Archives

Well, I thought I'd front the question here. All through March, April, and into July, I was getting between 42-45mpg, driving in city, average trip about 10 miles (each way to and from work). So about 25 miles a day, 4 days a week.

Now, at the end of July, I took a small road trip from Denver to St Louis Missouri. Roughly 850 miles each way. I got back from that trip, having just pushed over my 3000 miles since my last oil change.

Now, a little back story, since I bought the saturn last november, I've had all of the oil changes done at the dealership. I was getting a discount, so I figured I might as well. I have no idea what the Saturn dealership was putting in other than that it was the 5w20 that was reccomended by the manual. I've since been told that the normal oil is akin to Valvoline durablend synth blends.

I took the Saturn to a Valvoline Instant Oil change and had them just do a basic filter swap and oil change with natural oil.

Since then, I can barely get 38mpg, no matter what I do. I have been averaging 35mpg or so since, but I have to drive it very gingerly, and all the tricks that got me 45 before aren't working to the effect they were before.

Tire pressure is good (max sidewall), fuel's stayed the same (from the same station every time), and this was a very sudden drop.

Would the oil be a likely cause of the FE drop? Would going to a durablend or adding a synthetic stabilizer like Lucas help increase my FE?

Thanks for any advice you all can give.

Hi Jalen:

___10 mpg from an oil change is not it. Even the switchover to Winter RFG will not cause that either. One item that could however is colder temps.

___Good Luck

___Wayne

That's what I thought at first, but there's only two big events that coinside with the drop in milage. One is the 1700 mile trip. The other is the oil change. But what about either of those would cause the huge change?

Unless of course they didn't put 5w20 in at the oil change...

How many tanks are you basing your info off of? Hang on at least another tank and see if your results stay the same. However it's worth checking a few things like:

air filter
battery
spark plugs

After a long trip it's possible that your car needs a bit of maintenance to get things tip-top again. Or just that the fuel happened to switch off later than normal, so your FE on this tank will be really high. Or your SG is miscalibrated or got reset for some reason.

I know my fuel log here does not go back very far, however I have been tracking the fuel on my own since I bought the car. My average was 42mpg over april, may, june, and most of july. My average for August (post trip and change) was 35-36, then September average is 33-35. If you look my Saturn up in the Mileage Log, you can see how it seems to go up and down a lot, but sticks at an average of about 35. (http://www.cleanmpg.com/index.php?page=garage&displayunits=MPG(US)&viewcar=2491) I'll give it another tank and see where it lies, but... I'm just not getting what I used to.

My air filter is clean, and I just replaced the plugs 2 tanks ago... They did need it bad. The battery seems to be ok too.

I do not yet have a Scangauge yet, I'm basing my numbers off of miles traveled/gallons to fill tank.

On a Saturn, one of the things that are important to keep an eye on is the coolant temp sensor. Another thing, if you have a fair amount of miles on the odometer would be to see if the O2 sensor might need changing. The one right there on the engine under the hood is usually good for 80-100K or so, I hope that helps.

Big change...

Cooler weather?

Is there too much oil in the crankcase?

Do all of the wheels rotate easily?

I'll take the easy answer. I'll bet the Saturn dealer was pumping up your tire pressure, and the Valvoline guys pumped it down. I'd check that first. Then check to see if they overfilled your oil. Also - you could bring it back to Saturn for your next oil change and see if it gets better. The Valvoline oil or filter may be of lesser quality.

Do your own if you can.

Also Valvoline oils and filters (IIRC a Champion Labs product) should be just fine. Well, maybe not the bulk stuff.

Pretty much any SM rated oil will do the job.

Check all that stuff listed above and see what shakes out.

Why are you doing 3K oil changes? Today's conventional oils can easily go 5K miles. I'm betting your owners manual states 5K mile OCI's. If your worried about going that far between oil changes then go to a synthetic oil such as Mobil 1. There is no need to be doing 3K mile oil changes with the quality of today's oils. Wally World sells gallon jugs of Mobil one for around $23. 15K miles a year 3 oil changes vs 5 with 3K mile OCI.

