84 old air filter problem
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84 old air filter problem
01-02-2009, 07:34 PM
I have an 84 cutlass supreme, has a 3.8 litre. Car seems to run fine, but I have to change the air filter to often. It has fuel on it. I don't know if the carb needs to be rebuilt or I have some other possible problem. There isn't any liquid fuel in the breather housing just in the filter. I have noticed the idle air control clicking which I haven't noticed before. Don't exactly know how to test it. Vacuum is good around 20. Timing is on. Car has about 70000 original miles. It was my mothers and sit in the garage quite a bit, my daughter drives it now so I need to get it fixed before a possible fire. Thanks.
01-05-2009, 02:16 PM
Are you sure it's fuel?
Gasoline tends to evaporate very quickly and leave no trace. A splash of gas on the filter will dry up and disappear in easily within a minute or two. Unless the filter is actually soaked in gasoline which readily dries up in a few minutes, I do not think you have a problem, other than a possible defective PCV valve.
If you find the filter looks stained and smells somewhat like gas/oil, you are probably seeing the result of crankcase gases that have been ducted into the aircleaner. This is normal in older, higher mileage engines.
Any engine will produce a fog of oil vapor and partially burned hydrocarbons (blow-by gases) in the crankcase when running. Older, more worn cars like yours produce more gases than new cars.
A measured amount of these gases are sucked into the intake manifold through the PCV valve to be burned in the engine. This reduces pollution and prolongs engine and oil life.
When the engine produces more gases than can be sucked in (common in old engines), the excess gases are ducted into the air cleaner.
The gases typically stain the airfilter and make it smell of gasoline and oil.
This is normal up to a point. If it's excessive, your PCV valve is stuck or blocked and needs to be replaced. They are very inexpensive and easy to change. If you change it, make sure the tube itself is clean inside.
01-05-2009, 08:31 PM
I forgot about the PCV. I will change the pcv valve and filter and see if that helps. Thanks. I can feel gas when I put my hand over the carb. My hand doesn't have to be touching the carb. It can be an inch or so above. At times you can even see sprinkles of gas just above the carb. I have an old pickup and I can't see or feel gas on it, so I am stumped.
01-06-2009, 11:02 AM
At times you can even see sprinkles of gas just above the carb. .
Okay, the only way for this to happen is if raw gas is being pushed out of the carburetor's bowl vent. This occurs when the carb is being overfilled with gasoline.
Possibly the carb's "needle and seat" valve no longer seals properly and/or the float has 'sunk', by becoming so saturated with gas it no longer floats properly.
In this case, rebuild the carb. Be sure to get a new float, too and make sure the float level is set according to the rebuild kit's instructions.
01-07-2009, 07:17 PM
Thanks I'll give that a try. I was afraid the carb needed to be rebuilt. I've done it before, but its been a while. Wasn't really looking forward to that.
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