White smoke coming from exhaust?

[PhoenixBMW]

I seem to have intermittent white smoke coming from the exhaust that smells like raw gas? The engine oil light in the dash also sometimes flickers occassionally when I'm at idle not moving, anyone have any ideas what may be causing the smoke? It's a 1995 BMW 740iL i just bought to replace my former 91 3000GT

[04SSHD]

smoke or steam?

white smoke is usually a sign of water or condensation in the exhaust. Worse case is a blown headgasket, but you would be getting alot of white smoke comming out as your drive.

[PhoenixBMW]

Also, it isn't a head gasket problem because there is no overheating at all and everything appears to run just fine.

[PhoenixBMW]

smoke or steam?

white smoke is usually a sign of water or condensation in the exhaust. Worse case is a blown headgasket, but you would be getting alot of white smoke comming out as your drive.

I seem to randomly get some white smoke coming out when I press on the gas rather hard, but no overheating, my temperature stays perfectly in range, and the white smoke smells like raw fuel, doesnt have any burnt coolant smell or anything.

[AwesomeIsLuke]

Probably just steam.

The combustion in the engine yields H20 (water/steam) + CO2. That is why sometimes you'll see water dripping from the exhaust.

[PhoenixBMW]

Probably just steam.

The combustion in the engine yields H20 (water/steam) + CO2. That is why sometimes you'll see water dripping from the exhaust.

If it's steam, how come the smoke smells like fuel? And will this problem just go away on its own or is it going to keep doing this?

[AwesomeIsLuke]

If it's steam, how come the smoke smells like fuel? And will this problem just go away on its own or is it going to keep doing this?

Well, I think the oil light is unrelated because the smoke that oil produces is blue.

I'm not sure why it smells like fuel, but I think the steam wouldn't have anything to do with it.

Check your spark plugs, maybe one of your cylinders isn't firing correctly.

[PhoenixBMW]

Well, I think the oil light is unrelated because the smoke that oil produces is blue.

I'm not sure why it smells like fuel, but I think the steam wouldn't have anything to do with it.

Check your spark plugs, maybe one of your cylinders isn't firing correctly.

Ok, I'll go check them

[PhoenixBMW]

Well, I think the oil light is unrelated because the smoke that oil produces is blue.

I'm not sure why it smells like fuel, but I think the steam wouldn't have anything to do with it.

Check your spark plugs, maybe one of your cylinders isn't firing correctly.

You also mentioned that the oil light is un-related, could it possibly be the OSV then? I saw someone have similar problems here on bimmerforums just without the oil light and it was the OSV.

[AwesomeIsLuke]

You also mentioned that the oil light is un-related, could it possibly be the OSV then? I saw someone have similar problems here on bimmerforums just without the oil light and it was the OSV.

Maybe, but it doesn't explain your "raw gas smell" problem. You might have more than one issue at hand here.

[04SSHD]

OSV will give you lots of white smoke at startup. You can pull the engine oil dipstick and listen for a strong sucking sound. If you hear the sucking and it's very loud then your OSV is shot

[PhoenixBMW]

Maybe, but it doesn't explain your "raw gas smell" problem. You might have more than one issue at hand here.

The other thread mentioned a gas like smell as well.

[PhoenixBMW]

OSV will give you lots of white smoke at startup. You can pull the engine oil dipstick and listen for a strong sucking sound. If you hear the sucking and it's very loud then your OSV is shot

It is supposed to be very loud? I hear a sucking and its definitely pulling in air, but its not extremely loud or anything?

[04SSHD]

It is supposed to be very loud? I hear a sucking and its definitely pulling in air, but its not extremely loud or anything?

Light sucking is normal, heavy sucking is not.

[telijah]

The "OSV" issue is a rubbr diaphragm at the back of the intake manifold which tears and allows oil to enter the manifold before the air enters the valve. If it was the OSV, you should notice other symptoms. How long did the car sit before you bought it? Have you let it run out of gas and put fresh gas in?

[plik]

It smells like gas because you have fuel trim problems.

Do you live in Phoenix?

[PhoenixBMW]

The "OSV" issue is a rubbr diaphragm at the back of the intake manifold which tears and allows oil to enter the manifold before the air enters the valve. If it was the OSV, you should notice other symptoms. How long did the car sit before you bought it? Have you let it run out of gas and put fresh gas in?

The previous owner said it was his daily driver. The only other symptoms I have are the flickering oil light rarely while I'm idling, I haven't tried to put fresh gas in it yet, but I will go and try that today and put in some fuel cleaner.

[PhoenixBMW]

It smells like gas because you have fuel trim problems.

Do you live in Phoenix?

Oic, so would fresh gas and fuel cleaner fix the problem or what would I have to do? And unfortunately I don't live in Phoenix I live in Chapel Hill, NC, its near Raleigh.

[plik]

Oic, so would fresh gas and fuel cleaner fix the problem or what would I have to do? And unfortunately I don't live in Phoenix I live in Chapel Hill, NC, its near Raleigh.

Fresh gas and fuel cleaner won't do anything ... except fill your tank.

You probably have a vacuum leak, and I wouldn't be surprised if you need new O2 sensors.

Depending on what has already been replaced on the car, I would ...
- take of the manifold
- replace all manifold gaskets
- replace OSV (rear cover plate)
- replace O2 sensors (if they haven't been replaced recently)

And there's a long list of other things that I would do while I'm in there, but those should fix the problem.

You will need new spark plugs after your done -- the added fuel in the mixture will have fouled the plugs.

[PhoenixBMW]

Will driving the car as is right now damage it?

[plik]

Will driving the car as is right now damage it?

No, but it'll get worse.

Soon you will be billowing smoke out the back like a locomotive.

[PhoenixBMW]

Ok, I have looked up pretty much every OSV DIY I can find thus far, I plan to go to the dealership to get the parts needed to fix the OSV problem, my only question left is do I need to get the entire new OSV, or do I just need that orange thingy inside of it?

[plik]

Ok, I have looked up pretty much every OSV DIY I can find thus far, I plan to go to the dealership to get the parts needed to fix the OSV problem, my only question left is do I need to get the entire new OSV, or do I just need that orange thingy inside of it?

http://forums.bimmerforums.com/forum...d.php?t=905568

Read that thread.

And never go to the dealership for anything, especially parts.

In my opinion, you'll be much better off if you remove the entire manifold to get to the rear cover plate (osv), rather than trying to remove the rear cover plate with the manifold still in place.

Also, if the osv needs to be replaced, then it's most likely that every manifold gasket needs to be replaced, as well as the valley pan, etc., etc., etc. ....

[PhoenixBMW]

http://forums.bimmerforums.com/forum...d.php?t=905568

Read that thread.

And never go to the dealership for anything, especially parts.

In my opinion, you'll be much better off if you remove the entire manifold to get to the rear cover plate (osv), rather than trying to remove the rear cover plate with the manifold still in place.

Also, if the osv needs to be replaced, then it's most likely that every manifold gasket needs to be replaced, as well as the valley pan, etc., etc., etc. ....

Are their parts better than from the dealership? And I would want to do all the stuff that you mentioned, but unfortunately I don't really feel mechanically comfortable ripping parts off the engine, I have done work on a 318 and 325 before, but Im not familiar with the 740 engine at all. I just really want to get rid of this white smoke that keeps shooting out intermittently.

[PhoenixBMW]

O yea, and when I called the dealership, I was quoted $55 on the OSV and the parts guy said they didn't have a gasket for the OSV and said I didn't need one?