When to do tune-up?
 

My Explorer has 172k on it, I bought it with 150k. It runs fine, only has a slight engine vibration/warble when idling. I don't have any idea what kind of maintenance the previous owners did on it. It seems well maintained, though, because of how well it runs, looks, and feels.

Should I just take a spark plug out and see how it looks? I forget if these need specifically torqued when put back in though? Or are there any other tipoffs to when it may need it?

I get 17-18 mpg on the 70 mph highway, 19-21 on the 55 mph highway I take to work (in the summer, it's down around 17 now in the winter). The EPA estimates 19 on the highway. I just kinda figured I'd get quite a bit better mileage on my trip to work since I drive at the supposedly great mileage speed of 55.

I'd have recommended you did a tune-up when you got the car. I did one Sunday on the Durango and I'd gotten it the day before. Mostly as an exploratory mission.

The plugs being pulled tells you how the engine is running, getting it up on a lift(or getting under it) tells you if people decided to go off-roading in it and messed up or any collision damage that might not be on the carfax, changing all of the oils tells you a lot too. In my car they'd changed every oil in the thing and it barely had 40k miles on it when I got it Saturday. Diff oils, transmission, t-case, and coolant had all been changed.

Granted, that should probably have been checked before the car was purchased but with me it was a major rush to get into a vehicle.

As for your plugs specifically, I've worked on a couple of those explorers and if you are going through the hassle of taking one of the plugs out you might as well do them all. Plus, one plug won't tell you the whole story, you want to pull all of them so you know if one injector isn't firing right or something.

I've been under my Explorer numerous times, as I've done all the previous oil changes as well as changed out the shocks and muffler. It all seems pretty good and surprisingly clean. Though it was nearly out of rear differential oil when I bought it. Unfortunately didn't find that out until a couple of weeks later :(. But surprisingly there doesn't seem to have been any obvious damage from it, as that was nearly two years ago.

I also forgot to mention that I only get about 13-14 mpg around town, and the EPA estimate is 15. I just figured with the way I drive (conservatively and mileage-conscious) I'd be getting a little better.

I see you have a Durango, do you know much about them (historically)? I only ask because my mom's Durango, I forget the year but it's late 90's, has suddenly decided to plummet the mpg. She claims to now only get 7 mpg and really not much better even on the highway. Do you have any idea what could cause this? My stepdad is pretty big on maintenance so I think it has been handled all right in that regard.

umm have u checked the rear differential since? that oil should not go anywhere unless theres a leak(either from the pumpkin or out the axle shafts into the brake drum)

also grease/check the u joints on the differential, those can cause vibrations.

repack wheel bearings, check brake pads, check fluid levels, change fuel filter, change pcv valve/breather filter, check to see if all the lights work

regarding your moms durango i know on other cars if the O2 sensors take a dump usually cause low mpg yet still runs fine(goes into some factory default thing thats typically rich) that and its a dodge :D

So far I think I'm averaging about 2-4 mpg above the all city rating of 11.

The O2 sensor can't be completely dead because OBD2 would complain but it could be reacting slowly causing worse mileage. Was it a sudden drop in mileage? Maybe the switch to winter blend? We have that here tho...

I agree with VetteOwner, check for leaks in that diff.

A few ideas...some of which may or may not apply to your Explorer or your mom's Durango:

O2 sensor failure would probably throw a code. If the O2 sensor is providing a believable (but wrong) signal, I imagine it could make FE plummet without throwing a code.

Tire pressure, or changing to different tires, could cause FE to dive and the driver may not give it a second thought.

A locking torque converter that lost its ability to lock might not throw a code.

An automatic transmission missing its first or fourth gear can conceivably go unnoticed. Maybe even third...but I don't think missing 3rd on those vehicles would cause a large FE hit.

A failing belt-driven accessory (alternator, steering pump, etc) could work but drag a lot, I guess.

Deferred maintenance, as you suggested, could cause it, especially if there's lots of stuff that wasn't done. Spark plugs, wires, fluids, air filter, etc. Edit: Also EGR, PCV, that kind of stuff.

