ardika

iTrader: (3)

For Oil Gods on this board (Yes Bill, that will include you too):

I have noticed that my oil/oil filter condition *could* be assessed from my mpg consumption. That is, where my mpg starts dropping (2-3mpg drop from the "usual" mpg) I would need to change my oil and/or oil filter. You could say it could drop as much as 5 mpg, but I was referring to the 2-3mpg as the "time to change it".

FYI, I drive about 80% highway and 20% city, no ECU codes, running Amsoil 0w30 in the past 20k miles, current mileage 131k, no oil consumption, using either 93 (95% of the time) grade or 89 (5%).

I usually get around 30mpg on a level highway (no significant uphills), cruising at 74 mph. City driving is definitely worse (drove around in NYC only get me 20 mpg ), but combined mpg usually averages around 26-28 mpg (city and highway). Car is equipped with Stillen intake and Frankencar intake with grounding cables (I forgot which brand).

Case in point:
At 107,000 I noticed that my Castrol Syntec 5w30 was black and the best mpg on the highway is "only" 25 mpg. City driving in Madison/Milwaukee, WI only gets me around 20 mpg. Oil was used from around 100,500 miles. Changed oil, mpg goes back to normal.

I have been using Nissan oil filter/Amsoil 0w30 since 110k, brand new oil put in at 125k, put in the Superplug (magnetic drain plug) w/filter change every 5k. This time, I changed the oil filter at 131,265 and just before this, I could see that my mpg took a dip to high 26 mpg on the highway and "only" 24 in the city. Put in brand new filter, put Techron and 89 gas (to clear out carbon deposits) and mpg goes back up to normal. The old filter has been used for 6,265 miles and clearly this is really close to the limit of Nissan filters.

I will wait until 135k and put brand new oil and Amsoil filter. When I do this, I will wait till 10k to change the filter to another Amsoil filter and drain the whole oil after 20k of usage (that would be at 155k!).

What do you think guys? Oil and mpg? Oil filter and mpg? I believe there is a strong correlation between those two, but I could not see them reflected on the Bill's spreadsheet.

FYI, based on the color of my Amsoil 0w30, 6,265 miles is definitely "piece of cake". It still shows very clear color, caramel-brown color. I remember when I was taking out that Castrol Syntec at 107,000 miles, it was black.

Colonel

But color has nothing really to do with oil ability to lubricate efficiently.

I personally have a 01 and track everything for mileage and have not noticed a correlation between the two. But then again my baby only has 24K on it. A mere pup in the age of the VQ!

ardika

iTrader: (3)

Colonel,

I agree with you. Without full analysis, oil ability to lubricate can not be judged.

I am trying to get a "ballpark" using mpg for my guidance. This might be applicable since I drive all the same roads (I-94 stretch between Madison-Milwaukee) and therefore I could notive a dip on the mpg by 3 or 4 when I come back from this stretch that *might* be attributed to oil condition.

Eric L.

MPG depends on a number of conditions, and its difficult to tell by oil changes alone. For example, just five or ten minutes of stop and go traffic can kill mileage by several miles per gallon. For your info, I get around 16-17mpg in the city, and around 25 on the highway (your 30mpg is fantastic). I do notice that after oil changes, my mileage also increases. But whenever i change my oil I also do little things like check my tire inflation, clean my intake, etc...so i think the combination of everything contributes to the mpg increase, not mainly due to the oil change alone.

It is also true that the color of the oil has nothing to do with its ability to lubricate and protect the engine. The general consensus on this board is that unless you drive like a maniac, 5000 mile intervals are acceptable for conventional motor oil, 7500+ for synthetics like mobil one. As for the super conventionals, like Amsoil, its your car, you can put whatever you want into it. There has been no proof as of yet that long change intervals with amsoil harms the engine.

ardika

iTrader: (3)

Eric, you mean Super Synthetics there?



I could see that Amsoil is slowly cleaning up the inside of my valve cover. I remember my first batch of Amsoil is darker than this one at 5k (put in at 110k, change filter at 115k). This batch is definitely hold much better in terms of color change.

I believe Bill would be interested in getting my oil analysis for this batch (will drain it out at 135k) and then the subsequent analysis (20k intervals with 10k oil filter change).

Hmm...

Frank Fontaine

I agree with you, because I've got about 5500 on my Kendall GT3 and on a 470 mile trip, I cleared 28 mpg at the highway points. The car is a 98 SE 5-spd with service engine soon lamp on and 75000 miles. There were some 85 mph bursts on the NJ TPK as well so who knows, maybe I coulda done better. On such an old car I think 28 is not bad. When not on the highway or with little 6 mi highway 8 mi city commutes I avg about 20.

