Towing Problem - Weird Noise
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Joined: Dec 2005
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Towing Problem - Weird Noise
Last week I was pulling about 7,500 lbs up the Hwy 20 grade from Grass Valley to Donner Pass (2003 PSD, stock, 55K mi) - ambient temp was about 95 degrees and I was pushing the truck pretty good (this was about the fourth hour of the trip back from Ft Bragg on the coast). I noticed that the fan had gone into high gear - I was probably going 55-60 mph with the truck in "tow mode" - tach speed was probably around 3K. I heard this weird sound - something like a "whrrrr-crunch" - that immediately made me think that the fan was slipping and then catching again. I looked at the gages and saw an elevated temperature - not in the red, but significantly above average. I took my foot off of the gas and got three "whrrr-crunches" in response, but within a minute the temp was back to normal. I backed off the accelerator and made it to the top of the ridge where I pulled over and let the truck idle for about 10 minutes before taking off again. No repeat problems. Anyone know what might have happened?
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Joined: Jun 2006
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my trucks fan dosent make a crunch sound when it comes on but the darn thing sure likes to get hot like you described whenever i pull a trailer ( about 2-3 needle widths below the "hot" line), and im only towing 3000lbs!
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Fan Clutch Details
Thanks for the replies. So, BowTieHatr, the supplemental fan does not kick in unless the Tow/Haul mode is engaged? Will have to try that next time - will be climbing up the killer west side into Yosemite in a couple of weeks. The noise was pretty weird, but definitely like the fan went to overspeed, then some crunching noises like gears trying to re-engage. I assume the temporary elevated engine temperature was because the fan did not re-engage properly.