Dragging brakes could manifest as a FE drop without other symptoms.

Wheel bearings on modern vehicles can fail with seemingly no symptoms, or any of a million normal or intermittent symptoms. I've been through a lot of wheel bearings (it's my weakness; I beat the hell out of them, I refuse to slow down for bumps, off-roading, or curbs). If all four wheel bearings have failed silently, they could cause a lot of resistance, and maybe only do so once heated up. Here's a few tests:
- Classic tests: Raise the vehicle, grab the top and bottom of the tire, and try to wiggle it by alternating pushing/pulling the top and bottom.
- Drive and listen for what sounds like aggressive tire noise.
- Raise the vehicle and see if the wheel spins freely. This one may need to be done immediately after an extended highway-speed drive to heat up the failed bearing.

Winter can drop FE significantly due to winter blend gas, extra idling, cold air, increased electric usage, and other things.

I could see a missing first gear going unnoticed.

Checking tire pressure would be another good idea. The tires in my car were 20psi low when I got it. You couldn't really tell except that the ride was softer than it should have been. Even that low the side walls didn't really look to be buldging much more than usual inless it was parked unevenly.

Thanks for the replies. Lots of things to think about/look into. Don't worry, yes I've checked the differential oil level since then. About......80 times :). I was pretty nervous about it so I got OCD on checking it. It hasn't gone down at all since. So I don't know if somebody did some work back there and just forgot to put oil back in or what. Strange.

I've done the push/pull and up/down tests on my wheels before, as I had a noise in the front end when I went over bumps when I first got it. My stepdad was all worried about the wheel bearings because he had just changed them in his sister's F150, but mine checked out fine. The shop recommended changing upper ball joints, so we did, and clunk was still there. Finally a year later a mechanic got smart and found out it was just sway bar bushings on the frame (I wondered if it wasn't just this the whole time, but there was beginning to be a little play in the wheel so ball joints needed changed anyways). Wish they would have found that $60 fix before the $500 ball joint suggestion. But oh well.

I thought about the O2 sensors on the Durango and told my mom to think about those. and yeah, Dodge wouldn't be my first choice either, but my stepdad loves them. So what can you do.

The original question asked about a tune-up.

Modern engines, and vehicles, have nothing to tune up.

There are replacement items; brake pads, fluids, timing belts, wiper blades.

Here are some things you ought to do:
*replace brake fluid about once a year. Sooner if you are in a humid or wet climate.
*replace differential oil at the 50,000 mile range.
*replace the power steering fluid then too.
*change transmission fluid at the proper time.
*change anti-freeze...'coolant' to you youngsters, yearly. Distilled water only.
*change your 100,000 mile sparkplugs on time. Might add upgraded wires then, if you've got em.
*rotate the tires every 5-10,000 miles.
*buy a liftime alignment and have the alignment done at 10-20,000 miles
*check serpantine belt idler and tensioners which can get out of alignment and you'll think the belt is bad.

You may, but don't need to, replace hoses and serpantine belts.

Never use Stop Leak except to get home from the middle of the Mojave Desert, as it just plugs the heater core and radiator.

You do not need additives of any kind, anywhere; if you use a top of the line lubricant such as those from Amsoil.

lol tons of stuff on modern vehicles to tune up, just as same as before! cars havent changed much at all since 1909.

definately change plug wires when you change plugs, they wear out faster than good plugs anyways.

brake pads/shoes check them but only repalce when theres less than a 1/8" left, or if they squeak when you press the pedal(that metal tab rubs on the rotor causing a squeak and tellign you to change them)

id leave the brake and power steering fluid alone, its just a big PITA and a waste to be changeing it since thier both closed systems there shouldnt be any contaminants of any kind in them. i only replace them when i have to service either of them where i have to drain the fluid/bleed brakes anyways.

same with antifreeze, it has a 5 year 100,000 gurantee on it and if its not changing colors leave it alone.

I know they say plugs are good to 100k miles but I'll be honest, every 100k mile plug I've seen pulled from an engine only barely made it to that number. I'd highly recommend changing the plugs before that time.

