04 Chevy big block weird running problem

poacher240

2003 1500 siverado engine cooling fan

Unread post by poacher240 » Mon Apr 26, 2010 4:51 pm

The engine cooling fan does not seem to kick out, making accelerating and driving at crusing speed loud. I think I can hear the belt slipping too but not all the time, just when ecelerating. Any sugestions?
thankyou for your time
V8 5.3

Bob

Re: 2003 1500 siverado engine cooling fan

Unread post by Bob » Tue Apr 27, 2010 7:27 pm

If the fan is extemely loud, then the fan clutch has failed and needs to tbe replaced.

poacher240

Re: 2003 1500 siverado engine cooling fan

Unread post by poacher240 » Wed Apr 28, 2010 7:59 pm

Fan clutch replaced and working great. I like a easy fix

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butchkaz
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Posts: 173
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Re: 2003 1500 siverado engine cooling fan

Unread post by butchkaz » Wed Apr 28, 2010 9:34 pm

poacher240 wrote:Fan clutch replaced and working great. I like a easy fix
Good job Bob, thanks for your expertise !
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alewicki37
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Joined: Thu Jan 31, 2013 8:12 am

04 Chevy big block weird running problem

Unread post by alewicki37 » Thu Jan 31, 2013 8:26 am

I got a 04 2500hd with the 8.1l motor. I had to replace the motor because the old motor was ran with no oil. I had it running great and put about 500 miles on the new motor. It was running great and I got up to go to school the next morning and went out to start it. it started fine and I went back inside for ten minutes and when I came back out it was idling rough, the check engine light started flashing so I didn't drive it that day. I ended up reading the codes from the computer and it was saying that cylinder 7 and 8 were miss firing at the same exact time I tested pressure and everything like that. then while trying to rev it a big clunking noise started like the timing was off. it also wouldn't rev above 3000rpm. it would just totally max out at that. what I don't understand is that I had it running great for about 500 miles before all this happened...I am extremely stumped and would like some advice. thanks

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ProTech
Posts: 651
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Re: 04 big block weird problem

Unread post by ProTech » Thu Jan 31, 2013 8:42 pm

If you have a misfire still on cylinders 7 and 8, you really need to look in that area. It doesn't matter how fine it was running before, as anything can go wrong at any time. Did you purchase a new GM engine? Or did you get a remanufactured unit or junkyard engine? If was either of the latter, you could have gotten a bad piece. Maybe it's a valvetrain problem, like lifters or rockers, if it's noisy. Possibly its just an ignition issue, like a normal misfire. You might want to try a compression check, and then check for spark, etc....all the basics first.

If you can't find anything, try removing a valve cover and looking for issues like a broken valve spring, broken rocker arm, or lifter that has failed. Worst case scenario, something broke inside in the engine and it will need to be replaced again or taken apart and repaired. Hopefully it's just something simple.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

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