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I have an 07 LVS and the running temperature seems to be right around 180 on mid-summer days. Is this normal? Also, when I am at idle speed the temperature seems to go over 180 briefly until I get going a bit more than idle speed, then it comes down. Could this be an impeller issue?
You running a little hotter then you should.
You should be right at 160 most of the time.
It could be an impeller, it could be a stuck thermostat. Its probably stuck half half to 3/4 open, I would lean more towards the thermostat because technically when impellers start to fail, the fail completely and you overheat.
I agree with mmandley that you should be around 160, but I've been through thermostats and impellers on ours and it always runs a needle or two below 180 on the gauge. I haven't investigated the sensor or gauge and finally just accepted this as our normal operating condition.
My 07 LSV runs dead on 180 and has for years. At idle is actually drops a little lower. I replaced my thermostat a few years ago just out of precaution and the temp stayed the same. You could change the impeller and the thermostat just to be safe, especially if you don't know when they were last done. They aren't too expensive or hard to replace either one.
The impeller is only effective at low speeds so any speed while on plane would be hydrostatic pressure and the water flow would just be a pass through the impeller assembly. If the temperature rise occurred while at idle then the impeller could be suspect.
Freshwater cooled engines run considerably colder than their automotive counterparts as they are receiving a continuous supply of fresh cold water. However, a warmer running engine will perform better and be more efficient than a cooler engine. Your typical automobile engine runs between 195 210 degrees.
The optimal operating temperature for the GM vortec is between 200-212 degrees.
However, I would definitely check/replace your impeller to prevent a catastrophic failure. In addition, check with enginenut on the forum here.
I’ve actually considered swapping my thermostat to a 180 degree stat.
Definitely check with enginenut!
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I have run a needle below 180 as well for years. I removed two elbows from my water intake and it runs a few degrees cooler now.
It is normal for the engine to briefly go over the thermostat temp when it is brought down to idle due to the heat sink nature of a hot engine and the short lag response time in tstat increasing its opening. Mine does the exact same thingQuote:
Originally Posted by Aondion