Hey folks, I searched around allover the interwebz & this forum before posting. Any advice you can give would be helpful.

I have a 2006 V6 4.0L 4runner SR5 that's making a perpetual loud gurgling engine noise almost how a diesel engine sounds. The engine seems to perform just fine, but the noise doesn't sound good. There's no loud knocking or ugly mechanical grinding or anything like that.

I'm sure you've heard of the floods down here in SC -- well I drove it briefly through a flooded street last week and I'm wondering if the engine may be damaged from the water. I don't remember that the water was too high--maybe up to the bumper but certainly no higher than the floor boards. Definitely nowhere near over the hood or anything like that. I drove it straight through a few spots of standing water, maybe 2-3 times for a 1/8 mile at the longest, and then for another 10 miles or so on high ground. I drove it a few more times after, each time for a couple miles on high ground, and everything seemed fine--the brakes squealed at first but that went away quickly. But starting today now the engine is making that noise. No other symptoms--still seems to drive fine. It hasn't locked up or anything like that, and again there are no knocking or grinding sounds. No abnormal smells under the hood. All the exterior lights and interior electronics work ok. The car sat out in heavy rain for days after but it was never submerged or anything--standing water around the tires never got higher than maybe 2-3 inches. I called a mechanic and he warned me I may have done serious damage when I drove through the water. But what confuses me is that it never stalled, it continues to drive okay, and there are no other symptoms that I can find.

Anyone have any thoughts? Could the noise and the water event just be a coincidence? Could the water have caused something else besides getting into the intake (which I assume would've resulted in a hydrolock). Just trying to get informed & prepare. Thanks in advance.

Its hard to diagnose sounds, but have you considered a bearings one of your pulleys? How fast were you going when you went through the water? Based on what you describe it doesn't sound like water made it into your engine. Usually water will either lock one up or burn off if it makes it into the combustion chamber and doesn't hydrolock. Now in the unlikely event oil made it into your crankcase, bad noises would be possible. If you went through deep water and you weren't prepped, check your fluids - trans, oil, diffs, tcase. If any look milky then water has gotten in. Flush and replace fluid in that case? I suspect your noise is related to a bearing failing due to water logging.

Good thinking...thanks! It could be a pulley, I'll check them out. I guess to find if it's a bearing problem, I'm not just looking for a wobbling pulley but I'll have to remove the each pulley and inspect for wetness?

I was moving slow but steady, maybe 7-10 mph, never came to a stop.

Do you have water in your oil?

Did you check your air filter? Is it wet?

Check your vacuum lines to see if any are loose or came off?

Does your coolant look ok?

Can you record a video of the sound?

Does your exhost smell/look normal?

Any check engine light?

I agree with above, check to see if you have water in the motor oil and I seriously doubt that you have water intrusion. Nor will there be any bearings that are starting to fail right after your water crossing unless you have water. Also, check the ATF also for water intrusion. This is not a Land Rover for crying out loud

I'm more inclined to think you may have a pulley/belt issue that's now unhappy. Nevertheless, swap you engine and ATF fluids just the same.