The Truth About Cars » Fluids The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. Wed, 16 Jul 2014 16:33:07 +0000 en-US hourly 1 The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. The Truth About Cars no The Truth About Cars (The Truth About Cars) 2006-2009 The Truth About Cars The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. The Truth About Cars » Fluids Piston Slap: Always Trust, But Verify Mon, 05 Mar 2012 12:35:11 +0000


Patrick writes:

Okay, I have a question. Strictly follow the manufacturer’s suggested maintenance schedule, or only perform demand maintenance?

Of course I love buying cars where the previous owners were diligent and could prove it. I do a hybrid, I change fluids regularly but do the rest as demand (with exceptions.) Timing belts on interference engines an example of an exception.

Sajeev answers:

As much as I’d like to say you always–without question–follow the owner’s manual, Toyota and VW/Audi ruined that delusional notion with their engine sludging problems a few years back. It doesn’t matter if its your significant other, ex-significant other, someone you wish was your significant other, mother, co-workers, best friend, or the dude that bags up your grocery: always trust, but verify.

The people behind the words in your owner’s manual have the best intentions, but nobody knows how every subsystem in every powertrain fares after 3-10 years of use.  It’s completely impossible to know without never-happening powertrain changes (i.e. Panther Love) so I shall say it again: always trust, but verify.

So let’s pretend that you, dear reader, actually give a crap about your ride. But you don’t have the time/money/interest to ship fluid samples off to see when exactly your oil, coolant or brake fluid isn’t 100% functional. So perhaps you should flush out the brake system on every 2nd brake job, just because you live in an area of high humidity and you feel the pedal in your car is too spongy. I mean, the mechanic is already working in front of every bleeder valve: why not spend a few more bucks for another bottle of brake fluid? Or change transmission fluid annually because you tow a lot of heavy things in your line of work. Sounds fair.

I often do an oil change when it smells a little smoky and has 8-10,000 miles on it. Or just do whatever the dash light says, as it considers your driving habits.  I have yet to hear that a maintenance minder came on when it was too late: they err on being conservative.

Your “Hybrid” notion can be a good choice, as long as it doesn’t justify something ludicrous like the 3000-mile oil change on damn near any car running modern oil.

Bonus! A Piston Slap Nugget of Wisdom:

Perhaps “trust but verify” is a dark way to live your life. But maybe it’s the best way to believe in yourself, making yourself accountable for the actions around you. Because we do have control over many aspects of our lives, whether we choose to exercise control is always a delicate balancing act of time/money/interest.

Example: I recently spent a ton of bread getting the Terrazzo floors in my new home wet sanded, chemically cleaned and then epoxy-coated like a race garage.  Turns out they couldn’t get the stains out, for a fairly good reason. Instead of getting pissy and demanding a lower price, I paid them and was on my merry way. I had no interest in fighting that battle. But I did trust them, and they let me down. I had no way to verify their process/conclusion at the time, so I gave up. I got bigger fish to fry.

And perhaps you do too.  So maybe you should just read the manual and listen to your dashboard.


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

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Pontiac Owners: Would You Buy GM Again For A Free Oil Change? Tue, 19 Jan 2010 07:06:20 +0000 (

Grand news for owners of 1999 model year and later Pontiacs! Buick-GMC GM Brian Sweeney tells Automotive News [sub] that “one of our most important tasks is keeping [Pontiac owners] in the database and keeping them as service customers until such a time that the Buick portfolio has developed fully.” The plan: send owners of 1999 model-year and later Pontiacs coupons for free tire rotations and oil changes. GM sales boss Susan Docherty has spoken about the importance of these “free agents,” or GM buyers orphaned by the cutting of their brands. As well she should: it’s more cost effective for any business to keep existing buyers than win over new ones. But is it free oil change easy? If GM thinks it can make Buick believers out of the jilted Pontiac faithful, what does it say about the cynicism with which it approaches branding? Once again, GM’s need to build lost Pontiac volume for the Buick-GMC dealer net leads to the willful suspension of common sense.

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Piston Slap: Nissan Matic J Worth The Trouble? Mon, 04 Jan 2010 15:09:46 +0000 Matic-depressive?

TTAC commentator Kericf writes:

First, an update: I submitted a question on my Rodeo ABS and brakes before. It was just a bad sensor (probably from driving in high water). And I chose not to replace the brake lines yet after inspecting them.

