I has been quite cold in my area lately. Buy cold, I mean like 0 or a few degrees below. We also had some snow which ahs made it a requirement to drive my 4WD Ford truck with the 4.6L engine. This is a 1997 Ford F-150 light duty which is the oddball with the 7 lug wheels among others. It is 4WD with a manual transmission. The truck has close to 300k on it and I was told it had a used engine installed when I bought the truck but have never been able to verify this. The engine runs well without odd noises or clanks and doesn’t burn or use oil. I have the O’Reilly brand 5W30 synthetic oil in the engine.
There has been a strange whine that comes from the engine at startup in these very cold temps. This only lasts a few short seconds and quickly goes away. I have the manual transmission in neutral so I figure it is engine related and not the transmission. It sounds like a gear noise or whine so I am assuming maybe the oil is too thick to get through the oil pump, timing chain, or similar.
This only happens at cold starts when it is VERY cold outside but I wanted to make sure this wasn’t a sign of impending failure. The truck runs well otherwise and I would gladly replace the oil pump if it were going out. I was also thinking about switching to a 0W30 as the truck is mostly used in the winter anyway if the oil not being thick enough is a possibility.
I have a Mustang with the 4.6L and mine does the same thing when the temps are in in the single digits, I used 5W20 synthetic. I’m pretty sure the whining in my case is from the power steering pump. The noise goes away after a few minutes.
My noise goes away after like 2-4 seconds. I guess the power steering pump is a possibility. This was replaced not all that long ago so maybe this is the difference between a few seconds and a few minutes. I have heard that whine from power steering pumps before and this might be related but sounds different. I might try to have someone start the truck while I listen to the engine compartment.
I agree with the posters here, power steering pump. To test it, as soon as the truck is started and you hear the whine, turn the steering wheel. If the whine gets louder, bingo, power steering pump. Don’t worry much about it. The fluid is much thicker when its really cold and doesn’t pump as well. You might consider changing it if you’ve never done it. Almost no one ever does until they leak or fail.
I know I changed the fluid a couple years ago. I had to take the belt off to move the AC compressor off to the side so I could replace the cam or crank position sensor. When I released the tension on the belt, fluid began pouring out of the power steering pump at the shaft so I guess it was worn and on its last legs. Either way, the system was purged of the old fluid and replaced.
I am probably just not going to worry about the noise. It goes away very quickly and only happens in extreme cold so it is probably not the end of the world.