Piston Slap: RTFM FTW

Sajeev Mehta
by Sajeev Mehta
piston slap rtfm ftw

It actually comes with a little book too!

Patrick writes:

Hi Sajeev,

Avid daily reader of the site but infrequent commenter… Pony Cars and old Volvos sometimes drag me out of my shell but I have a couple questions about my wife’s car and I wanted to see what you and others might think.

We’ve got a 2007 3.5L Impala with 60,000 miles on it and it is due for an oil change and checkup:

1. Am I crazy for trusting the car’s computer to tell me when to change the oil? The car monitors oil life and reports a % of oil life remaining and nags me when it’s time for an oil change. The owners manual doesn’t specify a mileage interval instead advising to change it when the car’s info center says it’s time. It typically runs from 8K to 11K miles between changes so far.


The dealer would rather us get it changed at every 3K and are so desperate to get their fix of oil change traffic that they offer a “free tires for life” deal if you stay on the 3K schedule with them. Factoring in the cheap tires they get at cost that they’d slap on there, they’re most certainly coming out ahead (which is why they do it, of course); factoring in the extra services and the mounting and balancing fees for those free tires, it’s probably a wash for me so I’ve declined and followed the car’s schedule instead of there’s as


I’d rather save up for that next set of tires than have to go in to the dealer 3 or 4 times as often.

Now, I know I don’t have to take it to the dealer and while I do almost all of my own service, repairs and upgrades on my car, wrenching on our utilitarian transportation-mobile isn’t nearly as rewarding and I don’t mind throwing the Chevy place a bone every once-in-a-while, especially since their service isn’t much more than the quicky oil change places and, theoretically at least, they should be intimately familiar with this generation of Impalas – plus if and when it comes time to trade it in or sell it, I’ll have nice official looking dealer records to go with it.


I figure GM did their homework with the oil monitoring system and I’m comfortable with longer oil change intervals – I do 6K ~ 7.5K on my Mustang (’96 GT) which has 130K+ on it and oil still comes out clean and when I had the valve covers off last year, the top of the heads were clean as a whistle. With the Impala PCM monitoring temps and driving usage and whatever other variables it factors in, I’m willing to let it ride a little longer if GM says it’s OK. Have you heard anything that would give me reason to believe otherwise?

2. When I realized 60K was coming up, I rushed to the owners manual to see what expensive work the dealer was going to want to do – then I remembered this wasn’t a European car and there was nothing other than greasing door hinges and locks and inspecting a few wear items that needed to be done. I did notice that the book calls for a fluid replacement at 150K miles for the 4T65-E transmission (or at 75K for severe duty). After reading some of auto transmission horror stories here but not being aware of any endemic problems with GM’s transverse V6 transes is 150K too long to go, should I plan on doing that sooner? 100K, 125K, if we still have the car that long or is GM pretty close to the mark on that?

Sajeev answers:

I never thought that answering a GM W-body question would be a breath of fresh air in my Piston Slap queue, but well, here we are. Patrick has valid and relevant questions to anyone with a less than desirable ride that does the job and keeps you mobile. You know, cars for the vast majority of us!

So let’s do this thing:



Question 1:
by all means, ignore the dealer when they pull the “free tires for life” and 3k oil changes. Like you said, I wouldn’t leave them entirely, as their pricing should be comparable to the quickie oil change places, but you need to get the playing field level: remind the service writer that you’re familiar with the phrase RTFM. And you expect them to treat you accordingly. The “do this to be more proactive” tactic you mentioned works on some people, and that’s fine. But that’s obviously not you or anyone else here. It’s all about treating the customer with respect.

I trust that oil life meter after years of questioning it via dipstick eyeballing. Now that I run synthetic oil (in cars that never officially required it), I change the oil after about 180% of its life: that is, resetting it once and then changing it when its 80% used. It seems like the smartest way to not waste good oil, and my driving conditions merit it: lotsa traffic, heavy engine loads (aftermarket stereo, A/C) and brutal Gulf Coast summers. The 180% mark turns into 6000-8000 miles of my commute. Which is fair for synthetic oil.

It works for me, maybe I should take my used oil examined to a lab to prove it to everyone…but I don’t really care since it’s been working for well over 175,000 miles on my very, very healthy Lincoln Mark VIII motor. Healthy enough to let me (cautiously at first) trust the life meter on other cars too. More to the point, your driving conditions can and will vary.