Not only do modern cars need a tune up but they have items on there you can't just do yourself. You can't just rebuilt a set of fuel injectors like you used to be able to do with carbs, they need flushed and flow matched. But, some maintenance depends on how the car is driven on a new car. Frequent short trips lead to needing fuel system work on an EFI vehicle but long daily trips or frequent highway trips usually mean you won't get the wax buildup that causes a need for injector cleaning.

I'm sorry, but with the new speed sensitive power steering and antilock brakes both those fluids needs to be flushed, at least every 100,000 miles. My mother had problems with her old 97 Century wagon with antilock brakes. She had to put new pressure sensors in it because the brake fluid wasn't flushed before.

When I took my truck in for the 150,000 mile service last spring I made sure absolutely every fluid was flushed and filled. (With the exception of the washer fluid tank, LOL)

-Jay

Vette Guy is wrong!
Na, na, na. Just funn'in here.

Differentials, transmissions, steering resivoirs, gas tanks, engines and brake systems, even cooling systems...all have openings to outside air.

And air has in it the number one Greenhouse Gas, the one not included in the Global Warming/Climate Change theories we are all in a panic about...Whddah!

And water, being heavier than oil, sinks to the lowest point of any system, which is why old brake cylinders and caliper pistons have rust in them.

yea they have vents but its not like engine oil thats getting extreme heat and carbon blasted in it.

trannies i can understand especially automatics but manuals i change those every 80-100K miles since its just used for lube.

ive never had a bad fluid related steering problem... ive had leaky PS pumps that go low and cause a heck of a noise. even in old cars ive never changed it.

old brake cylinders and the like rust because of outside air, yea they get some in the lines but majority is from outside moisture and condensation.

yea i agree that changeing them at 100K is a good idea but deffinately not every year, thats just a waste IMO

I must be OCD. I change my tranny fluid once a year (royal purple ATF) in my stick shift.

Engine oil + filter every 4000 miles (royal purple and K&N filter).

Spark plugs are copper core NGK's - replaced at the same time (factory plugs - do NOT waiver from the factory recommendations or go for fancy multiple prong crap unless the manual says you need to).

Spark plug wires get replaced at the same time.

Brake fluid flushed once a year.

Coolant hoses, replaced once every 2 years.

Serp belt and tensioner - replaced every 2 years.

Brake pads, hydraulics, and rotors - checked during oil changes, replaced every 2 years.

Parking brake cables - adjusted as needed every oil change.

Thermostat - replaced once a year.

Fuel filter - replaced every 2 years.

Power steering fuid - flushed every 2 years.

Suspension, drivetrain, mounts - inspected every oil change, replaced as needed.

Sensors and modules replaced when they are on the outer limits of service specifications.

Yes, a lot of good parts are taken off and replaced with new (lifetime warranties are great - especially when "customer satisfaction" is a valid reason for a return). But, very, very rarely does a common maintenance issue put my car out of commission. I've never had a stuck thermostate, brake hydraulic, broken belt, weak tensioner, etc. for a reason.

Wow, you do get rid of a lot of good parts.

In 7 years and over 200k miles of driving not a single one of those things have ever left me stranded. Only an alternator failure has ever left me stranded with no option but to wait until the ordered part came in.

If you regularly inspect things and know what to look for you are usually okay. I check my oils once a month usually, the Durango was getting checked much more often because I didn't know it yet but now it'll go down to one check per month. If you know your car checking everything every time you get gas is just overkill. In fact I don't do much more than just check the level of coolant and brake fluid most of the year. Once or twice a year I actually look at the quality of it but I know where my car has been and how it is driven.

Seems a tad bit excessive to me, but if you can afford it, and you have the time to do all that then go for it.

Yea how about you give me your Royal Purple left overs?:D


This is the only thing that I think is not excessive. My father's friend has this philosophy. He runs his cars to the ground and has never had to replace a brake caliper. It's good preventative maintenance.

Here's my total breakdown:

Every fuel stop:

Fill tank, reset trip meter & Scangauge, Check oil, tranny, PS, brake, and washer fluids. Visually inspect tires for signs of overinflation/underinflation/damage/abnormal wear.

