Topic: That squealing sound...
in Forum: C3 Engines
it's coming--unfortunately--from the front of our L48. And I could sure
use some advice on how to figure out just what's causing it.
No obnoxious noises from this powerplant until I changed both radiator
hoses yesterday (BTW, that lower one was a bear to do!). Now, I'm getting
a continuous squeal from the fan/pulleys/pumps area. The A/C and A.I.R.
belts are off, and the water pump/alternator/power steering belts that are
still on seem to be in OK condition; not new, but not worn out yet either.
A PO obviously had a problem with the fan hitting the shroud, because
he/she cut away a portion of the upper shroud for clearance. But Bubba/
Bubbette didn't bother to attach the shroud very firmly; it was loose
enough to move around some. So I fixed that problem yesterday with new
bolts on both sides. The fan turns by hand without rubbing, although I
wonder now if, with the engine running, maybe it's flexing and hitting
somewhere new? Potential other causes: maybe the water pump and/or
the power steering pump are going bad? I can't isolate exactly where the
squeal is coming from, although I'm certain it's not the alternator itself.
There was some rust in the old coolant; I found flecks of it inside the
thermostat housing. (Unfortunately I couldn't drain the radiator entirely,
because I can't remove the drain plug. It's jammed up against a flange on
the radiator support, and right now I can't risk damaging the radiator
trying to remove it, because a replacement's not in the budget.)
Would the changeover of the hoses have loaded up rust in the water
pump, causing it to go bad? Should I get some belt dressing, to try to
eliminate the question of bearings gone bad? if it is a bad water/PS pump,
is there a way to diagnose which may be the faulty one?
Ideas from anyone on solving this problem will be much appreciated...

remove the other belts one at a time...
as long as you dont run it very long its okay that the water pump doesnt spin..
OK...bad Deliverance joke. If the noise started after the work was done it must be related (though Murphy does work overtime when it comes to coincidences).
It could be as simple as the hoses that are on are glazed and slipping...they may not be able to take the load without the other belts present. When changing the hoses some coolant may have spilt on the belts and soaked into the belt material. That will make them slip... anti-freeze/coolant is very slick and will cause belts to slip.
If the fan was flexing forward and striking the shroud, I think you'd hear more than a squeal! You'd also see parts of the shroud and maybe even damage to the fan blades.
Of course Murphy could be at work here and the water pump bearing could be bad. You should be able to isolate that noise by listening to it while the engine is running. An automotive stethoscope would be a help here...a screwdriver with a very long blade can substitute in a pinch for that.
I'd start by buying all new belts and install them and see if the noise goes away. If it's still there, then start looking deeper, but it sounds like a belt problem from your description.
I would also suggest you buy oine of those flush kits & do a reverse flush. It's the kit they sell in most auto retail stores. You attach a fitting in one of your heater hoses, by cutting it and attach a garden hose to the fitting. Slide your heater control to max heat ( this allows the heater to be flushed)Then attach the angled plastic fitting to your radiator ..turn on the hose & let it go. If you removed your bottom hose you already drained your radiator. This flush does a pretty good job of flushing everything. After it flushed remove your lower hose or at least let the water drain. Then deattach the hose & leave the plug attached to the heater hose open. Pore in the antifreeze ( in the radiator)until you see green antifreeve coming out of the plug then seal it & you'll be pretty close to a 50% solution.
Alan

C3VR Lifetime Member #93
It sounds like a belt to me.
I have a spray bottle with water in it, when the engine is running, spray some on one belt, then another, till you hear a change in sound ( sometimes the noise will go away), that will be the one to change.
The noise will come back as soon as the belt dries.
I have used a cup of water, but, you may get wet!
Hope that helps,
Denny

Moderator
If the water tourture doesn't give up a clue, then it's possible the water pump bearing(s) may have taken a dump after draining/changing the water out of the system. Take one belt at a time off,(or, you can sometimes get by with just loosening them up) and see if the noise is associated with one component.

Now....let's invite Mr. Murphy in on this...

There could be a similar noise coming from the harmonic balancer. If the outer ring of the balancer has slipped on the rubber, it can move rearwards, toward the timing chain cover. Depending on how hard it is actually rubbing on the cover, it could make a skweek/skweel, rattle, or grinding noise.

A fan hitting on the shroud makes more of a banging noise.

Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Had a similar problem when I changed out the lower rad hose on my Jeep just last month. Rad fluid got all over everything (no laughing, it wasn't pretty!) and a squeal developed after I was done. A little WD40 on the bearings of the water pump made the squeal go away until the WD was worn out or flung off. Either way, turned out my water pump had a crack in it anyway.
I suggest starting at the water pump. Check the belt first, then inspect for cracks and/or leaks above and below.
Also, there is no mention whether you have AC on the vehicle. The bearings on the compressor clutch may be going bad, or the clutch could need adjusting. These are the only two areas I have had experience with on the squealing topic.
Hope we've helped!
Went out to resume work on the car yesterday, armed with all the wise
advice from the above first responders--and upon firing her up, got no
noise! (Well, none except for the happy revs of a freshly oiled, filtered,
hosed and watered L48, that is...)
Happy and relieved were the words of the day. Don't know why the
situation cured up all by itself, but my best guess is that it was wet belts
from some splashed antifreeze. All I do know is that the wallet was
spared--probably temporarily, but I'll take it--from a new water/PS
pump, or other significant expense.
So a big thank you to cthulho, gunslinger, knotacare, ron78, xfire, Joel,
and vettedreams79 for the fast help and excellent advice--which I know
will come in handy someplace down the line.
This forum is the best...because of members like you.