Hi there,
I think I've read everything on here (and other places) about fans/overheating/etc. - trying to clarify and hopefully get the right fix. A bit of a read - I'm trying to include all relevant stuff.
A few months ago while driving the D2, fully loaded, up a twisty range, I noticed the fan noise changed all of a sudden. It went from the normal noise to something 'fatter/softer' (hard to describe). It wasn't any louder or more quiet just different. I didn't notice any change in power and the temp guage didn't budge. Upon arrival I had a peek under the hood and all seemed well.
Since then, on the odd occasion, the 'different' note would return - possibly associated with the engine working harder but not obviously.
Its normal for the fan clutch to change fan speed according to heat load on the radiator, maybe you have become more aware of the changes since first noticing the different noises? Also the fan will be working harder in the hot weather.
A couple of weeks ago during a heatwave, we were driving hard up and down Mt Pinnabar, and just after returning to the blacktop (steep road heading to Jindabyne from Tom Groggin), the temp guage moved a up a few needle widths and power was down/turbo lag much worse. I didn't think this was the ECU limiting power as the needle didn't move too much so I considered the airfilter might be clogged - the dust and water crossings (I have no snorkel) seems to clog them bad. I pulled over to swap out the air filter and the electric fans were working even when shut down. Upon startup, the needle was still slightly elevated and it returned to normal after a minute or two; power/turbo lag was normal again too.
Is it possible you didn't give the fan enough time to do its job after the fan clutch had just increased the fan speed ? (particularly if the engine was working hard just before you noticed the gauge movement)
As the needle has never moved before, even under extreme conditions, there's something amiss but what is it? The airfilter was no worse than I've seen before. Bung viscous fan; clogged radiator, dodgey water pump, dodgey sensor? I don't think it's the thermostat.
I've been tracking temps (via nanocom) during the last, super hot week here in Canberra. It's maxed out at 105 but usually sits around 90 +\- 5 deg. I did note a max of 174
(174 Doesn't sound right?
) after one short trip but wasn't recording so I can't see the reading either side and have regarded that as an outlier. Haven't seen it again though. Makes me suspect the sensor perhaps?
The 'different' fan noise has been more generally apparent in the last few weeks
(Hot ambient?) and yesterday morning it was making the noise straight after start up.
(Normal) Which makes me think fan unit is stuffed.
On arriving home yesterday (40 deg ambient), I observed the motion of the fan when shutting down and it stopped with a judder with the engine - it seemed 'easy' to move by hand straight afterward but seeing that makes me think it's pretty well engaged. Just started and shut down this morning and it did the same thing. I did this check last week and I'm pretty sure it spun for a while afterward - does this mean the fan unit is essentially 'broken'?
More generally, the truck has been well maintained it's whole life, with regular changing of the coolant (OAT); things are clean and water/coolant tight; 130k kms so I'm thinking it's likely not the radiator or pump.
If you've made it to the end - thanks! Any bright ideas? I could just swap out the fan, thermostat, radiator, sensor and waterpump but it would be wasteful if it's just one thing. What to do?
cheers,
bidds
Master
Originally Posted by bidds
Hi there,
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