Hme057

Hi, im new here and have been having a strange problem 01 4runner

Over the summer, i did a tune up and changed some fluids. I changed the tranny fluid, PS fluid, flushed radiator, cleaned TB and MAF sensor, changed plugs and wires, did ISR and deckplate mod, added tranny cooler and bypassed radiator cooler, changed fuel filter, bled brakes, put on new rotors and pads on front and rear brake shoes. I've owned my 4runner for 4 years now and other than changing the oil, didn't do anything else but after i did all this my car drove alot better and it was very surprising how off it had been before. After i did all the work i would be driving and come to a stop light and think my car had shut off because i couldn't feel it anymore and i was so used to it idling rough, so i was happy

However in the last 2 months or so, thats changed. My car has started vibrating when im idling again, but my rpms aren't moving, and i feel its not the engine causing the vibration. What's more, i hear this strange sucking noise , or like a fluid being pushed under pressure through something, coming from the front passenger's side toward the engine compartment from time to time, maybe 2 or 3 times in 30 minutes and its related to how the car idles. what happens is ill be driving and come to a stoplight and as i come to a complete stop my car begins to vibrate, and as time goes on the vibration gets worse and worse, then i hear a click and the sucking noise, and the vibration settles down, but doesn't go away. Its worse if i have the heat on.

Now when i driving, i can't feel any vibration, and even if i just give it the tiniest bit of gas it completely stops. I think it goes away if im just rolling, i can only feel it if i stop completely and from the moment i stop it get worse and worse untill the sucking noise happens. also i can hear the sucking noise from time to time even when im driving so its happening while moving or idle. I'm not sure what to think of it, and not sure why it just started happening all of a sudden after it had been driving and idling so well

idk if it could be related, but when i first start it up when its cold, the engine will idle at around 1,600 rpm and there's no vibration, but when it heats up it will go down to 600 rpm where it starts vibrating, and that started happening after cleaning the MAF and TB, not the vibration and noise, just the high start up rpms

rworegon

Can you narrow down where this sucking sound is coming from when the engine is running? Check all your vacuum hoses and intake hose for cracks and proper fit. A vacuum leak can cause the timing to go haywire causing weird sounds and vibrations due to the unmetered air. Sounds are really hard to diagnosis over the web.

BTW, welcome aboard. Make friends with the search function here.....must of the routine stuff has been covered many times.

Hme057

Thank you I've read alot of the tech writeup's here and they're all sooo helpful, and everyone here seems to know a ton about toyotas, so i figured id give it a shot!

its hard to really explain since it only happens after i warm it up from driving so from my position in the drivers seat it to the best of my ability to hear it, sounds like its coming from right behind the firewall just foward the glove compartment. I'm almost positive its not an air sound, sucking is probably not the best way to describe it. another way you could describe the sound is like a muffled hissing noise but my first inclination is some kind of fluid flowing or like steam being pushed through a vent or something. and i seem to remember it sounding like it also comes out of the air vents when it happens.

I know, its hard to explain and figure out sounds but i've never heard anything like it in anyone elses car before. I want to say maybe somethings wrong in the AC compressor because the vibration isn't like it was before. Before, i could tell the engine was running rough, and the rpms would flucuate abit but now the tach seems to be solidly planted at one rpm, around 600 or so, even when its vibrating. its like its coming from something else and i say AC because of the strange nature of the noise, its like freon flowing or something because right there in the engine compartment are where the pressure lines are running for the AC i think, but the AC is still cold. However the vibration does get worse when the AC is running, but it also gets worse when the heat is on so im not sure

I guess i should also say that no lights come on or anything and i've inspected the hoses after it started happening and didn't see any cracks or anything loose. The engine also runs perfectly other than this little problem. If im driving it accelerates great and i can't feel any vibration at all.

rworegon

Is your passenger floor board wet from a leaky heater core? So after the truck is warm and you are hearing this sound, could you leave it running in park and hop out and open the hood to take a look see?

Hme057

I thought it may have been the heater core at first too, but no no leaking that i can see. Ill try this weekend and see if maybe its leaking from the engine compartment side

Now i do have a slight sqeaking from the engine compartment from i suppose one of the drive belts but it only starts sqeaking after warming up and its a very slight, but constant squeaking noise. I've taken the belts off and checked the them though and they look alright. Do you think a tension problem with a belt could cause any problems? Also is it safe to remove the drive belts and run the vehicle cause i may also try that at least to pinpoint which belt is causing the squeaking

cman1

iTrader: (1)

i think what your hearing may be air in your system from when you flushed the radiator,leave the radiator cap off and rev the engine SLIGHTLY to try and push the air out of the heater core.might be a little messy...but...cheap fix.

mynameistommy510

The constant squeaking noise could be from the idler pulley (Bottom passenger side pulley). It wouldn't hurt to remove the idler pulley, then either replace the bearing or spray some lubricant on it. Just a thought. I also get that hissing sound every now and then but just ignore it.

Hme057

Actually i just drove around and let it heat up and decided to check the ac low pressure line. I plugged in a guage and watched as the pressure kept building up untill it hit around 45 PSI or so and then it clicked and made the hissing noise and the PSI dropped down to 23 or so but repeated itself as the pressure built back up to 45 again in a matter of maybe 10 seconds, this with the ac on cold at full blast so im assuming that my compressor is kicking off when the low pressure end hits 45 because its too high? also the belt begins to squeak when it kicks off and settles down when it hits 23 and begins to climb again, so my question is what could be causing the pressure to build up like that and cause the compressor to cycle? is my compressor about to die or maybe the belt is on too tight or too loose or a clog in the system? im not sure what to think

Hme057

thats funny i was writing as two new posts came in

i can try to rev the engine and get air out, you may be right that air could be in there. Right after i flushed the system there for a week i would get a little air bubble in the upper radiator hose ill go try that now

Now the idler pulley, is that the little pulley thats at the very bottom of the vehicle, with the nut on it and another faster nut holding its place?

I also forgot to mention that when i was flushing the radiator there was a little accident where the funnel i was using to dump distilled water in to flush out the old coolant got sucked into the radiator fan and somehow got pinned under the ac compressor. The funnel didn't break and from what i could see there were no problems but after that is when all this business of the noise and vibration began as far as i can remember, but ill go and try those suggestions today and see if it helps

dhracer3

Id be very interested in finding an answer to this problem.
I have what sounds to be the exact problem to. When I bought my 2000 4runner it had that same swishing noise. It sounds like its from behind the firewall on the passenger side.
To me its sounds somewhat of a Swishing of fluids. like an air bubble.
Mine on the other hand wasn't as bad as your it sounds but seems like mine is gone for now.? I really didnt do anything to make it go away just kind of gone now.

The other noise I have is when decelerating I have a funny chirping noise coming from the engine it seems or underneath the truck?
Only when decelerating. I relubed all the U joints but didn't help.
I have a full Timing belt kit coming in soon so hopefully next week I can get around to replacing everything there including the idler rollers. I'm thinking the chirping could be from the water bump or the Idler pulley? Maybe just a dry bearing.