mine whistles at idle, it cant be the IAC because it idles fine and its coming from the drivers side of the truck.

 

i'm going to look over the evap canister lines again. i replaced one but not the 2nd one... it's puzzling because it only happens at certain rpm's mostly on the highway in 5th...

 

i looked at the evap canister lines again and they all look good .. whistling is still there but intermittant... grrr...

 

Darn, I was hoping that was the fix. I ordered my new fan clutch for $50.00 and am waiting for it to arrive. I may try running around the block without the fan blades attached just to see if that isolates it. I'll keep you posted.

 

ive got the same thing going on. i just noticed it after i replaced my exhaust. i think the noise from the old one was covering it up...i cant find a vacuum leak anywhere but it seems to be coming from right around my throttle body.

 

mine hasn't done it for the past couple of days.. but it's been a bit warmer out here..

 

mine seems to run a little rough and has a little miss sometimes. maybe im just nuts, i always THINK i notice something. but i definitely DO hear the sound!

 

what were you using when you were trying to locate the vacuum leak? ive tried carb cleaner and propane on things before and have never had any results. ive even tried them on parts that i knew had a leak and it didnt do anything. maybe im using it wrong, but im curious as to how you were going about this. just with ears and eyes maybe?

 

hmmm. i wouldve thought it was your IAC...

 

try using brake clean. my guess is its the throttle body gasket hows the intake hoses

 

Thanks for the tip. I'll check my throttle body gasket and see if that's it. Maybe during my transmission removal it got bumped just right to produce a small leak.

 

The 94 I used to have had a penchant for cracking alternator housings.It would still charge until the bearings got chewed up. It squealed worse some days than others .Pull your alt and check the bottom/back side for cracks.

 

My intake hoses look really good. I will check the alternator for cracks but I'm starting to think it's vacuum dependent. 94RangerGuy2007 suggested using brake cleaner to check for the leak in the gasket. Do you squirt some near the gasket and listen for a change in idle?

Thanks,
Craig

 

Yes Spray It Where The Gasket Is All Over It. You Should Notice A Diffrince In The Idle If The Gasket Is Bad Hows The Houses Going To The Pcv ?

 

my noise was a belt. i swore up and down that it wasnt but it was. it didnt sound like it was coming from there when i was listening one day, but i sprayed some belt conditioner on there and it went away so double check just to make sure.

 

Problem solved! That's a big AMEN! No more whistle. After reading through the manual I finally located the PCV valve, which is an inline valve a little bigger than a thimble, located under the driver's side rear of the intake system between two hose connections (in a '94 2.3L 4 cyl). You can't really see the connection well but you can feel it if you reach from behind and under the intake plenum. I had not checked this fitting before and it had worked out entirely so the valve was hanging from the top hose in the air with the bottom side wide open. Now that's a vacuum leak if I ever saw one!

Now the story makes sense. . . . When I did my tranny work, I must have jarred the connection causing it to loosen while accessing the bell housing bolts. As I drove the truck over the past few weeks, the idle got rougher and the whistle got worse until it finally started pinging under acceleration today. It was probably working its way apart the rest of the way. The hoses are a little old and they don't have the stretch they had originally so they don't hold a tight connection even when pressed all the way together with the valve. It's possible that many people have a leak in the area due to old hoses. I'm going to intall a small hose clamp with light pressure on the connection (not too much or the valve might distort and fail to operate). I hope this helps someone else on the board who may have similar problems.

 

sure enough it's cold out now again and the whistle at about 2500rpms is back... grrr... it only happens when it's cold out ....it didn't do it all summer.
and ideas? the pcv is new and seems tight..

 

My guess is that a vacuum line somewhere is leaking only slightly. Maybe an old hose that is somewhat flexible in the warm weather could lose that flexibility in the cooler weather and cause a leak to open up? Maybe pull some of the connections and make sure they are tight. Also, I've read that many people report whistling near the cold air intake box so check for cracks along that line. Whistling tends to happen when air passes quickly through a small opening causing the edges to vibrate to it's probably going to be hard to see at first. I've also read some recommendations using starting fluid and mist it near connections to find vacuum leaks. If it is leaky the idle will respond because it will suck in the vapor. Let us know if you find it!

 

I forgot to ask if it seems to be in time with the engine (like some detectable pulse in the whistle) that could be belt or pully related? Many people have reported squeaky belts and pulleys following changes in weather, moisture etc. Sometimes it's hard to tell though. Mine sounded almost metallic like a pulley squealing but it was just air passing through the loose PCV connection. I wouldn't have thought it would sound like that. Does it tend to happen on acceleration up through 2500 rpm or any time going up or down through that speed? Squealing on acceleration only might suggest a vacuum leak too.

Good Luck!

 

it doesn't happen on acceleration , only when the rpms hit around 2500.. above or below that it goes away. the airbox connection and all up the intake into the throttle body are tight. also it doesn't depend on engine temperature only the outside temp. it's driving me nuts.. i'm going to check the bolts on the throttle body and see how they are...

 

Someone mentioned earlier in a thread that throttle body gaskets can be broken and cause whistling, probably like a saxaphone reed. Something to check if possible.

 

well checked the TB bolts and the intake tube etc and all is tight. i seem to have narrowed the noise to the front of the engine. i went ahead and changed out the serpentine belt but the tensioner was quite difficult to move. had to use a pipe slipped over an adjustable wrench to get it to move. the tensioner then moved back and stayed where i pulled it to. put on a new belt and then pushed the tensioner pully against it. sprayed some wd-40 into the tensioner pully as well . whistle sound is still there but not as bad...

what's next a new tensioner and pully assembly?

anyone have any pics/advice on how to get the tensioner off?

 

bah, it sort of self-healed. maybe spraying some wd-40 on the bearing of the tensioner and/or replacing the serpentine belt helped a bit. it still makes some noise .. but only when the outside temps are at, below, or near the freezing mark.

 

ahh it came back again... this whistle... changed the tensioner.. the old one was original and shot... didn't cure it.. but the part needed replacing anyway.
drenched the idler pully from the back in wd-40 seems to have quieted down - when i get the chance the idler pulley will be changed out for a new one. it's too dang cold to do anything out there now

 

swapping out the idler pulley should fix the problem, I had the same issue on my truck and after replacing the idler pulley I haven't heard anything

03XLT