Mystery Squeak?

[eric_rosenwald]

First of all... I'm not getting a check engine light.

I'm hearing what sounds like a low-pitched squeak when going about 60 mph. It also feels a little rough. It sounds like a belt. I've done a visual check of all of the belts and felt them -- They didn't seem to be bad.

I bought this 4Runner a few weeks ago, and the mechanic I take it to said it was in great condition (he did a thorough inspection). The previous owners never took it off road. I'm in the process of breaking it in, finding any weaknesses or problems. I want to take it off road on the weekends, and do a road trip this summer, so I want to make sure it'll be OK. I got a P0420 code the other day that turned out to be nothing. I think it was related to using gas that had a few impurities (I refueled from a suspect gas can), or that the never-before-seen shaking of off-road driving shook up some old sediments in the tank. I put some sea-foam in it, and it performed well.

This squeaking problem has happened twice, starting about 10 miles away from my final destination. It happens at about 175 miles traveled for the day -- about half of that off-road. I did about 250 miles the other day on the freeway without this problem. The belts seem ok... Any suggestions? It would be nice to have a check engine light to help diagnose this!

 

[jgue467]

You could try some belt dressing or bar soap to find out if its the belts or not. But belts usually squeak on moderate to hard acceleration not so much at speed.

The p0420 has a list from the FSM that includes:

1) Gas leakage on exhaust system

2) A/F sensor (bank 1 sensor 1)
3)
Heated oxygen sensor (bank 1 sensor 2) and/or

4) Three-way catalytic converter

Its not nothing, its one or more of these things. When you clear the code the ECU will want the vehicle to travel 50 miles at moderate to high speed before it decides if the issue still exists - so just because it didn't return immediately doesn't mean it won't. Despite this, Luck! :banana:

 

[Mynameistommy510]

The squeak could be coming from one of your pulleys. Try some liquid lubricant on them individually to see if you can eliminate the problem. The AC idler pulley gets loud quite often after offroading from dirt build up.

 

[eric_rosenwald]

I drove 30 miles on Death Valley back roads, and on the freeway about 60. The check engine light never came back on. That included some serious uphill stretches.

Do you think that P0420 code is related to the squeak? My girlfriend described it another way.. Kind of a hissing or gurgling sound. It was evident primarily going uphill on the freeway. It just gradually got worse, only happens with my foot on the gas pedal. It goes away as soon as I get onto streets.

 

[eric_rosenwald]

The squeak could be coming from one of your pulleys. Try some liquid lubricant on them individually to see if you can eliminate the problem. The AC idler pulley gets loud quite often after offroading from dirt build up.

I've been suspicious of this. I haven't had the car very long, so I don't have much experience with this one... But the reality is that it only ever happened after a 60-mile off road+20mile on road day, and a 100mile on road + 40mi off road day (yesterday). But it also came back after being on the freeway for 20 miles this morning on the freeway only. It made it without a sound after a 175mile all-freeway day a week ago. So it's hard to just isolate the variables. Maybe it was going to happen anyway? I had driven it on the freeway for a 100 mile day two weeks ago without a problem... My gut still tells me that this is all a result of off road use. The p0420 may have just come on because I gave it potentially impure, high h2O gas/shook up old tank sediments. Hopefully this is ALL just a result of being broken in, essentially. A city only, 2wd-use only 14 year old car being taken 4-wheeling on dusty roads for the first time in its life.

 

[eric_rosenwald]

The squeak could be coming from one of your pulleys. Try some liquid lubricant on them individually to see if you can eliminate the problem. The AC idler pulley gets loud quite often after offroading from dirt build up.

The sound keeps consistently coming back after driving on the highway for about 20 miles. It only makes a sound when my foot is on the accelerator -- even slightly on it. Sometimes, there's a new sound -- more of a classic screeching belt sound. It comes up only briefly, as soon as pull my foot completely off the accelerator. It doesn't last long at all.

I'm not sure where all of the pulleys are, so I'll take it in and have them put a little bit of lubricant on them. Any idea why the belt sound comes on like that? It's an unusual set of driving circumstances for a belt to make a sound...

 

[slapdappy]

rpm or speed dependent?
gurgling or hissing? Does anyone know if it could be the brake booster pump or some other brake system related item. Can master cylinders make sounds if the seals start to fail?
a/c compressor pulley? Pulleys are the wheels the belts spin around. They drive the power steering pump, the ac compressor, the alternator.
Belts too tight or too loose? or some of each?
noise def from engine, not transmission?

I, a non mechanic, vote power steering pump or a/c compressor.

 

[BlazeRunner]

Check driveshaft for play in U-joints just to eliminate possibilities. U-joints can squeak and make all kinds of noises, especially if they're going bad and get all heated up. They're under more stress when accelerating, so that's why I suspect.

 

[eric_rosenwald]

rpm or speed dependent?
gurgling or hissing? Does anyone know if it could be the brake booster pump or some other brake system related item. Can master cylinders make sounds if the seals start to fail?
a/c compressor pulley? Pulleys are the wheels the belts spin around. They drive the power steering pump, the ac compressor, the alternator.
Belts too tight or too loose? or some of each?
noise def from engine, not transmission?

I, a non mechanic, vote power steering pump or a/c compressor.

not RPM dependent. It only happens after about 20 miles of driving on the highway, so it is somewhat speed dependent. I just got the brakes checked out, and they're fine. However, I needed to replace the bushings on the rack and pinion. I doubt that will have anything to do with it, though.

Some people in this thread suggested that it could be that the AC idler pulley/belt needed a little bit of lube. So while I was getting the bushings fixed, I had them lube them up. I plan on driving on the highway about 40 miles tomorrow, so we'll see if that's it! My next check is if there's too much tension on the belts (if it's still making that sound).