1999 Expedition 5.4L Triton - Help needed!

[Shelby_]

Hey y’all! I’m new on this forum because I’m trying to figure out what’s going on with my Expedition. I know this is a long post but I’m trying to provide all the info I have to make this an efficient process if anyone can help.

Some info on it: it’s a 1999 Eddie Bauer 5.4L Triton with 126k miles. I bought it from someone on Friday and it’s a one owner, no accidents, garage kept, and honestly the interior is in remarkable condition considering the age and having leather. The A/C works well and it drives great. I believe a new starter was put on it by the previous owner’s family mechanic, and his shop is where I picked up the vehicle. The only things that are “wrong” with it is it needs new shocks and tires, the linkage in the gear shift is loose, and the weird sound I’m describing below.

Here’s my issue… it’s making this weird noise and it’s hard to describe but I’m gonna do my best. The sound is almost like a rumbling/grinding type of noise. I’ve looked up a million different things and I can’t find anything online so now I’m here. It’s coming from the front passenger side, somewhere behind the glove box. I don’t know if it’s coming from the engine bay or inside the actual cabin.

The sound Has happened many times since Friday when I got it. It happens sometimes when I put the vehicle in park, a few times when I am in moving in Reverse, and it also happens when I start the truck from a warm (when sitting for an hour or more) or cold start. It also happened when I was in Park idling and the weirdest one - when it was turned OFF. The time when it was turned off, it had been off for at least 30 minutes. I was cleaning the steering wheel and wiggled it a little and then it made the noise. I wiggled the wheel again and it stopped. The sound always lasts for about 5-6 seconds.

I have no idea what it is. I’ve tried to experiment with a few things, like starting up with all the A/C off, turning off the rear A/C only when I hear it, turning off all the A/C, putting it in gear, and wiggling the steering wheel. None of this changes anything. I don’t know if this is related, but I also noticed the rear A/C makes a slight hissing sound and the heat doesn’t get super hot in the back, just kinda warm. In the front, if it’s blowing at the coldest temperature and I start to turn up the temperature, it’ll stop blowing all together once I start getting in the hotter range and it’s almost as if I turned off the A/C but I can still hear a blowing sound, it’s just not coming from the vents.

I hope someone can help because I don’t know what this is. I have no idea. Part of me thinks it’s fuel pump related, another part thinks it’s something with the A/C system. Thank you in advance and thank you for reading all this, I know it’s a lot.

 

[Expd830]

Have you checked the starter, online it relates to this problem

 

[Shelby_]

Have you checked the starter, online it relates to this problem

I have not, because the mechanic was said to have replaced it. I also don’t have any problems starting the vehicle. It doesn’t make the grinding sound every time, only sometimes, and it’s happened with the vehicle being completely turned off, while idling in Park, and the other situations I mentioned that kind of just lead to me thinking it’s something else.

 

[Yupster Dog]

while idling in Park, and the other situations I mentioned that kind of just lead to me thinking it’s something else.

Could be your fan clutch. Mine went bad and i never noticed because i was looking for something not working but it was still spinning (from kinetic force) and i didn't think anyting about it until one time it was off and i turned the fan. The whole backside of the fan was wallered out and it was just sitting on the mount for the fan clutch.

It eventually sounded like rocks in a tin can rolling around.

 

[Shelby_]

Could be your fan clutch. Mine went bad and i never noticed because i was looking for something not working but it was still spinning (from kinetic force) and i didn't think anyting about it until one time it was off and i turned the fan. The whole backside of the fan was wallered out and it was just sitting on the mount for the fan clutch.

It eventually sounded like rocks in a tin can rolling around.

Thank you! I’ll definitely look into this.

It’s been throwing me for a loop because everything runs totally fine, it just makes this terrible sound at the most random times.

I did notice that if I turn the key to only start the battery, it’ll make the sound each time I do this. That’s why I assumed fuel pump but I’ll do some research on the fan clutch now.

 

[Trainmaster]

If it's doing this when the engine hasn't been running at all (as Yupster suggested) the only thing left is the fan motor, blender door motor or maybe a chattering relay in the fuse box.

Aside from that it sure sounds like the fan to me.

 

[Shelby_]

If it's doing this when the engine hasn't been running at all (as Yupster suggested) the only thing left is the fan motor, blender door motor or maybe a chattering relay in the fuse box.

Aside from that it sure sounds like the fan to me.

I was thinking about how I could explain it better because it’s a strange situation, but I think I need to mention — it usually doesn’t do it with the engine off and it was only one time that it did. Otherwise, it happens when I start the engine from a cold or warm start (by “warm” I mean it’s been sitting for an hour or more but not long enough to be “cold”), when I put it in Park after driving around, when I turn the key forward (which in my mind would be engaging the fuel pump and battery), or when I put it in reverse.

Only twice have I had outliers that didn’t fall within those specific times I mentioned above, and that’s the one time it did it when the engine was off and had been sitting for almost an hour (30-45 mins) and the second time when I was in Park just idling for about 10 minutes.

But It’s not only when the fan is running, which is why I’m unsure about the fan clutch being the cause. The fan has never come on at a cold start. No check engine light or codes are coming up either. I’m just beyond lost with this lol. I’ll look into the fuse box relay and blender though, thanks!

 

[jr1under]

Assuming you have air shocks, could the noise be coming from the air suspension compressor?

Your description is kinda what mine sounded like until (thanks to this forum), I replaced the vibration isolator bushings. There was nothing wrong with the compressor but the bushings were toast and probably had been for years. It's way quieter now.

 

[Shelby_]

Assuming you have air shocks, could the noise be coming from the air suspension compressor?

Your description is kinda what mine sounded like until (thanks to this forum), I replaced the vibration isolator bushings. There was nothing wrong with the compressor but the bushings were toast and probably had been for years. It's way quieter now.

I don’t believe I have air shocks. It also doesn’t happen all the time. Like it’s not only when I turn the air on/off or only when I turn, put it in gear, etc. that’s why I’m struggling to figure it out because it only happens on start up, and some other times randomly. But it disappears after a few seconds and stays gone

 

[jr1under]

If you don't have air shocks then this is definitely not the problem! However, every symptom you've described fits with how the air suspension operates and sounds.

Attached is a picture of mine. If yours doesn't have a compressor in the same spot, I'll bow out of the conversation because that's all I got.

 

[rjrodney]

Not too sure about the sound yet but your shift linkage is super easy to tighten up - one bolt. Google can solve that one. Right behind your glove box is the heater core and AC condenser. It doesn’t sound like water squeezing through a blocked core does it? How’s the heater??

 

[Mikeyfive]

From your description I'm betting you found the compressor under the washer fluid reservoir. Since it comes on when you start up, or start and go. It's the self leveling air suspension. By the sound of it, you may have a slight leak. Bubble test all connections, and around the shock skirt for leaks. Bully for jr1under! He called it correct!

 

[Saxxist]

Since you have a 1999 Exp EB, you probably have the 4x4 air-ride shocks. Mine (with 190k miles) makes a similar sound when the air-ride is leveling the cabin.

 

[Brian Meek]

Come on, @Shelby_ - when you call upon the wisdom of the forums and receive help, post a summary. Or at least an acknowledgement of folks' efforts to help!

By now you're wondering if your air suspension has a leak. My 2001 EB 4x4's air suspension finally failed and the truck sank very low in back... Opted for a conversion kit to standard shocks all around. I'd almost forgotten about the compressor noise I used to hear.