From my own experience a clean air filter seems to be able to make a multi-mpg difference. I once avgd 24 on a long highway trip and when I put in a new air filter and did the same trip 2 wks later, it went to 30. Sounds unbelievable but I did experience it when the car was about 1 year old.

bill99gxe

iTrader: (1)

In looking at analyses, I've noticed no correlation between oil consumption and fuel economy. My 99 has consistently had relatively low MPG (20 to 21), and around 25 for highway driving, especially considering the grandma driving it sees. Haven't used a drop of oil since the < 10k mark.



Based on your descriptions, your correlations could stem from viscosity increasing over an oil interval and the MPG going down because of extending oil intervals. You have to be fairly careful with that, as my 2 oil changes in 2 years on both cars has resulted in an unexpected spike in viscosity, although I haven't noticed a fuel economy change myself.

I would take a sample currently and then go 5k on subsequent intervals using the Series 2000 synthetic at least 2 or 3 times.

iwannabmw

iTrader: (3)

Interesting theory. I haven't noticed any correlation between drain intervals and fuel mileage myself. There's probably too many variable that affect mpg to accurately be able to gauge when it's tie to change the oil based on that alone.

ardika

iTrader: (3)

Mark, Bill and Frank:

I drive around 30k miles per year, and my eyes are constantly looking at the gas gauge at least 10 times whenever I drive my car (even for a 2-mile trip).

If you were with me, you guys could see my sadness whenever I took the off ramp (which means city driving!). .

I bought the car at 89k, change the oil and fluids completely at that time. It's using conventional oil up to 100k. After that, it went through 3 oil changes with Castrol Syntec and FRAM (!) filters up to 115k (my previous post were incorrect). At 115k (instead of 110k), I got my first batch of Amsoil 0w30 with Nissan oil filter. Timing chain sound was heard about 4 days after changing the oil. It was gone after 3 starts. September comes, at 120k, change the filter. Took a trip to NYC, and at 125k, change the oil completely.

This first batch of Amsoil was used "only" 10k with Nissan filter every 5k. The second batch, that was put in 125k is still being used. No abnormalies detected until recently I could see the gas gauge falls pretty rapidly (I know using the Nissan filter beyond 6k is pushing it). Change the filter recently at 131k, everything goes back to normal (you know, the gas gauge).

bill99gxe

iTrader: (1)

Interesting indeed.


Damn you put some miles on a car.


Looks like a classic chicken or the egg scenario....is it the filter or the oil? If indeed the MPG is increasing after the sole move of changing the filter, then the filter is "clogging" up after 5k or so and restricting flow to some extent, causing your lubrication system to not as effectively keep the engine running at top efficiency. That *could* decrease your mileage.

Taking a sample and looking at the viscosity value and the insolubles value would better pinpoint the "weak link" in your current drain interval habits.

ardika

iTrader: (3)

Bill,

When I saw the Castrol Syntec at 7k, I know for sure that it was pushing it (especially with FRAM filter).

With current batch (Amsoil and Nissan filter), I believe it's the filter since everything will go back fine after changing the filter (and adding, like, .2 quart?).

I am ordering my next batch of Amsoil from iwannabmw today and I did order one SDF 13 and another SDF 20 (per your recommendation - I quote Mark for that). My plan is to extend the drain up to 10k (well, probably at 8k for a start and then 10 k after that).

I will need to order a sample kit. How do I place the order, Bill? Is it through you? Let me know on this one.

I will be at Jeff's place in LI sometime soon, I will ask him to drain the oil a little bit (I still have a quart laying around here). I simply don't have time right these days due to my work schedule to drain the oil (I know it's very simple, but my setup time is definitely longer than the actual activity of taking the sample).

How much do we need for a sample anyways? Half a quart maybe?

SR20DEN

iTrader: (7)

Does anyone else but me get annoyed when someone asks a question that could be related to a specific car and they DON'T list what car they have?

Nissans can have a habit of fuel leaking past the injector seals on the side feed style injectors. When this happens the pressure in the fuel rail empties into one or more cylinders when you turn the car off which in turn finds it's way down into the crank case. Over time the buildup of fuel in the crank case thins the oil to the point where it starts to burn off. The oil analysis could easily prove whether or not this is the case. This scenario was much more prevelant on the older VG30 Maximas that had the injector recalls. Alot of them went in for the recall and were operated on by Techs that improperly seated the injectors. But it can happen on any side feed fuel rail.

bill99gxe

iTrader: (1)

http://forums.maxima.org/showthread....hreadid=100060

But you're welcome to Paypal me $20 for the hell of it.



With your MPG issues, you may not be able to extend your drain intervals much. Perhaps an Amsoil filter changed at 4k and 8k drain intervals would be possible....I know that if I lived in my car as you do I would seek ways to not have to stop at every oil change place while driving.


