Question about 1990 GMC Sierra

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1990 GMC sierra.. check gauges light/temp rising

So lately I've been having a good deal of trouble with my truck.. started off with the check gauges light appearing ended up breaking down and putting in a new battery, alternator, and fan belt. The new belt kept slipping off the pulley and I was told i needed a new tensioner. After replacing that and the idler the belt still slides off. Every few days the belt seems to come off causing me to lose power steering. All of a sudden the check gauges light is popping up again, seems to be that the temp gauge slowly rises causing the check gauges light to pop up, then the temp drops and the light goes off. The only thing that consistently makes the temp gauge rise is turning up the heat.. other than that I can't figure out what's going on. Any ideas or suggestions would be awesome.. Thanks!

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The belt should not come off. If it didn't come off before the new alternator was fitted it should not came off now and the fact it does should not be your worry but the worry of the person who specified the repair, supplied the parts and carried out the repair. You presumably paid somebody to cure a problem and not to provide you with a whole new problem.

Clearly the new tensioer has not cured the problem...

If the pulleys are undamaged, perfectly round and the alignment is correct and the belt is tight enough, it should not come off.
If the pulleys are ok and the belt is coming off then the belt isn't tight enough. I assume the tensioner is a spring loaded automatic type?

If it is a spring loaded type, it indicates something sometimes is needing so much power to keep it turning it is overcoming the tensioner spring pressure and creating a slack belt.

Sorry but other than that mad idea I have nothing to offer...

Posted on Mar 19, 2017


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SOURCE: Rattling & Squeaking coming from front of motor...

there is a vacuum line PCV that goes to the drivers valve cover the hose could be broken down and causing the noise could be other things but that is the first thing that comes to mind

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SOURCE: Rattling & squeaking coming from front end of motor..

I'm takin a stabe at this one, I think it may be coming from your waterpump. Use a long piece of metal or a pry bar and place it on any part of the pump that you can safely put it while the truck is running. Put your ear to the bar and you should be able to tell if it's coming from there. Good luck!

Posted on Dec 30, 2008

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SOURCE: 2002 gmc van overheatig

It has a leak. Fill up the radiator and the coolant tank. Then restart it and check for leaks.

Posted on Mar 13, 2009

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SOURCE: I need to replace a serpentine belt on a 2001 GMC

it is decieving. if the tensioner has an extension of about two inches from the base, it takes a 15 mm to lift it, be easy, make sure the wrench is not going to touch anything as you release it after taking the belt off

Posted on Sep 18, 2009

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SOURCE: 2004 Yukon XL Denali fuel gauge fluctuations

You can get the codes checked and see if you have a level sensor code.The level sensors are known to go bad on these vehicles.Sometimes when you rock the vehicle it will start to work properly.What happens is the fingers on the level sensor wear out and it works erratically.You can get the level sensor separately from the fuel sending unit.Hope this helps.Good luck.

Posted on Dec 18, 2009

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