up to no good
Join Date: Jan 2012
Location: Brockville, Ontario
Strange whine under the hood
Recently my truck's been making a strange whining/whistling noise when it's running. It's more pronounced than turbo whistle, but it's very intermittent. Not intermittent like a wheel bearing creak-creak-creaking, just that in comes and goes unpredictably (though more so at idle). It always starts off low and finishes at a higher pitch then just cuts out and makes no strange noises at all like nothing is wrong.
If I'm just idling and it starts to whine I can sometimes get it to "wind up" and stop by goosing the throttle, but then it just comes back again a few seconds later. It makes the same sound cruising at 100kph also, it will start to whine, then speed up and increase pitch, then just cut out. No engine RPM change or speed change at all.
It started doing this back at the beginning of April, but I changed the oil and that seemed to cure it. I drove the truck daily through to the end of june, then it sat for a while undergoing some serious drive-line and running gear repairs, got it back on the road in late august and now the whine is starting again.
I'm still new at diagnosing things like this, but if it were inside the engine then it seems to me the noise would me far more constant and fluctuate with every RPM change. And there seems to be no loss in power. And since new oil "fixed" it then it's got to be something that gets engine oil. I'm not sure how the vacuum system works, but does the vacuum pump get oil from the engine?
If anyone has dealt with this before I'd like to hear about it.
1996 F250 XLT, 4x4, 5 speed, LuK clutch, scsb, manual hub conversion, 265/75R16 Wrangler Territories, Tymar intake
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