I would change the oil and sample now (5k or 6k) and then go from there based on the results. You can order an oil analysis kit from Mark as well, it just goes do a different but just as capable lab for analysis.

ardika

iTrader: (3)

Bill

Thanks for the link. I will order it sometime soon. You know, I don't live in my car... my job requires me to travel a lot (by plane). I don't use the car on weekdays. My office is only a 10 minute walk from where I live. I only use the car on weekends to visit my friends in Madison (Milwaukee-Madison 80 mile each way). Sometimes I also go up to Green Bay/Clintonville for job related travel.

But I refuse to say that I live in my car.....

*I* personally believe that my current drain interval is fine (5k/10k). My goal in using Amsoil is to save operating $$$ while maintaining the car's requirement. My calculation is: If I could spend around $50 for a year's requirement of oil change, that would be perfect (0w30 with 2 oil filters). I also want to reduce my "downtime", which is the time needed to change the oil (it took me about 1.5 hour to change the oil myself because I need to place the wheelramps, etc.).....but not the expense of "worrying time" (which is when you ask yourself at 5500 miles interval whether you should have changed the filter/oil before you take the trip). Or, will my piston rings are fine? How about the rods?

You know........nightmares of oil gods....

ardika

iTrader: (3)

SR20DEN,

The car is 97 GXE, I did not list it since I thought all 4th gen should be pretty much the same in terms of lubrication parts, etc.

Thanks for your info, but I do not see any fuel leak since my fuel consumption is pretty much normal. I also use the car only on weekends, and it always start right up (no flooding).

Having said this, I will look into it after I get the analysis back.

SR20DEN

iTrader: (7)

And how was I to know you even had a 4th gen?


The type of fuel leak I spoke of you will never actually see. Think of it as internal bleeding.

iwannabmw

iTrader: (3)

The only thing I can think of here is that the filter is plugging up enough to go cause a significant pressure increase in the system. Since the engine is going to have to work harder to power the oil pump, more fuel is going to be consumed.

ardika

iTrader: (3)

I agree with you, Mark, for the case with the Amsoil. However, my case with Castrol Syntec is definitely both (Fram *and* the oil).

As you know it, I am ordering the Amsoil filter from you. I would like to see how the filter is going to last.

iwannabmw

iTrader: (3)

I'm curious to see the results with the Amsoil filter as well. I've used them for 8k and never noticed any change in fuel consumption, so the results will be interesting.

ardika

iTrader: (3)

Mark,

This is the way I track my mpg. I put them on a chart every time I fill up and track my mpg from there. So, I am looking at a trend basically. Every time I put a value in there, I put some descriptions regarding that particular tank (city driving, highway driving, etc.).

What I notice is, there would be a downhill trend starting when I need to change the oil filter/oil. The same thing happens when my intake is dirty (Stillen intake, cone filter, cleaned every 15 or 20k), or there is something wrong with the engine (when one of my O2 sensor broke down, the mpg is definitely sucks).

I also notice that the AC compressor is taking a toll on the mpg, and in the winter, putting that sensor know all the way to the maximum in order to produce maximum heat right after your car has been sitting for a while forces the engine to get host fast, an in turn takes a toll in your fuel consumption. This does not apply when you only put the slider not in the maximum.

Another thing, heavy wind definitely takes quite a bit of mpg as well. Around 2 mpg for strong head wind.

How do I know all of these? Well, I travel in the same car on the same roads with the same tires and tire pressures (check the tire pressure every week). I usually drive normally, meaning, the car only sees 5k rpm and above once in a month or so. WOT is only, like.... three times in a month (only to perform in emergency situation). The car only sees around 1k-3k normally, with sometimes 4k...If I really need that "pull" from 3-4k due to Stillen intake.

I understand that you might not believe me, but I believe that the mpg is very useful measurement in monitoring my car's sytems. I know you might think I am crazy, but it's my 2 cents.

If my car is getting "only" 22 mpg combined here in Milwaukee, I am pretty darn sure something is going wrong under my hood. Of course, if I am getting 22mpg in New York City, I would actually be smiling.

iwannabmw

iTrader: (3)

I didn't mean to imply that I didn't believe you, I just never noticed any differences I could attribute to an oil change interval. I didn't track the mileage like you did either. All I did was divide the mileage on the tank by how many gallons it took to fill it up. Driving in the NE is hardly consistent as well. It will be interesting to see the results from your car in the next few months.

ardika

iTrader: (3)

Mark,

No offense taken, and sorry if I was too harsh on my previous post. I was referring "you" as general audience (you know, the ones who is thinking to flame me and so forth).

Yes, it would be interesting to track my car after a few months. I am just feeling too lazy right now to take a sample...... but I will do it when I am replacing the oil with the batch that I ordered from you.

Armand