May need to be moved to different forum, but I have a technical question I'd like to touch up on. I had responded to a dead thread, and thought it would be best to post a new thread, since my reply was a bit out-of-date. Anyhow, here's my post.


My 05 revup is seeming to have an oil consumption issue. 156K on the clock, usually burnt around 1 quart every oil change 15000 miles ago, (normal) until progressively getting worse around 15,000 miles ago, and now its burning more, around 1.5 quarts per 1000 miles with baby driving. 95% my miles on the car have been at cruise control at 58 mph. (no reason to lie to you all here) That said, for S and G's, I drove the car moderately harder, with a few pulls and average highway speed cruising around 70-80 for 1000 miles to test consumption... My oil consumption was the same. Havent done compression check but my car runs tip top, starts perfectly fine, no smoke, and when crusing 60 mph, I'm getting over 30 mpg's. (31 indicated to be exact, Just a month ago I ran over 500 miles on a FULL tank with two stops for RR) I'm praying its just a bad PCV valve; I bought one over the weekend and am going to install it next weekend. I am convinced it is that, because I cant get myself to think it's the rings. Not only that, this may sound odd, but I swear my PCV valve makes a weird "TSSSSSSSSSSS" hissing noise after driving. I'm thinking the ball valve in the PCV valve is sticking or something. I always check oil levels, and the car has had nothing but SynPower 5W-30 at 3,000 miles or less for over 60K miles. (Since I began owning it 7 years ago.) I've looked up symptoms of bad PCV valves, and usually they'll start causing vacuum issues or fouled plugs, but I haven't had that. I'm praying it's just half failing and my rings aren't shot. Any idea about my theory?

 

Sman, when you remove the PCV valve shake it, if it rattles that's not what's causing your OC! Those valves never need replacing, give them a shot of carb cleaner (every garage needs a can if you work on cars) and give it a good shake...now it's like new! Hissing sound could be several things, if it's not your radiator look for a broken rubber vacume line.
Gary

 

unfortunately, I've traced it down to the PCV valve... It's not a vaccum leak. I know about those from other cars.

The part was only 17 dollars; I figure why not completely eliminate the potential risk. Not only that, If it only sometimes siezes to close/open, who knows if it decides to cooperate when i she the ole girl!

I'm intrigued to see if other people think this could be the pcv valve... Is it possible its just being temperamental and sticking occasionally? Do you have to have other symptoms besides just oil consumption? If not pcv valve, and "assuming" not rings... What could be other sources of Oil consumption with no visible leaks, or drips, or symptoms?


Thanks to all!

 

Pull out your plugs and see if there is any oil getting in there (My #5 was leaking). There are also PCV passageways in the valve cover that can cause OC from what I've read. I don't know of a way to clean them other than replacing the cover. But, that's even if that is what your problem is.

Did you check the usual spots for oil leaks as well?

Try a compression test dry/wet that will tell you if it's your rings.

 

Sadly there's a 99.127% chance it's your rings so just get ready for that inevitability, especially since you drive a rev-up with over 150K miles. You have lots of choices: rebuild the motor, keep adding oil but know the motor will eventually fail, buy a new motor or buy a new car. That is our reality like it or not.

My 05 non-revup burns a quart every 1500 miles with 137K on the clock and that's with a new PCV valve every 30K and a catch can.

 

Blue is correct, it's definitely your rings. There's no way the PCV can have that big of an effect on oil consumption. Good news tho, is that your car is just as happy to burn oil as it is gasoline, so you aren't really doing any damage or losing much of anything as long as you keep it topped off. It's really just annoying to constantly be topping it off, but that's pretty much the worst of it.

You can slow it a bit by adding a catch can too.

 

Just took the PCV valve off, it had no play in it, with no noise when shaking. It also had oil in it, which is a negligible sighting, as I expect some to be in it regardless, because some oil vapor is to be expected. I expected to burn around a quart per oil change, which is acceptable with these motors; however, it increased to 2 quarts, maybe three, between 3k intervals. I've heard of them doing worse with just a bad PCV, so I'm praying that its still that. Comparing the old to new PCV valve, The old one looks further pressed up into the housing, which kinda confirms my assumption that it it's stuck open. Stuck open = more apt to allow oil to pass by.I took a video of the two PCV valves, and me shaking them. It's clearly audible between the two.

 

Now that the PCV issue is solved all you need to do is drive your G, checking your oil level closely/frequently to see if you've slowed down the OC!
Good Luck & enjoy the ride...Gary

 

I'm around 500 miles into the oil change, I've been so anxious to check the oil I couldn't wait to see how it has been holding up. Popped the oil stick out after a hour cooldown of motor and oil is still all the way full! None has gone down!

As a note, I've tried driving the car very conservatively. Highway speeds have been 75 or under, no engine breaking, and I've allowed a decent amount of warmup time, (2-4 minutes depending on temps) to let things get flowing. Obviously oil isn't operating temps, but you get my drift. I haven't driven the car spiritedly in the last 500 miles. I'm going to keep driving her nicely, and take things slow for some time. I'll update again at 1,000 miles.

 

Glad you didn't break your motor lolol and please keep us updated.

 

I gotta quit using the forums on my iPhone. Autocorrect gets me in too much trouble.

 

just checked my oil at home 1,000 in. My dipstick is reading a little more than 3/4's full on the dipstick. Compared to burning 3 quarters per 3,000, I am loosing substantially less oil. With the dipstick reading a bit above 3/4's full, would you assume that's about normal? That puts me a bit shy of a quart lost at 3,000 miles. (Ps. Car just hit 156,000 as we speak)

 

That's not bad Sman, with what your G has on it's clock a quart every oil change is acceptable! Even Nissan might agree. I recommend adding oil, so your dipstick shows full to the line all the time!
Gary