I know there have been a few threads on this lately but my '97 (180,000k) is making a noise different from those described already. A couple months ago I noticed a slight rattle but just thought it was something behind my dash. It's gotten to the point that I am now concerned about something serious. I popped the hood the other day and started to investigate. Its sounds like it's up high right underneath my intake manifold. It's a little bit of a diesel-ish sound and it oscillates a little when idling. It's pretty subtle but it's getting worse. I notice the noise more inside my car than out. I dont know if I'm having an issue with valves and lifters or what the deal is. The performance of my car is thus far unaffected but if this is a harbinger for something serious I want to fix it before it becomes a problem.

your thoughts?

 

Hey bro,
My 2001 4Runner is doing the same thing. I've messed around with the dash with no luck and I think it is something ahead of the firewall myself. Did you have any other luck on running this down?

Mine is worse when it is cold and increases when driving over the potholes in DC.

Thanks!

DS

 

does it happen when you're sitting still? does it increase with rpm? make a video and post it.

 

I think we have the same noise. I don't think mine starts until the engine is warmed up. If you rev the engine while sitting still in neutral do you still get the noise?

 

A little more info would help, I'm on mobil so I can't see your specs if they are listed.. is it 5speed or auto, and +1 for the video.

 

(Double post)

 

10 bucks says your water pump is crying.

 

That's my bet too. Mine rattled, got worse, and then seized on my way home from work. I put about 100 miles on it from when it started to when it seized. I just thought it was something bouncing around my intake manifold. It was a weird rattle, so I didn't know what to do. You can see the carnage in my Profile thread in my sig line. My aftermarket water pump (Autozone) lasted about 40,000 miles before it gave up. My sound was plasticky bouncing, sounding like something in the intake. Get it checked!

 

I recently bought a 97 4runner that seems to have the same noise. There is no loss of power or performance, and the gas mileage is 16.5-17 city, so pretty standard. So, it seems that water pump is a general consensus, but do you think a valve adjustment might be another option? I have posted a video I took with my phone to try and illustrate the slight loose/rattle-y noise I hear. Any insight is appreciated!

 

Haven't seen this thread in a while!

I don't hear rattling in your video, at least not like mine was. To me your motor sounds like a diesel, which could be valves, but I'd take it to an exhaust shop and see if there's an exhaust leak. That's what it sounds like to me. Maybe someone else can hear the rattling better than I can though.

As far as adjusting the valves, it's possible, and I'd bet it would help a little bit, but unless you bought your rig with over 250,000 miles they're probably close enough to do the job. Most of the time it's a tough job to adjust these valves, as they're shimmed, not sprung. I find my driving habits kill my mileage more than anything now..

 

Mine sounds like that. when you first crank it you don't really hear it but after about 5 min you hear it. A Toyota tech that I know listened to it and said it sounds like loose valves. He said don't worry to much about it. Mine is a 96 with 199K

 

How many miles on it? Could be valves needing adjustment. How is the oil? When was the timing belt last changed?

 

Thank you, everyone, for watching my video and thanks for the prompt replies! Since the thread was so old I wasn't sure anyone would be around. Sorry I forgot to tell the mileage. It has 187,500 on it (got it at 186,300 and it's been running fantastically so far).

Hi 4biker, thanks for your reply! I agree. The noise is subtle and isn't really a rattle, but has a diesel-ish type sound. My dad has an almost identical 96 with 245k+ on it with no noise. I'll look into having the exhaust checked out as well. The place I took it to said that it could possibly be the valves, and gave me a diagram illustrating and explaining the valve clearances. They didn't think it was something to worry too much about, since there's no loss of power, etc. and suggested that for my next oil change I use a thicker oil (10W-30), and an additive (I was thinking Auto-RX).

Thanks for your reply, breugel! I was told pretty much the same thing. I think I'm gonna just let it go for now until I just can't stand the noise or it blows up.

Hi rworegon, thanks for your reply! As far as the oil, my last change put 5W-30 Havoline in it. It was suggested by the shop I took it to yesterday that I put a thicker oil to compensate a little for the possible loose valves (and hot ambient temperatures of AZ) and an additive. The timing belt was changed at around 160k, about 4 and a half years ago.

 

Havoline, while good oil and used to be great before being bought out by Chevron, is now a thin oil, really thin across all grades. Don't ask me why it was changed.

Try using an oil such as Mobil Super High Mileage 10w-30 (fine for AZ) and see if that helps those valves. Forgo using the Auto RX, Lucas, etc.

 

Mine had a rattle at idle that I isolated with a stethoscope, it was the fake waterpump (fan bracket). Replaced it and no more rattle.