I was just woundering when an engine is worn out does the oil usually come back threw the intake pipe. Cause I took the intake pipe off and there is oil in it. Is the engine worn out(it does have over 210,000 miles on it), or is there something else wrong with it? I did a head swapp on it a year and a half ago. Could there be something I did? The cylinders had very good cross hatch and it runs very good. I have to add a quart of oil about every 2weeks. And it only smokes when I lay into the throttle WOT. and that is because there is oil in the intake. Thanks for the help. and hoping there is a simple fix for it or if I just have to live with it.
96 GT using oil.
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wmburns
SN Certified Technician
IMO, to say a motor is worn out more information is needed. What is the result of a compression test and leak down test? How is the car driven? How is the power? How is the gas mileage? What mods have been done?
It is normal for a small amount of oil to be in the intake. The oil is blow by from the PCV system. The oil becomes a problem when it is excessive. How much oil denotes excessive depends upon HOW the motor is used. For example, excessive oil blow by in a racing or high HP application my reduce the octane level of the fuel causing detonation.
A regular street driven car can tolerate higher level of oil in the intake.
How much oil are you using (in miles per quart)? For a normal street driven car, start being concerned if the oil consumption is much worse than 1000 miles per quart. Again, this is a personal preference item. At 1000 miles per quart, plugs will foul more frequently.
At the 500 miles per quart level, there will most likely be excessive smoking and gas mileage will suffer.
It is also possible to add an external oil separater to reduce the amount of blow by oil in the intake.
It is normal for a small amount of oil to be in the intake. The oil is blow by from the PCV system. The oil becomes a problem when it is excessive. How much oil denotes excessive depends upon HOW the motor is used. For example, excessive oil blow by in a racing or high HP application my reduce the octane level of the fuel causing detonation.
A regular street driven car can tolerate higher level of oil in the intake.
How much oil are you using (in miles per quart)? For a normal street driven car, start being concerned if the oil consumption is much worse than 1000 miles per quart. Again, this is a personal preference item. At 1000 miles per quart, plugs will foul more frequently.
At the 500 miles per quart level, there will most likely be excessive smoking and gas mileage will suffer.
It is also possible to add an external oil separater to reduce the amount of blow by oil in the intake.
The car runs good. I don't drive no more than 500 miles before it uses a quart of oil and none of the plugs have ever fouled out. and the gas mileage is still good. There is a good bit of oil in the intake. Would the oil seperator stop the use of oil?
wmburns
SN Certified Technician
Short answer is no.
Various ppl make PCV oil separators (Steeda for example). However, it is completely unreasonable to expect such a product to remove ALL of the oil ALL of the time.
An oil separator capable of removing ALL oil would be a large race quality piece with mesh screen, baffles, chambers, sump, and a means to cool the vapors to encourage condensation.
Consider that the answer to the question about excessive oil consumption is in your reply. If the plugs do not foul, then the oil consumption can not be excessive (for a stock street driven car)
Various ppl make PCV oil separators (Steeda for example). However, it is completely unreasonable to expect such a product to remove ALL of the oil ALL of the time.
An oil separator capable of removing ALL oil would be a large race quality piece with mesh screen, baffles, chambers, sump, and a means to cool the vapors to encourage condensation.
Consider that the answer to the question about excessive oil consumption is in your reply. If the plugs do not foul, then the oil consumption can not be excessive (for a stock street driven car)
patman0911
Founding Member
Yeah, if you're not fouling plugs, and the performance, driveability and gas mileage is still acceptable then keep driving it and don't look back (at the cloud of smoke you're leaving behind you 
). You might start saving pennies for an eventual rebuild or motor swap though.
). You might start saving pennies for an eventual rebuild or motor swap though.Just a question related to this - in general, how does oil end up in the intake pipe? I'm assuming it is going through the PCV valve.
I've heard that a bad PCV can let oil end up in the intake. And I've also been told you can get excessive oil in the intake pipe just from over-filling with oil. One other reason I've heard for oil in the intake side is worn rings that let too much combustion pressure past the piston.
Is any of that true?
I've heard that a bad PCV can let oil end up in the intake. And I've also been told you can get excessive oil in the intake pipe just from over-filling with oil. One other reason I've heard for oil in the intake side is worn rings that let too much combustion pressure past the piston.
Is any of that true?
wmburns
SN Certified Technician
Consider that no seal is perfect. Valves, valve seals, and piston rings all leak at some level. Combustion by products leak past the rings and fill the crank case. If not vented, this would pressurize the crank case blowing valve covers and robbing power. Other very bad things will happen if not vented (water condensation in oil for starters).
These vapors are usually vented through the valve covers. On the Mustang, fresh air goes in the left side, combustion by products are drawn out the right side via the PCV valve.
The crank case vapors are a mixture of oil, unburnt gas, and combustion by products. Normally these are vented via the PCV value and drawn into the intake for burning. The PCV valve ensures that only a vacuum is applied to the crank case. It also prevents any flame (back fire) from passing through it.
Sources of excess oil include missing PVC baffles, worn seals, worn rings, worn/leaky valves. The oil ends up in the intake because as it cools, the oil can condense turning from a vapor back into a liquid. Since the oil is heavy and does not easily evaporate, there it sets in the manifold.
Over filling can cause this. Removing the baffles behind the PCV can also cause excessive oil to be drawn in. A sticky PCV valve is more likely to casue venting problems not excessive oil.
These vapors are usually vented through the valve covers. On the Mustang, fresh air goes in the left side, combustion by products are drawn out the right side via the PCV valve.
The crank case vapors are a mixture of oil, unburnt gas, and combustion by products. Normally these are vented via the PCV value and drawn into the intake for burning. The PCV valve ensures that only a vacuum is applied to the crank case. It also prevents any flame (back fire) from passing through it.
Sources of excess oil include missing PVC baffles, worn seals, worn rings, worn/leaky valves. The oil ends up in the intake because as it cools, the oil can condense turning from a vapor back into a liquid. Since the oil is heavy and does not easily evaporate, there it sets in the manifold.
Over filling can cause this. Removing the baffles behind the PCV can also cause excessive oil to be drawn in. A sticky PCV valve is more likely to casue venting problems not excessive oil.
Big Show 96
New Member
The 96-98's are all known for smoking, but since you did a PI swap it rules that out. The PCV valve is def a problem child for oil in the intake & causing the engine to smoke. My old 96 used about a quart every 500 miles. It smoked at red lights & WOT. The valve guides where worn out. I solved the problem with a complete 2001 engine swap.
I have noticed that there is condensation in the oil cap now. Does this mean I need a pcv valve? And also noticed today that going down a steep grade and letting the engine keep the speed down it started smoking really bad and puffed a little out when I got back in the throttle and cleared up again.
wmburns
SN Certified Technician
Have you removed or altered the stock PCV system? Condensation is not usually a problem on cars with a working PCV system
Some of my cars with go 4000 miles and not use a quart of oil. You can't have it both ways. 500 miles per quart is not steller oil consumption.
Your original question regarded wheither the motor was worn out. IMO, it is obvious that your motor's best days are behind it. Does that mean it is worn out? Maybe. Maybe not.
It is unreasonable to expect a 200k+ mile motor using oil at the rate of 500 per quart not to smoke under certain conditions.
I stand by my original recommendations. If the car runs well. Doesn't foul plugs. Makes good power then drive it.
If you want to know the condition of your motor, perform a compression test and a leak down test. This will tell you the overall health and where it is leaking from.
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