And yes, I do go through all that when I get fuel. I usually spend 30-40 minutes at the station.

Every 5,000 miles(or 1 year if under 5k driven in a year):

Oil change (Mobil1)/filter/grease chassis, check ALL fluids. Rotate tires. Check tire pressue with a gauge, even if they look ok. Load test battery and alternator. Check all lights. Inspect wiper blades.

Every year:
Virginia state safety inspection.

Every 2 years:

Va state Emissions inspection. Tranny fluid flush, change differential & transfer case fluids. Brake and power steering flush. New air & fuel filters.

100,000 miles:

New OEM plugs wires, cap & rotor.

10 years/150,000 miles:

Radiator flush, refill with coolant/distilled water.

I think I got everything...

-Jay

I can see how you could spend that long....if you had my Tundra. It has no transmission dipstick.

The lifetime warranty parts and term limited ones get replace often - not at any cost tome though.

But ya know what? The car isn't busted and keeping me from going to work or living my life.

I never could understand the logic in this that manufacturers are using. Toyota, Izusu, and (if memory serves me right on this last one) BMW have done this previously or are still doing this. Not only is it impossible for you to know if you're low on fluid until your transmission has problems - but it's also impossible to refill it without tearing off the pan or finding some plug hidden like a spec of sand in a glass of water.

wait what? i think you contradicted yourself lol

but i agree with your error, weve never changed the fluid on some of our cars and have never had a caliber sieze. only ones that were siezed was because they sat for years.

when they do its from outside moisture in the air going around the piston and sliding surfaces not from moisture in the fluid...(just like rotors and drums rust over)

that and i believe the brake system is a closed system....

On the issue of tune ups, I have run many sets of Bosch platinum plugs over 100,000 miles and they weren't missing when I changed them, but just thought it would be a good idea to get new ones in. Even when running the plugs that long I didn't see any decrease in FE.

jeep45238
If the transmission leaks seriously enough that additional fluid is necessary, there will be clues, like those little oil spots all over the back of your vehicle.
By the way; leave the back down and roll up the sides. It's cleaner.

As to no dipstick on the Toyota; I have not checked but I'd guess there is a clever little sensor that turns on a dashboard light, like there is for the engine oil, when the level gets dangerously low.

VetteOwner
Check the filler cap carefully. All caps I've seen have a complicated valving system to allow air to enter as the fluid level goes down as the brakes are applied.

Just change them. Especially since you bought it with 150,000 miles on it and don't know when they were changed last. You will probably get between 1-2 mpg improvemrnt. Use OEM. Check the emissions sticker under the hood for the plug brand and # and gap.

Plugs are cheap and doesn't take long to do, and it is real easy to do on an explorer, and you will be glad you did it.

Just my opinion.

they don't, they have a rubber diaphragm that gets "sucked down" when the fluid goes down from the air on the non fluid side forces it down(pressure differences)

it cannot be vented, if it were it would attract moisture and be water in a year. That's why they say to never use old brake fluid if its been opened before or if its sat with the cap off it for a long time.

Don't know about rubber. I pulled the....rubber cap...off my resivoir and there was a nylon structure of some type in there. Some day I'll look closely, if I get bored enough to look again.
I've heard from the likes of Junior Damato and Click and Clack, that brake fluid should, ideally, be replaced every so-often.

Yeah, not flushing the brake fluid seriously screwed up the ABS system on my mom's old Century wagon. If my memory serves correct we had to replace all the ABS sensors and the master cylinder to fix the problem.

-Jay

Flushing ABS systems in the traditional brake flushing method will NOT work at all.

Flushing them where you haven't done that for oh...10 years or so is not a good idea - the bits of rubber hoses can clog up calipers pretty damn good.

The Century wagon was only 3 years old with 140,000 miles on it at the time. I don't think age was a factor. We were told it was because the brakes weren't flushed as to why we were having problems with the ABS system flashing the dash light.

Flushing ABS systems in the traditional brake flushing method will NOT work at all.

Flushing them where you haven't done that for oh...10 years or so is not a good idea - the bits of rubber hoses can clog up calipers pretty damn good.