Would a pure Synth help me get better FE? I've heard that it does, but... I don't know.

Well, I got my oil changed, and they dropped my tire pressure to 30 in the front and 26 in the back. I asked them to fill them back up to the sidewall and they refused. Did have straight synth put in however, along with some Lucas stabilizer. Now, I filled up just before this with my new spark plugs and hit 37.8 mpg.
I pumped it back up to the sidewall pressure (35) myself, and today had to do some long distance travel. Came back to a nice 41. And all this without using a SG :P Gona take me some time to save up to delve into that.

I always air up my tires myself. I do it weekly - that way I always know that they are ok. The guys in the tire shops and garages are idiots. I once asked the manager at an NTW store to have his tech check my tires for sidewall psi and he looked at me like I had asked him to kill someone and then he launched into a tirade about how unsafe that is (max sidewall).

Well, I got my oil changed, and they dropped my tire pressure to 30 in the front and 26 in the back. I asked them to fill them back up to the sidewall and they refused...

Jalen, I'm immensely curious; did they specify why they wouldn't increase the pressures? I would have made it clear it would be my last visit there under the circumstances, for sure. I could understand if you were running max+ pressures, but not that they refused sidewall max.

Jalen, I'm immensely curious; did they specify why they wouldn't increase the pressures? I would have made it clear it would be my last visit there under the circumstances, for sure. I could understand if you were running max+ pressures, but not that they refused sidewall max.

Yes, they did. They stated that they will only fill to manufacturer specified pressures as per the plate on the inside of the door for liability purposes, as that is all the manu has listed as 'safe' pressures for the tires.

Can't blame their safety strategy too much; they are being cautious. (Of course we are slower and more careful when hypermiling at the higher pressures ... but they don't know that.)

I wiped out completely in the 94 Saturn recently in the process of avoiding an unattentive motorist who shot out onto the highway from being stopped at a stop sign .... to cross almost into my rightside. The 'maxed' rear tires lost grip in the evasion which took too strongly left ... overcorrecting back too late but fast (back-end this-time lost stability completely the opposite way) ... managed past him thanks/indeed to his last second braking. In that evasion process my Saturn's polymer side-panels barely escaped what would have been a brutal front Ford-van bumper by merely a few inches.

The resulting sideways slide had seemed long and helpless after that ... but gradually nearly backward-sliding ... hit one of those slim metal snow-guideposts with backwheels that spun/jerked the nose around/forward with slow-motion-entry into the opposing ditch ... and deepenough to hide the car. The Van-driver watches me exit the vehicle from 1/4 mile, then drives away as if nothing happened, leaving me there on the dark lonely highway for someone else to deal with.

POINT is: There was precious little rear-track stability in going left (escaping Engine to Engine contact with the bigger Van) ... but then by yanking right ... instantly lost the backend outwards inside that correction like having too little grip back there ... or as if cold pavement and colder rubber is somehow less grip overall. It was cold and frosty outside; yet the pavement was as dry as can be.

Perhaps this is why tire-care providers preach only the best tires and at propper pressures (6lbs lower in the rear) just for the unexpected event to provide some extra prevention.

I got the same 2002 5 speed in the yard (the wife drives it) and was getting just over 400 miles per tank consistantly ... lately it is getting less occasionally (like what you are saying).

We troubleshot a P0301 code with the new scangauge II ... after changing cables and plugs the engine still vibes on idle at stops ... which could mean EGR ... which is next on the agenda.

That tirepressure reduction operation (which happened at your oilchange) .... happens consistently to us at those lube-shops too.

[Colder weather is claiming FE as our climate begins to cool-off now in the fall. That, and increased front-end tire pressure, are two items that definitely make a big difference to FE on the Saturn.]

It doesn't help that around Denver, all fuel is E10. I have no idea what they put in during summer months, but in the winter, because smog tends to cling low to the ground, they put the full 10% in. Of course, I never noticed much of a differance when I went east into Kansas and started using 89 and straight gas vs the e10 87 they sell as midgrade up here.

