Barely Audible, new sound after overheating

[Fried_Chicken]

So my accessory belt decided to eat my expansion tank a few months back, causing my car to briefly overheat (called AAA and had it towed home).

Now I may be imagining things, but it sounds like the engine makes this really high pitch hissing noise at idle. It kind of sounds like an old school fuel pump, but it's coming from the front of the engine. It appears regardless of engine temperature, or A/C on or off.

It's persisted after an oil change, so I don't think it's coolant in the oil. It could be a normal sound, but I swear it wasn't there prior to overheating.

[san]

How did the oil look when u drained it?? I think it should look light brownish if it got mixed with coolant... And by briefly how long do you mean?? Others can correct me but I think if it's over 30sec then it's not good


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[Karl Lazlo]

Others can correct me but I think if it's over 30sec then it's not good


When my idler pulley grenaded itself, launching frags into my expansion tank and the resultant rapid coolant loss caused my 03 to overheat, it was well over 30 seconds. I would rather risk a warped head by parking well off the highway than being waffled waiting for a tow on the side of an interstate, at night.

New bits installed and no permanent damage to the motor.

[Fried_Chicken]

How did the oil look when u drained it?? I think it should look light brownish if it got mixed with coolant... And by briefly how long do you mean?? Others can correct me but I think if it's over 30sec then it's not good


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Less than 30 seconds. The oil looked fine. I might make a video of the engine running. Like I sad I'm being really nitpicky.

[BCS_ZHP]

So you threw a belt, did you ever determine the root cause? If you have a bad tensioner, idler, or pulley, it's now eating up your new belt and likely the source of your noise.

Start the engine, take a long screw driver, and be careful to not touch any moving parts. Set the far end of the screwdriver near the rotating pulley or idler, touch it against some metal, set your ear on the handle end of the screwdriver. You'll hear the one that is roaring too much, that's your bad part and the pulley/idler you need to replace. Be very careful with this test, if you touch something that's moving with this screwdriver, it will rip it out of your hands and throw or break the belt.

[Fried_Chicken]

So you threw a belt, did you ever determine the root cause? If you have a bad tensioner, idler, or pulley, it's now eating up your new belt and likely the source of your noise.

Start the engine, take a long screw driver, and be careful to not touch any moving parts. Set the far end of the screwdriver near the rotating pulley or idler, touch it against some metal, set your ear on the handle end of the screwdriver. You'll hear the one that is roaring too much, that's your bad part and the pulley/idler you need to replace. Be very careful with this test, if you touch something that's moving with this screwdriver, it will rip it out of your hands and throw or break the belt.


No. The expansion tank/radiator wasn't sitting properly on its mounts which caused the whole thing to move back towards the engine which resulted in the belt eating a hole into the expansion tank.

[Fried_Chicken]

I believe I’ve figured out the source of the noise. There was air in the cooling system which must have caused some sort of cavitation or something resulting in a high-pitched sound. I believe this was the noise I’m hearing, flushing the cooling system properly (using the bleed screw) alleviated this noise.