2007 4.2L PCV
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Fleet Mechanic
Joined: Jan 2007
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Thanks. I need to check/replace it because I'm getting a little oil film on the rocker covers and it might be from a build-up in crankcase pressure. It only has 30,000 on it and basically is still like new. I did have to replace the crummy Ford battery after only 13 years. 
Oil has been changed every 2000-3000 miles (yearly) and only Motorcraft 5W-20 and Motorcraft filter has been used.
Oil has been changed every 2000-3000 miles (yearly) and only Motorcraft 5W-20 and Motorcraft filter has been used.
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Fleet Mechanic
Joined: Jan 2007
Posts: 1,293
Likes: 18
Wait; 'heated' Positive Crankcase Ventilation valves?
Okay, if they are, I know why - to thaw the valve in cold weather so it can work. I ran into this problem on a Saturn VUE I had. It was in the body shop for minor repair, and it was a cold January. They would bring it into the shop, then drive it out. They must have done this a few times and moisture built up and froze in a hose that had a low spot the way it was routed. I picked up the car and drove it away without realizing this, and it blew an oil leak in the rear cam cover.
Okay, if they are, I know why - to thaw the valve in cold weather so it can work. I ran into this problem on a Saturn VUE I had. It was in the body shop for minor repair, and it was a cold January. They would bring it into the shop, then drive it out. They must have done this a few times and moisture built up and froze in a hose that had a low spot the way it was routed. I picked up the car and drove it away without realizing this, and it blew an oil leak in the rear cam cover.
Cargo Master
Joined: Jul 2009
Posts: 2,538
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From: Des Moines
Wait; 'heated' Positive Crankcase Ventilation valves?
Okay, if they are, I know why - to thaw the valve in cold weather so it can work. I ran into this problem on a Saturn VUE I had. It was in the body shop for minor repair, and it was a cold January. They would bring it into the shop, then drive it out. They must have done this a few times and moisture built up and froze in a hose that had a low spot the way it was routed. I picked up the car and drove it away without realizing this, and it blew an oil leak in the rear cam cover.
Okay, if they are, I know why - to thaw the valve in cold weather so it can work. I ran into this problem on a Saturn VUE I had. It was in the body shop for minor repair, and it was a cold January. They would bring it into the shop, then drive it out. They must have done this a few times and moisture built up and froze in a hose that had a low spot the way it was routed. I picked up the car and drove it away without realizing this, and it blew an oil leak in the rear cam cover.
I think the coolant heated ones were intended to keep the valve hot after shut down to allow moisture to drain out of the valve/hose - there’s a maze of 1/4” coolant lines running from the intake to the valve to a fitting on the throttle body and back to the intake.
Also, you can test PCV operation by checking for vacuum at the oil dipstick tube. At operating temp at idle, vacuum should be 0-2 in*Hg. Ideally it’s less than 1 because it should be maintaining a balance between crankcase pressure and engine vacuum. Higher than 2” indicates a valve that’s sticking too far open at idle or a plugged breather filter (if equipped).
No vacuum (or positive pressure which can be read with a dual gauge if you have one) indicates restrictions which could be a plugged/partially plugged valve or baffle inside the valve cover, or collapsing hose.
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Fleet Mechanic
Joined: Jan 2007
Posts: 1,293
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Yep - that’s basically it. I can’t recall all the details, but there’s 2 types of electrically heated valves - one that’s switch activated at or below 40*F and one that’s PCM controlled at or below 32*F.
I think the coolant heated ones were intended to keep the valve hot after shut down to allow moisture to drain out of the valve/hose - there’s a maze of 1/4” coolant lines running from the intake to the valve to a fitting on the throttle body and back to the intake.
Also, you can test PCV operation by checking for vacuum at the oil dipstick tube. At operating temp at idle, vacuum should be 0-2 in*Hg. Ideally it’s less than 1 because it should be maintaining a balance between crankcase pressure and engine vacuum. Higher than 2” indicates a valve that’s sticking too far open at idle or a plugged breather filter (if equipped).
No vacuum (or positive pressure which can be read with a dual gauge if you have one) indicates restrictions which could be a plugged/partially plugged valve or baffle inside the valve cover, or collapsing hose.
I think the coolant heated ones were intended to keep the valve hot after shut down to allow moisture to drain out of the valve/hose - there’s a maze of 1/4” coolant lines running from the intake to the valve to a fitting on the throttle body and back to the intake.
Also, you can test PCV operation by checking for vacuum at the oil dipstick tube. At operating temp at idle, vacuum should be 0-2 in*Hg. Ideally it’s less than 1 because it should be maintaining a balance between crankcase pressure and engine vacuum. Higher than 2” indicates a valve that’s sticking too far open at idle or a plugged breather filter (if equipped).
No vacuum (or positive pressure which can be read with a dual gauge if you have one) indicates restrictions which could be a plugged/partially plugged valve or baffle inside the valve cover, or collapsing hose.
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