By on October 29, 2014

moonroof.  Shutterstock user JADEZMITH

CJ writes:

My name’s CJ I have a 04 (Malibu MAXX) with a 3.5 V6 and I have the same problem with the car running hot (as Part I) but here’s the kicker :when the a/c is on the it runs normal, completely normal under both situations.  I’m thinking fan switch, but the radiator sounds plausible. What’s your take and is there something in between all this that I’m forgetting?

Sajeev answers:

Oh Dex Cool, how you keep my coffers full of automotive queries!  I shall never go hungry as long as the metal forced to circulate you, oh Dex Cool, continue to roam this land.

Keep in mind there’s two fans on this vehicle, one is a secondary blower (sucker?) to help when the A/C kicks on. (Remember kids, the A/C condenser is in front of the radiator.) Which begs the question, does your primary fan work?

Let’s assume the primary fan works, otherwise the engine woulda overheated and warped itself by now.  Warped like an overheated I-6 Supra or 3.8L V6 Ford, that is. If the secondary fan is needed to assist the primary, all signs point to a clogged radiator. Just like Part I: the solution is a new radiator and a cooling system flush to get the gunk associated with Dex Cool out of the system.

Or maybe I’m just lazy, as recycling answers is a sweet way to make the nut.

And with that bizarre ending, off to the Best and Brightest.

[Image: Shutterstock user JADEZMITH]

Send your queries to [email protected]com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.


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23 Comments on “Piston Slap: Cooling to the MAXX? (Part II)...”

  • avatar

    CJ Maxx.

    There’s a joke in there somewhere.

  • avatar

    Sounds like a possible lack of airflow through the rad. Check for any debris clogging up your radiator and condenser fins on the outside and clean them out as best as possble. It’s not always easy to get in there. The rest of Sajeev’s advice is sound, make sure all your fans are working correctly. If you’ve never had the coolant flushed, now may be the time before going straight ahead with a rad replacement. What comes out of the system at the time of flushing may indicate if you have debris causing poor circulation.

  • avatar

    Gadzooks! Why does this Hellish substance even exist?

  • avatar

    Trust me on this one. Dude..your rad is plugged. You can try flushing, but I’m thinking you need a new rad.

    I’m a long time GM owner, my kids, my relatives, all my friends at one time or another owned on of these. Its you rad

  • avatar

    If there’s no leak you have 3 choices: radiator, fan relay, thermostat. Decide whether you want to attack the most likely cause first, (see order above), or begin with the cheapest (reverse order).

    • 0 avatar

      10 year old Chevy. If CJ likes it, why not replace the radiator, the hoses, the thermostat, fan relay and anything else that comes to mind. Sounds like a good use for $600, if it gives another 5 years of peace of mind. While he’s at it, might as well get after the water pump and belt if there is one.

  • avatar

    Just hot-wire both fans. It makes it sound real ghetto every time, before you hit the starter. After that, who cares? And this way, the fans are always in fail-safe mode.

    • 0 avatar

      Isn’t that assuming the primary fan is inadequate, and it’s not the well-documented Dex Cool clogged radiator? If it IS a (likely) clogged radiator, having both fans on all the time will eventually not work. That’s like kicking the can down the road.

      • 0 avatar

        Yes. Kick the can down the road. If you’re keeping it til the end of time, it’s far cheaper to do near zero maintenance, and deal with the consequences when and if they happen. Including a used engine. If you’re not keeping it forever, why bother? It’s a Malibu. Drive it till it dies. Used parts will always be around.

        The point of the game is to spend as little as possible. The OP agrees, or a shop would’ve fixed it by now.

  • avatar

    My old Saturn had this issue. It had 2 coolant tempruature sensors, 1 for the gauge and one for the PCM. The PCM one went bad so it never knew it was hot and never kicket the fan on. However switching the AC on automatically kicked on the fan regardless of temp. It behaved exactly as you described which would lead me away from the radiator since it would probably run hot regardless of the AC being on or off if it was plugged. When it is running hot with the AC off is the fan operating?

    • 0 avatar

      @ mkirk: thanks, that was bugging me. Plugged radiators with flow restrictions on the coolant s!de shouldn’t see much improvement from an additional fan. If your GM knowledge specific solution doesn’t work out though, it’s possible the OP is running coolant through the heater core to compensate for running the AC when he wouldn’t normally. If running the heat cools the engine, it’s not too much heat from the engine (bearings and other reasons to swap motors) but inadequate cooling system performance.

    • 0 avatar

      This is my thought also. I would focus on the fan first.

  • avatar

    Are those Astro van vent windows on the roof???

    Why do they vent toward each other?

    Hmmm. I got nothing.

    • 0 avatar

      Nah, those windows don’t open. What looks like handles are actually sunshades.

      I had one for a while. I liked it, actually. Wish they still made it.

    • 0 avatar

      The MAXX overhead window is a solid piece of glass bonded to the roof. The tabs are for opening/closing sunshades. Early MAXXes had problems keeping the shades closed (handles would pop loose from restraints – reinforcement fixes were added during 1st year production).

      My former MAXX was a good trip car (very comfortable seats) but felt half finished (true of the new Malibu the Maxx was based on, so said Bob Lutz in one intervies) with herky-jerky cruise control, el-crasho rear suspension (no hydraulic bushings back there (front had them)), endless front suspension problems, and a weak “kill power if no traction” traction control system. Pity GM decided to cut and run on the MAXX rather than refine it.

  • avatar

    Checking if the fan functions properly would be step one.

    Dexcool works fine as long as you maintain proper fluid level.

  • avatar

    Its a problem with your fan(s) most likely the coolant temp sensor or if they use a separate fan switch on that model the fan switch.

    The fact that it doesn’t overheat when you turn on the AC indicates that it is indeed a fan problem. If it were a clogged radiator turning on the AC wouldn’t make it better it would make it worse if anything.

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