Overheating

Tiny
SAAM
  • MEMBER
  • 2007 CHEVROLET TRAILBLAZER
  • 4.2L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 10,000 MILES
Hi, I am experiencing an over heating issue with my vehicle. I have changed the water pump, thermostat, cleaned radiator, and the head gasket was replaced.
Now the car is getting overheat when air conditioner is on.
My mechanic is now telling to replace fan clutch as the rpm is around 700.

Please guide me in this issue. How much is the normal rpm of radiator fan?
Hope reply asap.
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Thursday, June 30th, 2016 AT 3:13 AM

8 Replies

Tiny
HMAC300
  • EXPERT
When air conditioner is on the fan should lock and might not be, scan for codes as yours is a semi electric hookup and may not be doing that. If only overheating with air conditioner on he may be right and it is not working. It may not be increasing speed when you rev the engine. Also make sure you do not have things like bug screens in front of radiator/condenser as they cut 15% of air flow.
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Thursday, June 30th, 2016 AT 6:19 AM
Tiny
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  • MEMBER
Thanks for the reply
So now as you told I need scan for error codes. If there is error I need to replace fan clutch?
There is no debris in front of condenser.
If fan clutch is bad it will it show in computer scan?
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Thursday, June 30th, 2016 AT 9:32 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
If the fan clutch is weak or bad, it will not increase the fan speed as under hood temperatures increase. Thus, it will overheat. Since everything else has been replaced, that would be what I suspect is bad. I have, however, seen situations where the lower radiator would collapse under certain conditions. Therefore, when the engine begins to get hot, check both the lower and upper hoses.
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Thursday, June 30th, 2016 AT 7:53 PM
Tiny
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  • MEMBER
Is that 700 rpm's for radiator fan not enough after engine warm up to keep it cool with air conditioner on?
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Thursday, June 30th, 2016 AT 7:58 PM
Tiny
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  • MEMBER
Thanks a lot for the response. I will give an update once it is done.
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Thursday, June 30th, 2016 AT 7:59 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
That actually sounds slow.
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Thursday, June 30th, 2016 AT 8:42 PM
Tiny
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  • MEMBER
Hi I want to give an update.I checked my fan clutch it was not engaging

I kept a 10 amp fuse in pin 2 and 4 of relay no 45 in fuse box. The thing I noticed is the fan clutch is engaging when I am running like this and the temperature stayed in normal limits. No more over heating

But once I remove the 10 amp fuse and connct back the relay no 45 . The fan clutch is not enganging and again the problem of over heating
I swap the working fuse 45 and 46. The fuse is working
What may be the other possible cause for that
1. Relay is working
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Thursday, July 7th, 2016 AT 9:50 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Check all connections to the relay to make sure there isn't a corrosion issue or a pin that has been pushed in and not making contact.
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Thursday, July 14th, 2016 AT 6:39 PM

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