Will broken PCV hose coming off the valve cover cause oil light to flicker at idle?

[waynefoutz]

Will broken PCV hose coming off the valve cover cause oil light to flicker at idle?

24V DOHC with 160,000 miles on it.

I drove home from work tonight, a 28 mile drive on the highway, and as I stopped at the first traffic light, I noticed the light flickering, and simultaneously, I got a big whiff of oil. I pulled over, pulled the dipstick, oil level was fine. I also noticed there was oil on the outer corners of my hood near the windshield, on both sides. The underside of the hood seemed dry. No leaks underneath. So I started poking around at the PCV hoses, and sure enough, the elbow is broken at the rear valve cover. Would this cause the oil light to flicker or am I grasping at straws?

The car runs fine, no knocks or pings.

[Breeves002]

It shouldn't cause the oil light to flicker. Although I would get the PVC elbow replaced ASAP. Go ahead and do an oil and filter change and see if that helps. Wondering where that oil came from.


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[sousa632]

The 99 Duratec has a PCV valve on the rear 'cam cover'? My 01's PCV is in the center of the motor under the UIM.

[sheila]

John, Wayne's pcv valve and hose is directly under the throttle body. He may be referring to a crankcase vent hose?

[waynefoutz]

Originally Posted by sheila

John, Wayne's pcv valve and hose is directly under the throttle body. He may be referring to a crankcase vent hose?

The hose runs from the air cleaner "accordion" to the center top of the rear valve cover. The rubber elbow is snapped. I don't think it's been that way long, I just replaced the windshield washer hose a few days ago and didn't see any other broken hoses, heck I might have inadvertently broke it then.

All I do know is that I'm stumped. When the light came on, I got a heavy whiff of hot oil, but I can't find anything wet, other than the one corner of the hood. I just went back out again after it sat an hour, started it up,no oil light. Shut it off, checked the oil, the level was fine. Crawled underneath, other than the normal grime, I didn't see anything fresh. Took off with it, got it back up to normal temperature, pulled in the driveway, let it idle, no oil light. As of now, it's purring like a kitten, even with the broken hose.

[sheila]

Wayne, you can replace that broken elbow with 1 from the Help! section at most parts stores. Might check the integrity of the u-shaped pcv hose directly under the throttle body also. A known maintenance item on gen3 tecs.

[waynefoutz]

I replaced all the ventilation hoses, had the oil changed with 10w30, and drove it the first day, all seemed well. The next day I drove the 34 miles to work, and the oil light came back, flickering at idle. 2 days later (I am a truck driver, so the car sits for days at a time while I'm on the road,) I pulled the dipstick, oil was full, so I drove it back home, in stop and go traffic no less, and no oil light. ran like a champ. The next morning, I drove back to work, when I exited the highway, breathed a sigh of relief, no oil light. Pulled into the employee parking lot a few blocks away, and dammit, there it was, flickering again, taunting me.

This car makes no unusual noises, it runs like a top. I bought it 8 months ago, put $1200 worth of brake and chassis work into it, and the oil was black as coal. I've had the oil changed 3 times with 5w20, the odometer is 160,000, it was at 154000 when I bought it. there is an oil leak on the bottom half of the motor, nothing substantial, I add maybe half a quart every 2 weeks.

what's my next step from here?

[WJC]

Originally Posted by waynefoutz

what's my next step from here?

First, the engine should idle at around 750. If you have a driveability concern caused by a low idle due to the PCV elbow under the throttle body, your oil light can come on.

Once you eliminate driveability problems, your common oil leak areas on that motor are: oil pan gasket, valve covers, and oil pressure sending unit. Clean the pan area and re-check the source of the leaks, making sure it's just the pan gasket and not crank seals. The pan gasket is basically a 100% failure rate and very difficult to replace, although there are some shortcuts. Good luck.

[behlinla]

^+1 Low idle or a bad pressure switch is a common cause of the flickering oil light.

I will also add that you might considering putting a better quality filter on. If you have your oil changed at a shop (like JiffyLube) you're going to have a dirt cheap oil filter on your car that might be causing too much of a pressure drop.

[pawpaw]

Originally Posted by waynefoutz

I replaced all the ventilation hoses, had the oil changed with 10w30, and drove it the first day, all seemed well. The next day I drove the 34 miles to work, and the oil light came back, flickering at idle. 2 days later (I am a truck driver, so the car sits for days at a time while I'm on the road,) I pulled the dipstick, oil was full, so I drove it back home, in stop and go traffic no less, and no oil light. ran like a champ. The next morning, I drove back to work, when I exited the highway, breathed a sigh of relief, no oil light. Pulled into the employee parking lot a few blocks away, and dammit, there it was, flickering again, taunting me.

This car makes no unusual noises, it runs like a top. I bought it 8 months ago, put $1200 worth of brake and chassis work into it, and the oil was black as coal. I've had the oil changed 3 times with 5w20, the odometer is 160,000, it was at 154000 when I bought it. there is an oil leak on the bottom half of the motor, nothing substantial, I add maybe half a quart every 2 weeks.

what's my next step from here?

Above you've posted that you had the oil changed with 10w-30 & your engine is specified to use 5w-20. You seem to be located in the north east, so this time of year thats cold country & your engines top end cams sure would appreciate a 5W lube, so that it gets some right away after a cold start.

If the engine is sludged up some, such that the top end oil returns are clogged up & holding more oil than they should, or the thicker than specified 30wt might be taking longer to drain back to the oil sump, causing it to run low after a highway run because a lot of it is still in the top end. If the top end is holding more oil than it should, that oil can be whipped into a froth/areated by the cams & that, along with a slow drainback to the crankcase, can cause the sump to run low & if the oil returning to the sump is areated, the oil pump sure won't like trying to pressurize it. So, make sure your using the specified viscosity & service grade crankcase lube.

If you used other than the specified Motorcraft oil filter, put that on your flickering oil light suspect list too, as I've also had other oil filters cause a flickering oil light at idle, or start up rattle.

More thoughts for consideration, let us know how it goes.