Hi, all. New guy from Michigan here. I have been reading through some of the threads to help me with some of my issues but thought I should sign up because I have some more questions I have not been able to find.
I recently purchased a 1989 F250 XLT Lariat with a 5.8 EFI engine from my wife's grandfather. I have replaced the exhaust manifolds and removed all of the emission stuff. Since I purchased it, though, there has been a squealing coming from under the hood that I only hear when I get begin up to speed (between 35-55) and it will continue as I am driving down the road. I have replaced the tensioner pulley and removed the smog pump pulley and put a smaller belt on it to bypass it, but the squealing continues. To make sure it wasn't something in my drive train, I removed the belt and took it for a quick spin down the road. It didn't make a sound. I put the belt back on and took the same trip and it squealed the whole time. When I take the belt off to spin the pulleys I cannot tell which one is causing the problem. They all spin freely except for the steering pump pulley, which turns with a little difficulty. Could it possibly be the power steering pump? When I was replacing the exhaust manifolds I noticed that the cap was missing from the power steering reservoir. For how long is anyone's guess. I really need help getting this narrowed down. Has anyone had this problem or maybe know what I am dealing with? Thanks in advance.

 

Yes I have. If it doesn't squeal without a belt and all your pulleys sound good, that points to the belt itself. It's mostly likely frayed, cracked, etc. Replace your belt and that ought to stop it. I've had it happen to me on another truck and it was exact symptoms you describe.

 

I appreciate your input and that is the first thing I thought as well. But after putting two new belts on it now I have to think it is something else. BTW, I took a look at your build thread, Truck Guy, and I have to say I am impressed with the amount of gumption someone your age has. Good job.

 

Hi 89XLT,

I totally understand the frustration of not being able to find a noise. Awhile back my truck would make a horrifying squeal when I got up to highway speeds. I was looking around under the hood and found that my fan clutch had locked up and then freed itself, which destroyed it internally causing the terrible noise. Have you spun your fan lately? Does it turn freely or require a bit of force? Might sound simple but it's worth a shot to check.

As for the power steering pump, that's sounding like a suspect. I know my power steering pump is worn out, but it only makes a whining noise, especially when turning the wheel. We might have different definitions of 'squealing', who knows?

Have you done the "spray test" on all of the pulleys? Some might only squeal when wet or dry and this can determine different things. If you look up some videos on Youtube on this subject you can learn what each pulley squealing means, different sounds to look for, and what it means if the squeal while wet or dry. I'm not exactly sure what to search to find those videos but I know they're out there on Youtube.

Keep us updated!

 

1995 F150,

Thanks for the idea. I went to You Tune like you suggested and looked at spray tests. While that would not have worked for what I am dealing with, it did point me to some other videos to watch. What I ended up doing was having my son get in the truck, step on the brake, put it in drive, and step on the gas so that the engine was under load (that was the only time I could hear the noise). When he did that I heard a horrible grinding sound coming from the alternator. So I pulled it off tonight and will swap it out tomorrow and see if that fixes the problem. Thanks again for pointing me in that direction.

 

No problem man, glad you could narrow it down. Let me know if the alternator works for you