4.0l ohv making strange noises

[bigtruck94]

I was out deer hunting a couple weeks ago. Over the years, I have took my ranger back in the rough sandhills a lot and have no problems. Well I was out scouting for a deer and when I returned back to the farm, I noticed a little whistle sound. It literally sounded like a turbo spooling. I went to grab my diagnostic tool and plugged it in and it said it was my charging system. I was trying to find where the whistle was coming from and it sounded like it was from my alternator. Now this is when things get a little weird. It stops doing it for the past 4 days then it does the whistle again. It's funny, the alternator is charging fine and the battery level is at normal.

Than today, I was on my way to school and it starts making the whistle, this time it sounded much more aggressive. I really don't know whats going on with it. It starts fine in the cold morning.

I must of bumped something inside out in the hills. I was going quite rough out there with it. If anyone knows about this, please help me out! I need this pickup more than ever! I hate it to quit on me!

 

[RonD]

Bearing in alternator is probably going out, or another belt driven pulley bearing.
With engine idling turn on all the lights, fan blower to high and anything else electric, see if that starts the noise, rev engine a few times as well, then turn electrics off and see if noise goes away.
Under load is often when bearing noise will first be noticed, so it can come and go but it will get worse over time no matter what.

Remove belt and spin pulleys by hand, see if any feel loose or drag at a certain spot.
Don't forget water pump and the belt tensioner.
Could even be the fan clutch although that is usually seen as a rise in normal temp or a vibration at certain RPMs.

You can start a cold engine without the belt and run it for a few minutes, battery light will come on, just to confirm if it is a pulley bearing that's making the noise, so if whistling is steady now with belt and no whistle without belt then it is a pulley.

My '94 4.0l doesn't have a Cam Position sensor in the distributor hole, but I think some did, these can make a high pitched squealing when they are going bad, and if they do break while driving the oil pump stops, so very bad news if that is left unrepaired.

Also check the air plenum and air filter, whistling noise could be from air flow, long shot but still a shot

 

[bigtruck94]

Bearing in alternator is probably going out, or another belt driven pulley bearing.
With engine idling turn on all the lights, fan blower to high and anything else electric, see if that starts the noise, rev engine a few times as well, then turn electrics off and see if noise goes away.
Under load is often when bearing noise will first be noticed, so it can come and go but it will get worse over time no matter what.

Remove belt and spin pulleys by hand, see if any feel loose or drag at a certain spot.
Don't forget water pump and the belt tensioner.
Could even be the fan clutch although that is usually seen as a rise in normal temp or a vibration at certain RPMs.

You can start a cold engine without the belt and run it for a few minutes, battery light will come on, just to confirm if it is a pulley bearing that's making the noise, so if whistling is steady now with belt and no whistle without belt then it is a pulley.

My '94 4.0l doesn't have a Cam Position sensor in the distributor hole, but I think some did, these can make a high pitched squealing when they are going bad, and if they do break while driving the oil pump stops, so very bad news if that is left unrepaired.

Also check the air plenum and air filter, whistling noise could be from air flow, long shot but still a shot

I think only the rangers in California have the Cam position sensor because of emissions. But I will give those a shot!

 

[Road Angels]

My fan clutch made a similiar type of noise at first, havent fixed it now its sounds like a bird chipping, and the engine runs cold, cause the thing takes a lot of push on the blade to turn it when cold, Yea Iam cheap I will wait till it flys off the h2o shaft

 

[bigtruck94]

Well I took me alternator out and it is showing it's wear. Than i turned my idler pulley and it was not spinning very freely. So think both alternator and idler pulley is going to get replaced.

 

[bigtruck94]

Problem solved! Turns out the alternator is perfectly fine and instead of spending 150 bucks for a new one, I spent it on an idler pulley only paying 30 bucks!

The bearing inside the idler pulley was very stiff and it didn't spin freely, resulting in a worn out bearing. Thanks guys! I learn more about this pickup as time goes by and I like it! But unfortunately, I won't be keeping this pickup for long. Maybe by next year, I will possibly be getting a 7.3 stroker that is a little more reliable for me to tow the trailers and get to college.

 

[TrexMex]

Problem solved! Turns out the alternator is perfectly fine and instead of spending 150 bucks for a new one, I spent it on an idler pulley only paying 30 bucks!

The bearing inside the idler pulley was very stiff and it didn't spin freely, resulting in a worn out bearing. Thanks guys! I learn more about this pickup as time goes by and I like it! But unfortunately, I won't be keeping this pickup for long. Maybe by next year, I will possibly be getting a 7.3 stroker that is a little more reliable for me to tow the trailers and get to college.

Just went through the same process with my pulleys; idler pulley was making pretty much the same sound you described. Glad you got it worked out!

An F250 with a cummins in it, that would be reliability...

 

[bigtruck94]

Just went through the same process with my pulleys; idler pulley was making pretty much the same sound you described. Glad you got it worked out!

An F250 with a cummins in it, that would be reliability...

Cummins is a great motor, I just don't know them as much as the powerstrokes