the passenger side near the B pillar (middle of car), get down on the ground and listen outside of the car for the fuel pump prime/whine.

Even if the car had a bad head gasket (one that was starting to fail), it would still start up.  If the engine was hydro-locked due to a major head gasket or coolant failure, the engine would not turn over freely at all (manually by turning the crank or by trying to start it with the key).

Thanks for the great post.  The coolant level was right at the cold mark before I tried to start it.  I'll check the codes when I get home tonight.

[Half8]

Thanks for the great post.  The coolant level was right at the cold mark before I tried to start it.  I'll check the codes when I get home tonight.

I couldn't get the stomp test to work, but I jiggled the fuel pump relay, which seemed to have been a little loose.  It clicked with the key on.  The engine cranked, fired very briefly, then died.  I could smell gas, so I think the fuel pump is at least partially working.  Yesterday, it wouldn't fire at all, and there was no smell of gas.

Yesterday, I drained coolant down to the cold fill level.  Today, after attempting to start the car, coolant poured out of the overflow tank when I removed the radiator cap, and remained all the way up to the neck of the overflow tank.  The coolant looks clear, with no suspended oil, or oily residue at the top, and the oil level has remained constant.

I'll go through the fuel pump/relay tests to see whether there's an issue there.  But does anyone have an idea as to what would cause the coolant level to continue to rise even though the engine remains stone cold?

[Cobra Jet]

The gas pedal test is finicky, as if you press the pedal too fast consecutively or too slow, it won't trigger the CEL to flash...  Try it again.  Turn the key on (not trying to start to the car), once you turn the key on, press down the pedal 5 times in a row, trying to keep the "rythm" the same.  You should be able to get it to work.

This may be far fetched, but pull your spark plugs and once pulled, see what each of them looks like.  When was the last time they were changed?  If you have a high powered flashlight, before installing the plugs again, see if you can peer down into the cylinder and see if you can see ANY type of fluid within the cylinder.  My guess is you're not going to find any fluid, but it's just another "check" to verify that coolant has not breached the cylinders.  If the plugs are old and based on what you see when you pull them out, it's possible the plugs are fouled too.

My guess is the fuel pump relay may need to be replaced IF the vehicle tried to start after you did the "wiggle" with it.  Either that or the connection (wire harness) that goes to it needs to be looked at again.  If after wiggling the relay and you attempt to start it again, while trying to start it, press down on the gas pedal and see if it will either keep an idle (if it starts) or if you can coax it into starting.

When was the last time the ICV of AFM was cleaned?

If the car was running fine before you did the oil change, it's just a coincidence that another part has either failed or is failing.

Any overheating issues prior to the oil change?  Any other abnormal issues you can think of that occured prior to the oil change?

When was the last time the fuel filter was replaced?

[twinpop171]

Yesterday, I drained coolant down to the cold fill level.  Today, after attempting to start the car, coolant poured out of the overflow tank when I removed the radiator cap, and remained all the way up to the neck of the overflow tank.  The coolant looks clear, with no suspended oil, or oily residue at the top, and the oil level has remained constant.

I'll go through the fuel pump/relay tests to see whether there's an issue there.  But does anyone have an idea as to what would cause the coolant level to continue to rise even though the engine remains stone cold?

The raising coolant level worries me.  It sounds like compression is getting into the cooling system when you are cranking the engine. The compression would push the coolant towards the path of least resistance.  Good luck and keep us posted.
Dan.

[Half8]

The raising coolant level worries me.  It sounds like compression is getting into the cooling system when you are cranking the engine. The compression would push the coolant towards the path of least resistance.  Good luck and keep us posted.
Dan.

Upon returning home last night, I checked the coolant level before attempting to start the car.  The coolant remained pressurized, and overflowed when the cap was removed.  The car started and remained running on the first try.  I drove it a few miles and filled up the gas tank.  The temp needle fluctuated from the 3/4 hot mark to below the 12 o'clock position.  Other than that, everything seemed fine.  The engine ran strong, and had no problems re-starting.  

This morning, the coolant level was very low, as it probably should be after all that I drained and/or overflowed on its own.  There was a strong smell of gas in the overflow tank.  The oil level remained where it had been.  The car started on the first try, and ran fine.

Any ideas on what would cause gas to get into the coolant?

[twinpop171]

Any ideas on what would cause gas to get into the coolant?

Doesn't sound good.  You're instincts may be right with the head gasket considering all of the other symptoms.
Good luck.
Dan.

[bmwpower]

Gas smell in coolant = combustion gases getting into coolant = cracked head

Ask me how I know.  

http://www.m42club.com/forums/showthread.php?t=3375&highlight=head

Do a compression test.

[Half8]

The car has been starting and running fine for a few days. I've only driven it for a few 1-mile trips, but the coolant temp gauge has remained a hair below 12 o'clock, which is where it used to settle in.
 
I pulled the plugs and did a compression test today. #1 - 165, #2 - 148, #3 - 165, #4 - 185. The plugs are pictured below. 1 and 3 had some oil on them; 2 and 4 were dry and normal-looking. (#1 is on the far left, #4 is on the far right.) Can anyone read these tea leaves and tell me whether the engine is in imminent danger of catastrophic failure, or whether it's something that will slowly get worse.
 
 

 

Gas smell in coolant = combustion gases getting into coolant = cracked head
 
Ask me how I know.
 
http://www.m42club.com/forums/showthread.php?t=3375&highlight=head
 
Do a compression test.

[bmwpower]

Is this a hot or cold compression test?

There's 20% between the lower and upper values for compression - the engine is borderline as far as compression goes.  Might try it again with a little bit of oil in the cylinder to see if it's the rings.

[Half8]

Re-tested again tonight, at full operating temp.

Dry test:
#1 - 160 #2 - 155 #3 - 165 #4 - 180
Wet test:
#1 - 180 #2 - 185 #3 - 200 #4 - 205

The car is running fine, with no obvious loss of power.  Any ideas on what I'm in for?

Is this a hot or cold compression test?

There's 20% between the lower and upper values for compression - the engine is borderline as far as compression goes.  Might try it again with a little bit of oil in the cylinder to see if it's the rings.

[bmwpower]

How did the plugs look after the hot test?  Same?

I don't see any signs of coolant getting in the oil/chamber.  You would see coolant in the oil and clean plugs - you're not seeing that - unless it shows up with the plugs after heating them up to operating temp.

I would do a coolant pressure test or at least put a gauge on it to see what the pressure is when running normal temp.

How old is the thermostat?