Chasing a squeal - 1400-1600rpm

[Rooboy84 Lurker Find all posts View Profile Close Rooboy84]

Hi crew,

I have just recently purchased a 2001 TX 3.0TD with a paltry 148k on the odo.

So far so good, beautiful car to drive and well built, I've owned Toyotas in the past and very happy with the Prado thus far.

Just recently the vehicle has developed a noticeable 'squeal' which is both audible inside the vehicle and outside. Sound is only frequent and/or constant between 1400 and 1600 rpm. The fan belts were pretty cooked when I purchased the car so I initially thought that replacing these would rectify the issue, not to be.

I hunted the forum and found the 'return spring stretch' on the diesel pump and this sounded like my exact symptoms. Spring was removed, stretched, and reinstalled. Again, no help.

Today I loaded up all the universal joints, I have a mini grease gun so getting to the nipples inside the joints on the front prop shaft was no issue, again, sound remains. There was a noticeable amount of grease splatter on trans tunnel, unsure whether this indicates a dud joint?

The only clue I can provide anyone at the minute is that the fuel consumption has shot up to around 18L/100km and this has obviously not always been the case. Last fill of main tank returned 12L/100km. I will also say that the sound does not exist when vehicle is stationery, even when the rpm is increased.

Brake pads have all recently been replaced also.

Apologies for the long-winded post, just struggling to find an answer at the moment.

Thanks in advance for any advice.

[Guest Close Guest]

Sounds like something dragging when it's rolling. Diff bearing?
Sticking brake caliper?
Dodgy wheel bearing ?
Handbrake dragging?

Have you had it on a hoist and run it up? Should make it easier to find.

[carco Advanced Member Find all posts View Profile Close carco]

Before you go anywhere pop the timing belt cover and check condition of the tensioner bearings.
The fact it's RPM related is concerning, if the belt snaps or the bearings collapse it gets expensive really quickly.

[Guest Close Guest]

Before you go anywhere pop the timing belt cover and check condition of the tensioner bearings.
The fact it's RPM related is concerning, if the belt snaps or the bearings collapse it gets expensive really quickly.

The OP said the issue does not exist when vehicle isn't moving, suggests it's not motor related.

To the OP when your driving and pop it into neutral. And just roll. Does it seem to roll to a stop quicker than you would expect without brake input?

[carco Advanced Member Find all posts View Profile Close carco]

Ah, I misread that bit.
Since it's so specific in the rpm range I'd be looking for a boost leak.
Those clamps at the throttle body are notorious for leaking, usually evidenced by oily residue around the whole area.
Also check the clamps on the turbo to intercooler hose.
Any leak will usually have oily stains so a thorough clean, then inspection after a drive.
Have seen some intercoolers falling to bits lately which results in boost leaks.
Boost leaks can sound like the reed from a musical instrument and are linked to load/boost/rpm.
Hanging brakes for sure, they'll eat your fuel but the heat generated is a dead giveaway so feel your hubs…...carefully.
I had a front wheel bearing problem that also ate fuel and about 50hp. Man it got hot.

[Rooboy84 Lurker Find all posts View Profile Close Rooboy84]

Thanks for the prompt replies. Appreciate it.

I will prob get under the truck and see if there is any significant play in the front uni, this one looked the worse for wear.

Didn't notice anything significant with braking/neutral, the brakes were almost metal on metal prior to replacement so maybe something in that? (rotors were replaced)

I will hunt for a vac leak also and keep you posted on the outcome.

[RobboMC Junior Member Find all posts View Profile Close RobboMC]

One easy way to check for a binding brake - give it a push!! But make sure someone is in the drivers seat first.

But being rpm related it's surely in the boost system somewhere.