Piston Slap: Cooling to the MAXX? (Part II)
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 sajeev@thetruthaboutcars.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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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?
Are those Astro van vent windows on the roof??? Why do they vent toward each other? Hmmm. I got nothing.
Checking if the fan functions properly would be step one. Dexcool works fine as long as you maintain proper fluid level.
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.