Now, my new question comes way of a transmission fluid change on my wife’s 2005 Pathfinder. As usual the manual calls for only using official Nissan Matic J at almost $13 per quart. The local auto parts store sells Castrol Tranny fluid that says on the label it is a replacement for Matic J. I do not have any warranty left so I’m not so much worried about fighting over what was used, I just don’t want to have to replace the tranny because the fluid wasn’t the right spec? Am I worrying too much about it? Should I just dive right in and go?

I would also like to get some suggestions by the B&B on the best way to flush more fluid out than the standard drain 5qt out of the pan method. Is there a way to really get it all out on your own? I saw the product review on the oil extractor and was contemplating trying one out for the tranny fluid as it seems a lot easier and cleaner.

Sajeev replies:

Congrats on the easy fix on the Rodeo! On the Pathfinder, use any fluid that meets the manufacturer’s specifications, and I suspect the Magnuson Moss Warranty Act agrees with me too. So yes, dive right in and go.

I seriously doubt the engine oil extractor (per TTAC review) has the balls to vacuum through the guts of a torque convertor; only the pressurized flushing systems can pull that off. If you’re lucky, you can pull the pan (and whatever trim covers the torque converter) and spin the converter 360 degrees and hope that Nissan gave you a drain plug. If not, I suspect the flushing machine is your best bet.

As previously mentioned on Piston Slap, your best bet is to do both a filter change and a flush of all the old fluid. Try to find a shop that can do both, unless your Pathfinder has well over 100,000 miles with original fluid, you might want to reconsider flushing the varnished fluid (filled with clutch material) with new slippery stuff, as that could wear out the transmission much faster. Fluid changes on old automatic transmissions are a tough personal choice, so think before you act.

Off to you, Best and Brightest.

(Send your queries to

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Piston Slap: Dodging Trouble Again? Mon, 21 Dec 2009 16:33:31 +0000 Time to get out of Dodge? (courtesy: Flickr/Chad Dunbar)

Tom in North Carolina asks:

Thanks for taking on the synthetic vs. standard oil change question on my 2005 Dodge Durango a few months ago. Now for a new challenge: the same Durango, 78,000 miles, 5.7 Hemi with 5 speed automatic (trailer tow package and transmission cooler). It’s a highway cruiser, bought it to tow a boat with trailer. Except I have a boat slip now so there’s very little towing needed.

The dilemma: the manual says nothing about changing the transmission fluid if the vehicle is not used in severe service. Since I am skeptical of lifetime fluids, I think the fluid needs to be changed but don’t have any idea when to do so (FWIW: it is still a nice shade of red on the dipstick).

My options:

1.The local Dodge dealer recommends that the transmission fluid be changed weekly (well, almost), with both internal transmission filters changed, at $250 per service. Since the transmission is a closed system, I can’t really see where contaminants could get into the system that would require that the filters be changed, but being wrong could prove to be very expensive.

2. The local Tire Kingdom will do a fluid exchange/flush for $110. I used to do this every 75,000 miles with an Isuzu trooper that had a sealed transmission and never had any problems when I sold it at almost 200,000 miles. Is flushing out all of the old fluid and replacing it adequate (as long as the correct fluid is used), and more than the service manual requires?

3. Do nothing. The whole power train is overkill/overspec’d for highway trips and will probably last forever with engine oil changes and the occasional set of 16 (!) spark plugs.

I want keep the vehicle for another few years, and maintain it appropriately. It is not a Bugatti, nor is it a clunker. I am not from the “change the oil every 3000 miles because that’s what daddy did” school, nor the run it till it breaks crew. This vehicle is a heavy duty appliance, and I want to maintain it as such.

Sajeev replies:

There is no wrong answer, especially if Chrysler (and their Lifetime Warranty) stays around as long as your interest in this vehicle remains. Then again, don’t hold your breath on that.

And transmission filter(s) have purpose, needing replacement at some regular interval. But the conventional “drop the pan” service is the only way to do it. Which, if your torque converter lacks a drain plug, cannot remove old fluid as well as the “flushing machines” at local oil change places. Confused yet?

I’ll simplify: find a place with a transmission flushing machine plus a service bay to do a filter change. Ask them for a package deal on both services, unless you do have a drain plug on your torque converter. (If so, do a conventional service and hope the mechanic drains the torque converter.) And do this in the next 20,000 miles or so. Repeat again in another 50,000-100,000 miles, depending on condition of the tranny fluid as the years go by.

There’s no rush: you’re on top of things. Your game plan for the coming years determines just how bulletproof this Durango shall be in the future. And, short of doing neutral drops at stoplights, you can’t go wrong with any transmission regiment you have in mind.

(Send your queries to

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