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Loud Screeching Noise on a Chevy Blazer

16 messages,  Last post on Jul 20, 2009 at 7:40 PM

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What is this discussion about? Chevrolet Blazer, SUV

Messages Page 2 of 2

#7 of 16 Re: Loud Screeching Noise [wesx] by wesx

Jul 03, 2009 (2:17 pm)

Replying to: wesx (Jun 26, 2009 2:41 pm)
No ideas?

#8 of 16 Re: Loud Screeching Noise [wesx] by tidester

Jul 03, 2009 (3:01 pm)

Replying to: wesx (Jul 03, 2009 2:17 pm)
Have you followed through on jflemmons' suggestions?
 
The leaking fluids would have me concerned. Can you describe the fluid? Odor, viscosity, color? That might help someone diagnose your problem.
 
tidester, host
SUVs and Smart Shopper

#9 of 16 Re: Loud Screeching Noise [tidester] by wesx

Jul 11, 2009 (4:03 pm)

Replying to: tidester (Jul 03, 2009 3:01 pm)
Yep I have tried what jflemmons' suggested. When it's sitting in park you can turn on the AC and everything else and it's fine. It doesn't do anything until it's pulled out of park.
 
The fluids are a darker color. Like a dark brown. I checked both fluids that are leaking and they smell like the same fluid. Maybe these pictures could be of some assistance:



#10 of 16 Re: Loud Screeching Noise [wesx] by tidester

Jul 11, 2009 (10:58 pm)

Replying to: wesx (Jul 11, 2009 4:03 pm)
I wonder whether that could be differential/transmission oil or something from your power steering. Anyone with hands on experience - please jump in!
 
tidester, host
SUVs and Smart Shopper

#11 of 16 Re: Loud Screeching Noise [tidester] by jlflemmons

Jul 12, 2009 (3:54 pm)

Replying to: tidester (Jul 11, 2009 10:58 pm)
Okay, for the oil pan, check to see that all the oil pan bolts are tight. I have seen these back out and allow the oil pan gasket to leak. The good news is that the worst one I have seen did not leak once it was tightened back up. Surprised me, that usually doesn't work that way.
 
The differential is interesting. That is not the typical leak pattern for a bad gasket. I see a lot of rust on the cover, check carefully that there isn't a hole.
 
Re the squeal when put in gear; has this been in water? You might need to drop the tranny pan and check for water, dirty filter, etc.

#12 of 16 Oil pan drain plug by duntov

Jul 13, 2009 (6:23 am)

Many times the oil pan drain plug treads will be stripped by a over zealous jiffy lube technician in an attempt to cover himself in case of a oil leak followed by an engine failure. The oil pan drain plug should not be torqued more than 18 lb, or you will risk stripping the threads in the caged nut in the oil pan. The drain plug should always be equipped with a fiber gasket which does most of the sealing. Often a technician or car owner will replace a pefectly good 1/2"-20 drain plug in an attempt to prevent a leak. Usually that will not seal the leak because the treads are stripped in the caged nut in the oil pan and not the threads in the drain plug. . If the caged nut in the oil pan is stripped, the drain plug must be carefully replaced with a 1/2'-20 OS (over size) drain plug and new fiber gasket. The OS plug will not cut new threads in the caged nut but will chase (recondition) the present stripped threads in the nut. Always replace the fiber drain plug gasket after two or three oil changes. There are also double-oversize oil pan drain plugs, but do not use one of those until a single oversize drain plug does not seal. Some drain plug gaskets gaskets are nylon and may last longer. I have a 1988 Ford, 1999 Ford, and a 1991 S10 Blazer and every one has a stripped oil pan caged nut. That is because out of haste, I had the oil changed several times at the drive through quick lube "strip joints". ........Never again.

#13 of 16 Re: Oil pan drain plug [duntov] by jlflemmons

Jul 14, 2009 (8:23 pm)

Replying to: duntov (Jul 13, 2009 6:23 am)
Is the oil pan steel or cast aluminum? It appears to be the aluminum from the pictures, but hard to tell. The aluminum oil pan doesn't use a cage nut, it has threads in the casting, and uses a drain plug with a fitted neoprene gasket that is not replaced unless it leaks from a tear or such. Real pain in the butt to find the right one, too. Dealers have them, and a friendly mechanic might give you one. GM went to this design when they started using cast aluminum oil pans. I have seen them on V6 and V8 engines both.

#14 of 16 Cast aluminum by duntov

Jul 15, 2009 (7:59 am)

I forgot about it being a cast aluminum oil pan. GM started installing cast aluinum oil pans on 1995 and newer S10 Blazers. My 1991 S10 Blazer 4WD has the deep steel pan with a caged nut. I had to install a 1/2"-20 OS drain plug in the pan thanks to a technician at a oil change strip joint.
 
The 1995-up S10 Blazer aluminum pan requires a M12 x 1.75 drain plug and that plug with an oversize thread can be purchased on-line at CG Enterprizes ( www.cgenterprises.com ) which is their #1027 drain plug and #2201 gasket. A better option would be to install CG Enterprises #1048 M12 x 1.75 OS double (piggy-back) drain plug and a #2201 gasket. You can install the OS double drain plug with Loctite #262 permanent thread locker and never have to remove the M12 x 1.75 drain plug again. In order to drain the oil, you remove the smaller "piggy-back" drain plug that is threaded into the main M12 x 1.75 drain plug that you have permanently locked in the pan with the Loctite thread locker.
 
The very last option would be to replace the oil pan with a new one. Unfortunately, you must remove the engine to do that. The high cost of replacing a oil pan is why the OS drain plugs and the piggy-back drain plugs were invented and introduced.
 
"When the price of eggs get high enough, roosters will start laying"

#15 of 16 Loud Screeching Noise by wesx

Jul 17, 2009 (3:33 pm)

Ok, today I went out and rechecked all the fluids. All of the fluids were full and looked clean. The radiator was a little low on fluid but thats it. The fluid leaking on the ground under the differential is a light gold color.
 
I also played around with the shifter some more and it only makes the loud noise when it's put in to or taken out of drive. It doesn't do it with park, reverse, neutral, 3, 2 or 1.
 
I also noticed that the check engine light was on. I ran the codes and it came back with a bad O2 sensor. I also think that the catalytic converter is bad.
 
Could the cat be the cause of the loud noise?
Also, is replacing the cover for the differential difficult or is it just taking the bolts off and replacing the cover?

#16 of 16 Re: Loud Screeching Noise [wesx] by jlflemmons

Jul 20, 2009 (7:40 pm)

Replying to: wesx (Jul 17, 2009 3:33 pm)
Differential cover is easy. Pull the old one, clean all the gasket material from the carrier. Apply Permatex Black per the instructions on the tube, and reassemble. Will take about 1 2/3 quarts of synthetic 80W90.
 
Regarding the noise, any chance a heat shield is coming in contact with the linkage when in the drive position? May need to put this one on a lift to isolate the location.
 
The typical noise from a bad cat is a marbles in coffee can sound, or a loud sucking/whooshing sound if plugged.
 
A vacuum leak can trigger a false O2 sensor code. Several mechie's have told me the O2 sensor is the most common mistakenly identified failure around.

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