Over heat at idle serpentine belt smoking

nbenjamin

Original poster
Member
Dec 7, 2011
76
Have not been aroumd for a while so a big hello to everyone
Don't drive the truck much. But a couple days ago I used to to go to a job
Sitting waiting I notices a burning rubber smell then it some squeaking sound. At first I thought it was my fan clutch
Then I notices the engine temp up so I shut it down right away
Smoke under the hood. Checked it was coming from the belt next to idler pulley
Let it cool took belt off next day checked water pump ( spins nicely ) checked AC bearing seems ok
Power steering ok. Belt tens pulley ok. Idler pulley bearing a little rough but spins freely
At 190 000 kilometers I have changed almost everything on this truck but the thermostat
But if it was a thermostat why would belt be smoking ? ?
Almost Like something seized causing belt to slip and smoke ?
Ever see this before ? Any ideas ?
 

christo829

Member
Dec 7, 2011
513
Fairfax, Virginia
nbenjamin said:
Have not been aroumd for a while so a big hello to everyone
Don't drive the truck much. But a couple days ago I used to to go to a job
Sitting waiting I notices a burning rubber smell then it some squeaking sound. At first I thought it was my fan clutch
Then I notices the engine temp up so I shut it down right away
Smoke under the hood. Checked it was coming from the belt next to idler pulley
Let it cool took belt off next day checked water pump ( spins nicely ) checked AC bearing seems ok
Power steering ok. Belt tens pulley ok. Idler pulley bearing a little rough but spins freely
At 190 000 kilometers I have changed almost everything on this truck but the thermostat
But if it was a thermostat why would belt be smoking ? ?
Almost Like something seized causing belt to slip and smoke ?
Ever see this before ? Any ideas ?

If the idler pulley feels rough when cool, it may be seizing up as it warms up. Once the belt starts
heating up, it may be slipping and causing the water pump to not get driven efficiently.

Good Luck!

Chris
 

CaptainXL

Member
Dec 4, 2011
2,445
I agree, it's the idler. Should never be rough or sound like it when spinning. I think it's a good idea to change the tensioner at the same time. Your belt is a goner as well. Time for a new one. I replaced all three of mine at almost the exact kilometers.
 

nbenjamin

Original poster
Member
Dec 7, 2011
76
CaptainXL said:
I agree, it's the idler. Should never be rough or sound like it when spinning. I think it's a good idea to change the tensioner at the same time. Your belt is a goner as well. Time for a new one. I replaced all three of mine at almost the exact kilometers.


Advise taken. Any issues with temp sensor ?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Temp sensor is near the thermostat, and should not be involved in this incident at all. The tensioner being discussed is a "tensioner pulley" of the same sort of design as the idler pulley, but it's the one on a lever arm you pull on to change the belt.
 

nbenjamin

Original poster
Member
Dec 7, 2011
76
the roadie said:
Temp sensor is near the thermostat, and should not be involved in this incident at all. The tensioner being discussed is a "tensioner pulley" of the same sort of design as the idler pulley, but it's the one on a lever arm you pull on to change the belt.

I will prob change both pulley but is it worth it to maybe change thermostat. Do they fail around 200 000 kilometers ? I have changed the water pump twice already
 

CaptainXL

Member
Dec 4, 2011
2,445
nbenjamin said:
I will prob change both pulley but is it worth it to maybe change thermostat. Do they fail around 200 000 kilometers ? I have changed the water pump twice already

Thermostats have no specific lifetime. A scan tool is used for diagnosing a bad thermostat. Usually not noticed until the CEL comes on.

As for the water pump. Make sure you are getting a quality part and make sure the fan clutch and fan is not off balance or damaged.
 

nbenjamin

Original poster
Member
Dec 7, 2011
76
the roadie said:
If you get code P0128 or the temp gauge needle isn't pointing straight up in normal operation, then think about a thermostat service. Otherwise, leave it be.

No codes. Just thought about being pro active. Would hate to have it go while on a trip or something. But if it not on te trailblazer list of things that happen at a given then I will leave it
 

CaptainXL

Member
Dec 4, 2011
2,445
You said there are no codes. How did you come to that conclusion? Did you have it scanned? Or do you have a scanner?

If you are concerned about it you can bring it to Advance Auto or Autozone and have them scan the coolant temperature. Should be in the 195-210F range with the engine running and fully warmed up. If it's in that range then it should be ok as Roadie said.
 

nbenjamin

Original poster
Member
Dec 7, 2011
76
CaptainXL said:
You said there are no codes. How did you come to that conclusion? Did you have it scanned? Or do you have a scanner?

If you are concerned about it you can bring it to Advance Auto or Autozone and have them scan the coolant temperature. Should be in the 195-210F range with the engine running and fully warmed up. If it's in that range then it should be ok as Roadie said.

I have a scan Gauge 2 I used to keep on the truck I
Put it on my civic cause it has close to 300 000 k on it. Ironically I Have never had an issue yet with the civic. I will put it back on truck tomorrow and monitor coolant temp.
 

nbenjamin

Original poster
Member
Dec 7, 2011
76
the roadie said:
If you get code P0128 or the temp gauge needle isn't pointing straight up in normal operation, then think about a thermostat service. Otherwise, leave it be.

just got the P0128 guess its time then . had no issues since changing idler and belt .
 

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