Vanishing Oil, need advice

[miasma]

Hey, I just posted this in the additive forum too, but I figured people here might be able to help too: Hey all. I have a '95 nissan maxima. I drive it fairly hard and it has quite a few performance modifications. I take it to the local drag strip once a month or so in the summer. Also, if it matters, I live in Boulder, CO at over a mile high. I am losing about a quart of oil a month. These are tough driving conditions, where about half my trips are just over a mile long, barely enough time to even get the engine warm. While I dont pound on the engine when it is cold, I do go to WOT quite often. Basically, I am guessing that right now, I drive about 700-900 miles a month. I just put a quart in yesterday and reset my trip meter so i get a better idea. I had been using mobil 1 5w30 over the winter and 10w30 mobil 1 now, both sypersyn. I have been using synthethic for about a year and have about 88,000 miles on the car. I used B&G 3 step engine cleaning at the beginning of this year (throttle body spray, fuel additive and vacuum system intake cleaner). I also used protec oil additive before the oil change. I have not done any blackstone analysis since I dont feel the oil has enough time before adding fresh oil, to give accurate results. I have good, even compression. I passed emissions easily about 2 months ago. I have no dripping of any sort. I have no blue smoke, ever, that I can tell. I do get a slight 'backfireish' pop in the morning when I start the car, but never any other time in the day. I attribute that to my wideopen exhaust that does not baffle those sounds like the stock exhaust did. I am guessing that the problem is with valve stem seals, but am not sure. I can not afford to get those replaced, and am certainly not mechanically inclined enough to do headwork on my own. Do you think auto-rx is worth a shot here? If so, how would I do the application? The engine cleaning way, or the leak way? Or another way? Is there another prognosis than valve stem seals? What about the slight pop at cold start? Thanks!

 

[RussellA]

Just a long shot, but I would make sure the PCV system isn't clogged. This can cause leaks, and sometimes this goes undetected because it leaks only when the car has built up crankcase pressure(i.e. only while you're driving). Lot's of other things it could be, but I would check it just to rule it out.

 

[Chris B.]

Sorry to change the subject but where do you take your car to race? I would like to find a track and I live close to Ft.Collins. Boulder is not far at all. How much do they charge to run your car? What #'s is your Maxima doing? Thanks and have fun and enjoy the sight!

 

[nick778]

In addition to the PCV you might also want to check the EGR fitting into the intake manifold. It is a small hole/fitting into the intake manifold and is very prone to becoming clogged with carbon; the larger tube is ususally ok. You can remove it (not easy as there is not a lot of room to work) to clean everything out. Among other things, it can produce the type of symptoms you are describing.

 

[miasma]

my pcv valve is new and in good conditon. another thing is that i just changed plugs not too long ago and the old plugs were not fouled at all. interesting thing is that i just got a CEL for EGR Flow High\Low. i reset the computer and it has not come back on again. i think the vacuum line into the manifold and egr valve could very likely be clogged. would that really cause oil consumption though? what symptoms would a clogged egr cause? backfire pop from too much egr flow at idle? oil consumption??? what? i thought egr was only to reduce emissions and lower combustion chamber temps. as far as racing, i race at bandimere. havent been there yet this summer, but i should be running low 16's high 15's there which would equate to low to mid 14's at sea level.

 

[MolaKule]

If the EGR is malfunctioning, this could lead to higher combustion chamber temps and higher oil volatility. Any smoking on startup or deceleration? Valve stem seals OK? You might want to try Redline 10W30. I have had zero consumption with Redline so far, whereas with M1, I had to replace about 4 oz. every 1.8 K.

 

[miasma]

no smoking except maybe a LITTLE on startup, white smoke from water in the exhaust, but thats it. i do sometimes hear popping sounds during engine deceleration but never any smoke, again, i just attribute that to the wide open exhaust. how do i test the valve seals?

 

[nick778]

Any fault with the EGR in the Maxima isn't usally the rubber vacuum line. It is ussally due to a sticking valve (which most times can be cleaned) or the small pipe between the intake manifold and valve (or exhaust manifold...I forget exactly which but it is not the large one) gets clogged both inside and where it enters the intake manifold. There is a very good write-up on Maxima.org on how to R&R this whole system. Do a search under 4th Generation forum and use 'EGR' as a search. The post is about 4 pages long. In any event, I would suggest at least cleaning the system and valve where you can and you can also test the valve. Other symtoms of something wrong with the system include intermitent rough or eratic idle and backfiring is possible along with the previous mentioned increased combustion temps.

 

[Chris Jefferson]

I believe if your EGR system was or is similar to the 95' 240sx's,you should also check the diaphram and see if it is easily movable up and down by hand. if not, then it may be malfunctioning. As for oil, id switch over to Mobil1 0w-40. This is not directed at anyone!! But, if we Americans (that includes you Canadians too as you are in North AMERICA) would quit believing that we "have" to run a 5w-30 or 10w-30 oil because the car co. want us to for CAFE reasons and also quit buying into the oil co.'s rhetoric that simply exists to prevent them from being sued by the car manufactuers, wed be better off. What i mean is, we are the only continent in the world (that i know of to use and advocate it as well to others) that uses 10w-30 and 5w-30 oils and change it every 3K miles and think that using an xW-40 oil will somehow hurt the engine because it was designed for an xW-30 oil, which is bogus. If any of you Japanese car owners were to get a look at the japanese spec manual for your car and its engine, or even a Euro spec manual, you would see that almost always a xW-40 viscosity oil is spec'd out for use. But for us to use that thick of an oil would hurt fuel mileage and thus they go one grade down (now two) to get good fuel mileage. Guess what im trying to say is, for goodness sake's, please dont worry about trying a xW-40 oil as it wont hurt your engine(s). Especially if its a low xW-40 oil (ie. its cst @ 100C is like 13.8 like AGIP's Extra HTS 5w-40 syn. oil). Course, you can always mix 50% 0w-40 (or a 5w-40) and 50% of an xW-30 and end up w/ a heavier xW-30 oil. Anyways, sorry for the rant its late and im tired. been out looking at new homes all day. cheers to everyone, chris j.

 

[miasma]

ok, i guess i will get to the egr system. i visit the maxima.org forums many times daily, and as a donating member can still search . I will let you guys know what i find. thanks for your help.