Question 2:
there are no endemic problems with this GM transaxle that I know of, but I would still change the fluid before it hits 100k out of principle alone. Again, this depends on your driving/climate conditions, but my gut tells me you should change the fluid according to the severe duty schedule in your owner’s manual. Transaxles in general deserve the “severe” fluid service schedule, and this Impala sounds worth it. Be it a flushing machine or the conventional drain and filter replacement, just make sure all the fluid is changed…don’t let old fluid rest in the torque converter and mix in with the new stuff.

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry.

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  • Doctor olds Doctor olds on Feb 05, 2013

    @Zackman- Your usage supports particularly long change intervals since most of the time your engine is running it is fully warmed up. You can save some money by letting the oil life warning tell you when to change. If you want to be conservative, change it at 80-90% oil life. Can't go wrong changing more frequently, but you may waste your money.

  • 28-Cars-Later 28-Cars-Later on Feb 06, 2013

    Patrick I have the Pontiac equivalent to your Impala and I believe both W's use the same transmission. I asked the transmission fluid question of my Aamco guy, he replied and I quote: "here [in Pittsburgh] you have extreme heat and extreme cold coupled with a very hilly landscape. If this were Ohio you could probably stick to 50,000 miles, but here I would drop the pan and change it every 25,000 or so". I was changing mine at 55,000 shortly after I bought it. The other part of it that I ran into is the transmission fluid filter gets clogged/dirty just like any other fluid filter. I noticed the transmission fluid temperature (on the computer) would jump to 120+ degrees very quickly after startup. After my fluid/filter change on spring/winter/fall days it warms up slower than the actual engine temp, and never seems to get much higher than 116 (in local driving). I theorize it was jumping higher on start-up because fluid wasn't circulating properly to properly cool the transmission. My two cents.

  • Make_light I drive a 2015 A4 and had one of these as a loaner once. It was a huge disappointment (and I would have considered purchasing one as my next car--I'm something of a small crossover apologist). The engine sounded insanely coarse and unrefined (to the point that I wasn't sure if it was poor insulation or there was something wrong with my loaner). The seats, interior materials, and NVH were a huge downgrade compared to my dated A4. I get that they are a completely different class of car, but the contrast struck me. The Q3 just didn't feel like a luxury vehicle at all. Friends of mine drive a Tiguan and I can't think of one way in which the Q3 feels worth the extra cost. My mom's CX-5 is better than either in every conceivable way.
  • Arthur Dailey Personally I prefer a 1970s velour interior to the leather interior. And also prefer the instrument panel and steering wheel introduced later in the Mark series to the ones in the photograph. I have never seen a Mark III or IV with a 'centre console'. Was that even an option for the Mark IV? Rather than bucket seats they had the exceptional and sorely missed 60/40 front seating. The most comfortable seats of all for a man of a 'certain size'. In retrospect this may mark the point when Cadillac lost it mojo. Through the early to mid/late 70's Lincoln surpassed Cadillac in 'prestige/pride of place'. Then the 'imports' took over in the 1980s with the rise of the 'yuppies'.
  • Arthur Dailey Really enjoying this series and the author's writing style. My love of PLC's is well known. And my dream stated many times would be to 'resto mod' a Pucci edition Mark IV. I did have a '78 T-Bird, acquired brand new. Preferred the looks of the T-Bird of this generation to the Cougar. Hideaway headlights, the T-Birds roof treatment and grille. Mine had the 400 cid engine. Please what is with the engine displacements listed in the article? I am Canada and still prefer using cubic inches when referencing any domestic vehicles manufactured in the 20th century. As for my T-Bird the engine and transmission were reliable. Not so much some of the other mechanical components. Alternator, starter, carburetor. The vehicle refused to start multiple times, usually during the coldest nights/days or in the most out of the way spots. My friends were sure that it was trying to kill me. Otherwise a really nice, quiet, 'floaty' ride, with easy 'one finger' steering and excellent 60/40 split front seat. One of these with modern mechanicals/components would be a most excellent highway cruiser.
  • FreedMike Maybe they should buy Twitter now.
  • FreedMike A lot of what people are calling "turbo lag" may actually be the transmission. In this case, Audi used a standard automatic in this application versus the DSG, and that makes a big difference. The pre-2022 VW Arteon had the same issue - plenty of HP, but the transmission held it back. If Audi had used the DSG, this would be a substantially quicker, more engaging car. In any case, I don't get these "entry lux" compact CUVs (think: Cadillac XT4, Lexus NX, BMW X1, etc). If you must have a compact CUV, I can think of far better options for a lot less money. And, no, the Tiguan isn't one of them - it has the Miller-cycle 2.0T, so it's a dog. But a Mazda CX-30 with the 2.5T would fit the bill.
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