I noticed when I got my '92 pickup that there is kind of an exhaust type of sound that is really noticeable only on acceleration, but it sounds like it is coming from right behind the dash, like right behind the gauges or just underneath the dash.

I have searched all over and cannot find any exhaust leaks in the engine bay. I thought that possibly the crossover was leaking or the connections where it connects to the driver side exhaust manifold, but I can't seem to hear anything when it's in neutral and I am revving up the engine.

I only hear it in gear while driving and it is pretty loud in the cab, sounds kind of like an exhaust manifold leaking, but I can't put my finger on it. Kind of like a loud ticking.

Are the 3VZE's known to be loud at all? I don't remember my '91 4Runner 3VZE being this loud or having this exhaust sound from the engine. But then again it was shot and had the big block lub and crappy idle.

This doesn't even sound like it's from underneath, it sound like it's coming straight from behind the dash, which is why I was thinking the crossover pipe.

Any thoughts? Any know issues?

Thanks.

 

There is a seal in the firewall for the steering column/shaft right where you suspect the noise is coming from. That seal is torn on my truck resulting in more engine noise in the cab.

 

It's normal. It's your clutch fan spinning. I was freaking out at first too. It's normal but like Wrench said you can fix your firewall

 

I'll take a look under there and see if that seal is torn. It sounds like an old jeep, chugging down the street, although I don't think it sounds like that outside of the cab. When I open the door while going down the road and press the gas, I can't hear it, but when the door is closed it sounds like chugging coming from behind the dash, like an old UPS truck or something, hahaha.

I'm not sure it's the fan, I have heard how it sounds when the fan clutch locks up and starts to whine and it's not like that, it's definitely an exhaust type ticking/chugging.

I was going to run some Seafoam through it (brake booster line) and see if I see any smoke coming out in the engine bay anywhere, seems like and easy way to see a leak.

I was also thinking if it could be intake noise? Doesn't the 3VZE have a know loud intake? Would that make a ticking/chugging sound like this?

Doesn't affect performace at all, just sounds crappy.

 

I have a manifold donut leaking on my truck...only sounds under load; it's been doing it for 35,000 miles. I'll eventually replace it....

 

Have the same exact problem. Did the seafoam last night and the crossover donut?? gasket is bad. All kinds of smoke poured out right at the flanges.

Im thinking its part number 256287 from rockauto.

 

There is a plastic box at the right rear top of the engine that has 4 screws holding the cover on and the screws become loose or fall out all together and make this noise usually when it is first started and then goes away, my wifes 4 runner does this and is missing 3 of the 4 screws. I can take a pic of it later, my wife has it at work right now. Just something else you can check.

 

Nah, this is definitely an exhaust noise, just not sure if it's a leak or just normal exhaust noise coming through and sounding louder.

I have also noticed that when I first start in the morning and it's running real rich, warming up, if I turn the fan on at all I will smell exhaust in the cab, that's what leads me to believe it's a leak, although once it's warmed up I never get any smell but the noise always stays. I can never hear it in Neutral while revving the engine, it is only under load/acceleration.

 

Upon warming the engine, it burns exhaust correctly, thus reducing the "smell" although the gases are still there, but less prevelant. So dont think that once your engine warms up and you have the fan on, that there is no exhaust being pumped inside the cab. Falling asleep at the wheel is never a good thing. Your displacing O2 with CO2.


As a side note, I checked my crossover gaskets and all 6 nuts were loose. Tightened them up and am hoping thats the end of my crossover leak. I did some searching and this is the correct part number FEL-PRO Part # 23561 for the 3.0

James Woods, where are the pictures of the plastic box your talking about?

 

Sorry, my dad stopped by and I completely forgot about it. My wife is gone with the car again but I found a pic of it online. It does sound like an exhaust leak right at the dash, its real loud and then just goes away I guess it is the PAIR reed valve that I am talking about.
https://www.yotatech.com/forums/f116...d-valve-95842/

 

The 3.0 is a relatively "loud" engine even off the factory floor. Combined with the valve ticking, and the semi low rumbling exhaust.