I will say this though, every other state where they sell even e10 fuel, the cost is about 20 to 40 cents cheeper on the gallon. We get ripped off in the Mile High.

The old Saturn SL's are a rare breed... and very easy to work on. I would check the Engine Coolant Temp Sensor (as diamondlarry mentioned) and make sure it is the brass-tipped one and not the plastic one. They're $9.00 at Autozone. Also, I would clean the EGR (Exhaust Gas Recirculation) valve. It's the little cylinder canister looking thing on the right side of the valve cover. The O2 sensor in the headers may be getting lazy if it hasn't thrown a code yet. You may also be due for a tune-up. Standard wireset and copper plugs are all you'll need. Platinums and Iridiums don't tend to play nice in those 1.9's.

There are great directions and other suggestions on the forums (http://www.saturnfans.com/forums) over at SaturnFans. Check out the stickies and posts in the How-to-Library and check out the S-Series board as well.

Good luck, and let us know what you find.

Well, l put platnum plugs in, Boche. I have the SOHC 1.9l 4i engine. It's not too old and the miles are low. The platnum plugs actualy boosted me a couple MPG over the old ones. I actualy asked around to a lot of different mechanics and shops and all told me that a basic platnum plug was my best option.

I'll start poking around that saturnfans forums and see what I can find.

Thanks!

Well, l put platnum plugs in, Boche. I have the SOHC 1.9l 4i engine. It's not too old and the miles are low. The platnum plugs actualy boosted me a couple MPG over the old ones. I actualy asked around to a lot of different mechanics and shops and all told me that a basic platnum plug was my best option.

I'll start poking around that saturnfans forums and see what I can find.

Thanks!
I'm fairly certain that what you will find at saturnfans.com forums will be pretty much what I saw there: platinum plugs don't play too well with the SL engines. It seems to have something to do with the waste-spark setup of the ignition system but don't quote me on that as it's been awhile since I've been over there. From most of my reading there, they recommend the NGK V-Power plug which is basically a standard copper core plug with a v-shaped groove cut into the center electrode. The part number is BKR5E-11 for the SL2 and BKR4E-11 for the SL1. As an added bonus, they're cheaper too.:) The increase you saw was more likely due to just having fresh plugs.

So I've wasted a lot of money on those plugs I can't return now? heh. Figures.

....

We troubleshot a P0301 code with the new scangauge II ... after changing cables and plugs the engine still vibes on idle at stops ... which could mean EGR ... which is next on the agenda.
......]

Our 01 Saturn knows that code well--misfire on cylinder 1. I've worked my way down the troubleshooting list to intake manifold gasket leak which is reported to be a common defect for that code in aging SL1's. I haven't had the chance to dig out the old gasket yet. For us it's just a transient problem--mostly for other drivers in the family since I don't idle at stops much.

Our 01 Saturn knows that code well--misfire on cylinder 1. I've worked my way down the troubleshooting list to intake manifold gasket leak which is reported to be a common defect for that code in aging SL1's. I haven't had the chance to dig out the old gasket yet. For us it's just a transient problem--mostly for other drivers in the family since I don't idle at stops much.

That code... does it prompt a Check Engine light? Or does the saturn just ignore it and move on? I'm curious now to see if I need to hook a code reader up (no scan gauge yet) and look for problems.

Check PCV valve.

can anyone tell me off the top of their head... if I average between 35 and 38 mpg (its winter)... I just netted 37.48 with little effort... what increase will I see running max sidewall pressure (44psi) in the 2002 Saturn SL 5M... any other quick easy safe mods I can make to net better milage... 40+ with little effort and expense? btw sorry for the thread jack... same car... nearly 179k... looking for some good milage!

I'd like to know what you're doing to get that kind of FE in winter! I can barely keep it around 34 after the winter RFG went into effect and the temp dropped.

Also, 44psi tires? are they stock or aftermarket?