This is a 3.8L V6 with 62,000 miles. I have recently noticed heavy oil consumption in this van. Between oil changes there is a loss of about 2-3 qts in 3000 miles. It has been only 3 months since last oil change with only about 900 miles on the oil. I just checked it yesterday and there was not enough to touch the dipstick. Now everything I am reading on line about this motor says that its normal. This does not sound normal to me. I plan on changing the PCV valve this afternoon. I am wondering if you guys think a PCV valve will cause this much oil lost. I assume the motor is burning it cause I see no evidence of oil leaks on the ground and no excessive oil dripping from under the van. Has anyone seen this before or have anyother ideas to what I can try to resolve this problem.
Thanks Fred
1 qt every 1000 miles is considered by most manufactureres to be normal usage, even in a new car. I’m not suggesting that I’d be happy with that, but that’s considered normal.
Change your PCV valve. A clogged PCV valve can cause excessive oil usage becaus it allows excessive pressure to build in the crankcase. That can push oil through tired old seals.
But I don’t think that’s your problem. I think you’re burning it. I hink the reason you’re burning it is internal wear. I think the reason for the internal wear is that you’re driving most of the engine’s life with very low oil, because you know it’s running low but aren’t checking and topping off the oil between oil changes. While it may not have gone low eneough to lose pressure entirely, it’s clearly run low enough to make it very difficult for the oil to properly do its job.
Oil washes dirt and particulates off of cylinder walls and bearings, removes heat, becomes diluted and contaminated by engine “blowby” (combustion gasses), and is subjected to wear from mechanical stresses. The polymer viscosity modifiers and the molecules “shear”, but I’ll spare you the details. Filthy oil can’t perform in the bearings and cylinders any better than filthy dishwater can wash dishes. So you get severe wear by running constantly low on oil, just like you’d get dirty dishes by washing them in dirty dishwater.
Change the PCV valve, but also start monitoring and topping off your oil. You can try running some Seafoam through the lubrication system and hope that it unsticks some gummed up oil rings (I would), but for the most part the damage is done. Now keep your oil level up and hope you’ll get a few more miles out of this motor.
PS: a compression test is a good idea as it may tell you the condition of the cylinders, but it won’t tell you the condition of the oil rings.
Sincere best.
A PCV could be behind this problem so it’s actually something to be considered as a first step. It’s cheap and easy.
If the PCV is fine then you should make sure there are no leaks by inspecting the bottom of the vehicle rather than look for spots on the ground. Often oil blows back and will stain the bottom of the vehicle while never really marking its spot.
If ok there then this means it’s losing oil past the piston rings or valve seals; or both.
Any overheating episodes in past, irregular oil changes leading to oil sludging or coking could cause a problem like this.
I’m aware that many claim a quart per 1000 miles is normal but in my opinion it means there’s a premature problem.
A compressoin and/or leakdown test, while not 100& definitive, is the next option for checking piston rings. Ideally, the compression readings should be in the 185-190 range.
There is no test for valve seals as those are a replace and pray thing. Odds are the valve seals are not the cause unless the engine has been overheated in the past. Hope that helps.
Thanks guys for the input. Now a little extra information. I have always used mobil-1 full synthetic oils in all my cars. I have read that in this case I might be better off using regular oils cause the full syn mobil1 is too slippery. Kinda makes a little since but I don’t know if I want to change.
I have also read that I should pull the front 3 plugs and inspect them for evidence of biting oil. I have read in some forums that there also might be a problem with no deflector in the valve cover allowing the oil to just be sucked up the PCV valve. They mentioned that when the intake plentom was removed there were pockets of oil laying in the valleys of the intake.
What is your take on this?
Thanks Fred
What weight (viscosity) of oil are you using? many oils change places now have 5W20 and 0W20. If they are using wither in your engine, expect higher oil consumption. Anything lighter than 5W30 will cause more oil to be consumed in your type of engine.
I am using 5w-20 as per the owners manual. I have also herd of installing a oil catch of some sort on the PCV hose?
If you switch to 5W30 you will use less oil. The 5W20 is mainly a move to meet the CAFE mileage standards dictated by the Federal government.
Having said that, at that mileage a well maintained car should not use much oil; maybe 1 quart per 3000-4000 miles. As others mention, have the car gone over to see if there is an inexpenive fix.
Please also note that using synthetic oil from day one in some engines will not seat the rings properly and the vehicle will use oil for all its life.
[b]Docnick, Please Refer Me To Information On The Topic That You Mentioned (See Below). Could You Give Me Some Links, Please ?[/b]
“Pleas[e] also note that using synthetic oil from day one in some engines will not seat the rings properly and the vehicle will use oil for all its life.”
Should I ever repeat this to anybody I don’t want them to think I’m just making things up or starting and spreading rumors or old wives tales. I need to verify the sources.
Thanks,
CSA
Ok guys here is some more updates. I just removed the PCV valve and hose and it was coated in oil. The hose it self was dripping with oil aswell. I also pulled the front 3 spark plugs to inspect for burning oil. All 3 plugs were clean without any sign of oil deposits or carboned up with deposits. They were light gray to white on the insulator.
I also had an EGR code with the check engine light and yesterday removed the EGR valve to inspect and clean. The tube that comes of the EGR to the intake and inspected down into the intake with a flashlight and noticed pools of oil laying down in the bottom of the intake.
To make a long story short. I replaced the PCV and EGR and marked the dipstick to were the level is and I will keep an eye on it to see if the level still drops. Thanks for your input in the earlier posts and would love to hear some input on the pools of oil in the intake.
Thanks
The Information That I Have Quoted Below Scares Me A Bit.
“I have recently noticed heavy oil consumption in this van. Between oil changes there is a loss of about 2-3 qts in 3000 miles. It has been only 3 months since last oil change with only about 900 miles on the oil. I just checked it yesterday and there was not enough to touch the dipstick” __________________________________________________________________________________________
My wife’s high miles car uses considerable oil and she drives 700 miles / week. However, knowing that it uses oil, I check and top-off (less than 1/2 quart) every week-end without fail, come heck or high water. I’ve never, ever pulled a dipstick on any car I’ve had to find that the oil doesn’t register ! To me, things are out of control at that moment.
Knowing that a car consumes oil and then hesitating to check the level frequently leads me to be concerned that this vehicle was allowed to get too low on oil at some point and has suffered internal damage.
Mobil-1 is terrific and very high in quality, I use it, but not as good as the world’s cheapest oil if the quantity was not always sufficient. This could be a case of closing the barn door after the horse gets away.
I’m afraid that what may have started as minor ( PCV Valve, Oil Baffle, “normal” consumption, etc.) , manageable problem has escalated into something more ominous.
This is why I check our entire “fleet” of family vehicles every week-end, even the new ones. It takes me less than 10 minutes to do the four cars currently on the road, including topping-off w/washer juice. This is how a car owner becomes aware of any potential fluid consumption / leaks problems early on and not after the fact.
CSA
CSA
Notice the fact that I said “recently I noticed”. This van has never in it’s life burned or consumed oil. Until now every 3k miles I changed the oil and it was right where it was suppose to be. It wasn’t until recently I noticed it was low. So this oil consumption deal is only something that has happened in the last 3 months. That is what is leading me to a PCV valve. Oil control ring just dint go bad and starting letting oil by unless there is something else is causing them to gum up such as low oil.
I know that no oil is bad and that is why I am here talking about possible fixes with you guys. This car has only been low only one time and that as the last oil change. So again thanks for you input on the matter. I will post again and let you guys know what I found.
Thanks
Fred