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So I have a recently acquired 2000 Dodge Durango with the 4.7 liter engine. It has 148k miles, runs very smooth, the oil is very clean at the end of the oil change interval, and is not losing any coolant. It is losing oil, but it has no leaks, and is not blowing smoke out the tailpipe. I discovered that it was blowing the oil into the air filter through the PCV line. Upon further investigation, the PCV lines were filled with gooey oil and condensation. I pulled all of the PCV lines, and PCV valve off to clean or replace them, and noticed that the vacuum side of the PCV system wasn’t connected. It is on the back if the intake manifold, so you can’t see it at a glance. My question is, should I pull a valve cover to make sure there isn’t any of the goo under there? I’ve read that it is a common problem with this engine to have condensation and oil goo in the PCV system, usually from a clogged PCV valve. I also read that it is a common problem on any engine for it to consume oil because of a clogged PCV valve. I found a Dodge TSB about re-routing the PCV system to prevent build-up in the lines, it gets rid of any low spots where oil and condensation can accumulate. I bought new PCV lines, and a new PCV valve. I am going to clean the PCV system really well, and hope for the best. My worries are that that gunk made its way under the valve covers. Should I spend the time and investigate, or should I just replace the PCV system lines and valve, and see if it continues to lose oil? Thank you in advance.
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Like you say, those engines are known for forming sludge. The vehicle is new to you and you probably don’t have a good idea how often the previous owners changed the oil.
If it were my vehicle, I’d pull the valve covers for cleaning. Also, I’d drop the oil pan and check to make sure the screen on the oil pump pickup isn’t wearing any sludge either. With a “new” used vehicle, the biggest favor you can do for yourself is to look for and remove as many traces of the previous owners’ bad habits as possible.
Regular (and frequent) oil and filter changes on an engine with this kind of reputation would be good preventative maintenance.
I went ahead and replaced all of the PCV lines, as well as the PCV valve. I also cleaned out the oil filler, where the PCV valve is clipped into. I let it run for 30-40 minutes, and it was not blowing smoke into the air box anymore. I don’t have time to pull a valve cover today. I think that in the interest of saving time, I’m going to drop a bore scope into the PCV vent on the valve cover, and see what I can see before I go tearing into it. They really shoehorned that motor in there. I’d have to have the AC evacuated to remove the passenger side valve cover, though the driver side would be easy to take off. Another thing, to remove the oil pan in this truck, you have to drop the front differential, which is also ALOT of work. So I can also put a bore scope up into the pan when I have the oil drained. The previous owner kept pretty good records of maintenance that I found in the glove box. Every service was documented up until 124k miles, but there was no mention of servicing the PCV system. So there is only 24k of maintenance that is not accounted for. I have a feeling that its not going to be bad under the valve cover, just because the oil is so clean at at the end of a 4000 mile oil change, and it has very good oil pressure. In the event that I do find sludge under there, how could I go about cleaning it? Is there a solvent that I can use that will be safe with rubber valve seals? Since toward the end of my oil change interval, I think I’m going to put seafoam in the oil for 100 miles or so before I drain it, and see what comes out, it couldn’t hurt.
[quote=”mikeywil0003″ post=140612]In the event that I do find sludge under there, how could I go about cleaning it? Is there a solvent that I can use that will be safe with rubber valve seals?[/quote]
Use 1 quart of auto trans fluid with 3-4 quarts (depending on how much your crankcase holds) with 10W-30 motor oil for the next 2-3 oil changes.
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