X13

Greetings all

1993 xtra cab 3.0 128,000+ miles. My troubleshooting skills blow and I while I can find a ton of stuff here on the site about noise. I’ve had no luck finding information about this. So here goes. The noise is sort of a growl, it would almost sound cool if it was meant to sound this way. It’s loud, and present all the time except when I give it gas.

So basically I start the truck and there is this loud growling noise, I put it in gear step on the gas and the noise almost completely goes away, I can hear it faintly, but nothing like at idle. If I’m coasting to a stop in neutral or engine breaking or shifting or whatever, the noise can be heard. But as soon as I put a little pressure on the gas it goes away.

It sounds to me like it’s coming from the engine compartment near the firewall. But to be honest I can’t tell if it’s up high or down low, it’s too loud. At idle it almost sounds like exhaust, but while engine braking it also has a bit more of a grinding sound to it. Hopefully that doesn’t confuse people reading this. For what it’s worth, the truck feels strong. Starts right up, and runs without any real complaint.

Thanks in advance.

Radyota

Does it sound a little like a jake brake on a semi when you downshift? Mine does - - and I made it sound that way. The noise isn't harmful, just something to do with the crankcase ventilation system. Check all of the air hoses/connections on and around the airbox/filter area. If one is leaking, it could be the one that's causing the noise. I eliminated the 2 little plastic boxes bolted on the air filter housing, and hooked the 1 3/4" hose directly to the airbox. That's the one that pulses air from a reed valve box on the passenger side of the engine. The pulses are amplified in the filter chamber, causing the "growling" noise. Just make sure your air hoses aren't leaking and making the engine run lean, because that would be bad. By the way, welcome to YotaTech!

regularguy412

Thrust bearing?

Mike in AR

X13

Thanks for the ideas and the welcome. Hopefully this is something that ends up being an easy fix. Thanks again.

wrenchmonster

How about a run of the mill exhaust leak? Check around all exhaust components real carefully for cracks, leaks, black carbon trails. Break out a mirror and remove heat shields if necessary. Have a buddy hold a block of wood over the exhaust pipe to build exhaust pressure while at idle. Does the noise change? This may also aide you in finding an exhaust leak if you have one. Don't hold the block on too long though. Good luck.

DyeBoi

I agree with Radyota, I have the same issue. The noise is a sorta burbling noise, present at start-up, but with some gas, goes away, but comes back when you're slowing down again to stop. I removed my whole intake box and routed it to a "homemade" instake tube, so its loud. II attribute mine to the reed valve and the removal of all the silencer boxes that were connected to the intake box.
Have you modified your intake system at all?