Gas smell from oil filler tube?
#1
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Hello,
99 C4 with 112000+ miles
No leaks but car uses about 1 qt of oil every 5000 miles.
Recently while adding oil (car fully warmed up), when I removed the oil filler cap...I smelled gasoline (and saw steam) coming from the oil filler tube.![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
Any ideas what is happening? Is this normal?
thanks in advance.
rglee
99 C4 with 112000+ miles
No leaks but car uses about 1 qt of oil every 5000 miles.
Recently while adding oil (car fully warmed up), when I removed the oil filler cap...I smelled gasoline (and saw steam) coming from the oil filler tube.
![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
Any ideas what is happening? Is this normal?
thanks in advance.
rglee
#2
Three Wheelin'
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Well I am not an expert, but I am gathering that the smell of gas (fuel) is the oil itself. As for the steam. not sure.
How hard were you driving the car prior to topping off the oil?
How hard were you driving the car prior to topping off the oil?
#5
Race Director
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Hello,
99 C4 with 112000+ miles
No leaks but car uses about 1 qt of oil every 5000 miles.
Recently while adding oil (car fully warmed up), when I removed the oil filler cap...I smelled gasoline (and saw steam) coming from the oil filler tube.![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
Any ideas what is happening? Is this normal?
thanks in advance.
rglee
99 C4 with 112000+ miles
No leaks but car uses about 1 qt of oil every 5000 miles.
Recently while adding oil (car fully warmed up), when I removed the oil filler cap...I smelled gasoline (and saw steam) coming from the oil filler tube.
![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
Any ideas what is happening? Is this normal?
thanks in advance.
rglee
There's always a bit of water in engine oil -- water is a normal contaminant of engine oil -- and hot oil will be outgassing this water vapor.
Considerable water can build up in engine oil if car used for short trips and in colder weather, humid weather. If this was the first long distance drive that got the engine nice and hot, there can be alot (relatively speaking) water in the oil.
(BTW, it is this water vapor and the relatively cool area at the top of teh oil filler tube/cap that can see the white stuff collect under the cap. Water vapor rises and contacts this colder hardware and condenses on it where it sort of combines with any oil vapor that also can condense there.)
Anyhow, if you have continued to run the engine this water vapor would have been pulled out of the crankcase and directed to the intake and ultimately sent through the combustion chambers and out the exhaust and chances are you would not have seen anything.
The same with gasoline. Some gasoline injected into the combustion camber will not burn, and some of this unburned gas makes its way into the oil.
As with water vapor if the oil gets hot enough this gasoline will be heated enough to leave the oil as vapor and as the engine continues to run this vapor is routed back through the engine and is burned.
However, I'm always concerned about gasoline smells and would want to be very sure the smell is not from a leak somewhere.
I'd keep a close eye and nose on the engine and regularly check the engine compartment and around the car for any more signs of gasoline smell and if I detected any I'd consider having the fuel system checked for any signs of any gas leakage. A gas leak can turn real serious. Not a few cars burn to the ground -- sometimes taking the garage/attached house with them -- from ignored gasoline leak.
Sincerely,
Macster.
#7
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if in colder climes.
There's always a bit of water in engine oil -- water is a normal contaminant of engine oil -- and hot oil will be outgassing this water vapor.
Considerable water can build up in engine oil if car used for short trips and in colder weather, humid weather. If this was the first long distance drive that got the engine nice and hot, there can be alot (relatively speaking) water in the oil.
(BTW, it is this water vapor and the relatively cool area at the top of teh oil filler tube/cap that can see the white stuff collect under the cap. Water vapor rises and contacts this colder hardware and condenses on it where it sort of combines with any oil vapor that also can condense there.)
Anyhow, if you have continued to run the engine this water vapor would have been pulled out of the crankcase and directed to the intake and ultimately sent through the combustion chambers and out the exhaust and chances are you would not have seen anything.
The same with gasoline. Some gasoline injected into the combustion camber will not burn, and some of this unburned gas makes its way into the oil.
As with water vapor if the oil gets hot enough this gasoline will be heated enough to leave the oil as vapor and as the engine continues to run this vapor is routed back through the engine and is burned.
However, I'm always concerned about gasoline smells and would want to be very sure the smell is not from a leak somewhere.
I'd keep a close eye and nose on the engine and regularly check the engine compartment and around the car for any more signs of gasoline smell and if I detected any I'd consider having the fuel system checked for any signs of any gas leakage. A gas leak can turn real serious. Not a few cars burn to the ground -- sometimes taking the garage/attached house with them -- from ignored gasoline leak.
Sincerely,
Macster.
There's always a bit of water in engine oil -- water is a normal contaminant of engine oil -- and hot oil will be outgassing this water vapor.
Considerable water can build up in engine oil if car used for short trips and in colder weather, humid weather. If this was the first long distance drive that got the engine nice and hot, there can be alot (relatively speaking) water in the oil.
(BTW, it is this water vapor and the relatively cool area at the top of teh oil filler tube/cap that can see the white stuff collect under the cap. Water vapor rises and contacts this colder hardware and condenses on it where it sort of combines with any oil vapor that also can condense there.)
Anyhow, if you have continued to run the engine this water vapor would have been pulled out of the crankcase and directed to the intake and ultimately sent through the combustion chambers and out the exhaust and chances are you would not have seen anything.
The same with gasoline. Some gasoline injected into the combustion camber will not burn, and some of this unburned gas makes its way into the oil.
As with water vapor if the oil gets hot enough this gasoline will be heated enough to leave the oil as vapor and as the engine continues to run this vapor is routed back through the engine and is burned.
However, I'm always concerned about gasoline smells and would want to be very sure the smell is not from a leak somewhere.
I'd keep a close eye and nose on the engine and regularly check the engine compartment and around the car for any more signs of gasoline smell and if I detected any I'd consider having the fuel system checked for any signs of any gas leakage. A gas leak can turn real serious. Not a few cars burn to the ground -- sometimes taking the garage/attached house with them -- from ignored gasoline leak.
Sincerely,
Macster.
I don't think its water vapor because most of my drives are 20+ miles.
So I don't think I would have enough water accumulated.
This was the first time I added oil to a warm engine (I usually add it when cold) so I don't know exactly how long this has been occurring.
Also, I just recently began to smell gasoline after stopping but the occurrence is sporadic with no recurring frequency (maybe twice month for the past 2 months).
I want my mechanic to take a look but because I can't seem to repeat the problem it is hard.
Thanks for the warning.
I'll probably just bring it in and have my mechanic take a look.
Thanks again.
rglee