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Dom · 07-07-2020, 08:52 PM

I've seen several threads on this issue but no real solution . High pitch squeal going up a hill, constant until the top then when let off of accelerator is fine. It is NOT a belt, not an air cleaner issue. If anyone has had this and had a solution please post
Sorry 2014 F53 chassis

TeJay · 07-08-2020, 06:20 AM

I don't have an answer for you as such. This is how I'd start looking. Based on past experiences what items, circumstances etc can cause a high pitched squeak?

How or why did you decide it's not a belt or involved with the air cleaner?? I'm not doubting you just wondering how you reached those conclusions?

Bearings is one answer. Where and why? Going up a hill the engine is under a load placing more stress on everything. The load on all spinning items is greater and for sure a place to start looking. Which bearings? There's a bearing involved with the belt tensioner. Also the alternator is under more load and it has two bearings.

You said the noise stopped when you took your foot off the gas pedal. Did you try that half way up the hill or just after you reached the top?

Another area would be air flow through the air cleaner. It's possible air flowing through the exhaust or intake can set up vibrations.

Was the AC working while it's making the noise? Our Honda CRV makes different noises when the compressor kicks on. It's not a squeaking noise but that just illustrates how different noises can happen under different circumstances.

How to locate the noise? If you brought me your RV and this noise could be repeated by placing it under load while climbing a hill I'd take the dog house off and with an assistant using a stethoscope we'd climb a hill and try to locate & isolate the noise.

This is a trick I've used many times to isolate a belt. When it's making the noise I'd squirt belt lube directly on the belt. If the noise stops or changes it's a belt. Maybe that's how you determined it wasn't a belt?

Dom · 07-08-2020, 07:42 AM

Thanks TeJay, I have narrowed it down to air flow but don't know where/what. I've had lots of belts and bearings squeal and they have a certain sound, especially belts. Someone had a similar complaint and it turned out to be head gasket. God i hope not!.. At first it only did it intermittant, but got worse lately. I like your ideal of the dog house say may do that. I would take it to a shop, but don't want to pay for their guessing.

sbleiweiss · 07-08-2020, 08:17 AM

I have had that on both F-53 chassis MHs I have had from day 1. I have been told two things, the second of which I think I believe. First I was told that it was a function of the air over the front grill. Second, I was told that it is the clutch fan (or is it transmission fan?) kicking in. Normal and not a problem. I want to believe that one. BTW, I can make the noise stop anywhere up the grade by letting slightly off the gas pedal.

TeJay · 07-08-2020, 09:15 AM

Dom,

I forgot this trick. If you use some carburetor cleaner and when it's making the noise spray it around the intake manifold. If there's a leak it will suck the cleaner in and change or stop the noise.

I don't blame you for not wanting to take it to a shop. For some reason the techs these days are reverting back to what was done before the computers came on board. The mechanics just changed parts until the issue was fixed.

After 1980 the manufacturers concentrated on diagnosis, diagnosis, diagnosis. They didn't want to waste $$$$ on just guessing. Now their back to guessing and forgot diagnosis.

Here's a little know statistic. Starting in 1980 and going until about the mid 80's when a mechanic couldn't figure out an issue they just changed the "BRAIN" or the PC. Those units had to be sent back to the factory to determine what went wrong. Funny thing is better than 90% of those "BRAINS" were just fine. The defective brain was with the mechanic. Everybody blamed the computer because they couldn't diagnose.

We have a 2013 chassis and in 43,000 miles I've heard the clutch fan kick on one time while going through some mountains in NH or VT. Doubt very much it's the CF.

Wind whistling through the grill I doubt as well. If you're going up hill the wind is slowing. While going down the other side the wind is really going strong. Varying winds but slow going up and fast going down making noise very questionable. But many things can cause it. Easily checked by just sliding a piece of cardboard in front of the radiator. That will disrupt the wind flow. If it's grill noise it will change or go away.

Dom · 07-08-2020, 07:08 PM

TeJay great tip I'll try that

sbleiweiss · 07-09-2020, 08:25 AM

[QUOTE=TeJay;
We have a 2013 chassis and in 43,000 miles I've heard the clutch fan kick on one time while going through some mountains in NH or VT. Doubt very much it's the CF.

Wind whistling through the grill I doubt as well. If you're going up hill the wind is slowing. While going down the other side the wind is really going strong. Varying winds but slow going up and fast going down making noise very questionable. But many things can cause it. Easily checked by just sliding a piece of cardboard in front of the radiator. That will disrupt the wind flow. If it's grill noise it will change or go away.[/QUOTE]

Thanks TJ, although worrisome.

Waiter21 · 07-09-2020, 10:50 AM

You'll notice when the CF engages, it sounds like your standing behind a 747 at takeoff thrust.

the V10 sucks in a lot of air at full throttle. I'd inspect all the ducting and connections for loose or bad connections. Look at the hoses for cracks. Take a peek inside the air filter box and plenum for an air filter that's falling apart. I replace mine every year, usually with less than 10k miles on it.

While you have stuff torn apart, get a can of MAF sensor cleaner and squirt the sensor down real good.

Dom · 07-09-2020, 07:45 PM

Quote:

Originally Posted by Waiter21

You'll notice when the CF engages, it sounds like your standing behind a 747 at takeoff thrust.

the V10 sucks in a lot of air at full throttle. I'd inspect all the ducting and connections for loose or bad connections. Look at the hoses for cracks. Take a peek inside the air filter box and plenum for an air filter that's falling apart. I replace mine every year, usually with less than 10k miles on it.

While you have stuff torn apart, get a can of MAF sensor cleaner and squirt the sensor down real good.

I did air cleaner but will try MAF sensor cleaning Thanks Almost sounds like some valve is weak and letting go under load. Don't even know if there are any valves attached to vacuum system, but thats what it sounds like