Squeak changes with RPM after Thermostat replacement

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bk10s

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Recently replaced belt, water pump, thermostat, and purge sensor. Have a persistent squeak that changes with RPM. At first I thought it was possible from spilled coolant, but it has been over a week. Any idea what that could be?
 

blert

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Did you also change the belt tensioner? They wear out too and should probably be replaced with the belt. Is cheap and easy.

The idler pulley wears out also. Another item to inspect and replace with the belt. Is cheap and easy.

Some spray lube can help to find if the bearings in one of the pulleys is squeaking. Hit one at a time until you find it. Careful not to spray the belt.
 

swshawaii

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blert, good call on the belt tensioner and likely the source of the squeak if it wasn't replaced. Learned years ago from Todd Z the first thing to isolate squeaks and chirps is remove the belt and spin ALL the pulleys by hand and check for binding. If OK, start the cold engine for less than one minute to rule out internal engine noise. If the squeaking stops, clean ALL the pulleys and belt with a stiff nylon brush and dish soap. Amazing the amount of crud that comes off. Worst case may be a faulty harmonic balancer aka crankshaft pulley. I'm a fan of the possibly discontinued Goodyear Gatorback (Contintenal Elite) belts. Chased a start up squeak for years using a Gates six rib belt until I replaced it with the Gatorback. Quiet now.
Gbvgjki.jpg
Nzj9CBN.jpg
 
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blert

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Be careful with soap and water around the pulley bearings. They are sealed bearings but the seal is not water tight and if soap gets in the bearing will die shortly after. They can be re-lubed but replacing them is fairly inexpensive and beats pulling them out, carefully removing the seal, clean and re-lube, and reassembling.
 
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swshawaii

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Thanks blert.

"Sealed" bearings has a new meaning to me. I suppose brake cleaner would be worse?
 

blert

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Yeah, probably not good. Same reason why you should never hose down your bike or skateboard. Water, rag, and wipe down. I have some expensive BMX bikes with sealed bearings all around and some RC cars which have more sealed bearings in a small space than just about anything. The plastic shields can be removed and then you can clean them out and re-lube. Works well on the RC cars as the bearings are quite expensive but the bikes just get new bearings if needed.
 

swshawaii

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Before removing the belt start the engine and look at the tensioner pulley for movement. Broken or weak spring in the tensioner usually results in wobble.

Also check if the tensioner mark is close to center of the outer marks with the engine off.
lcA1ylg.jpg


This is a Gates tensioner and identical to OEM.
nZ30Sja.jpg
 

Max8

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I had a similar problem with my 2005 Lt v6 sport trac. After change thermostat housing and water pump I had a squeak that would start at start up increase with rpm then after a bit stop. I went back and changed idler pulley with no help. It continued for awhile then truck would shut down randomly when squeak started . Finally found harmonic balancer rubber was torn @ 75% around allowing balancer to contact the crank position sensor causing the squeak. Squeak would stop once balancer trued up. When I finally found it it had ground about half way thru the sensor exposing the interior and grounding out on harmonic balancer causing the shutdown
 
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