Does anyone know if coolant temp sensor on 2006 envoy(4.2l) should be about 10° cooler then dash gauge reading when car is warmed up and idling in park. Dash gauge shows 210 (right in the middle) but scanner shows my coolant temp sensor reading stays at 199 when warmed up...( and drops 10° more when driving)... my thermostat was no good recently..(temp gauge would stay at 165ish when warmed up).. new thermostat brought it back to correct temp.. but the coolant temp sensor shows 10° less.. they both warm up at the same rate from cold..but once they hit 175°ish..the coolant temp sensor gets hotter much more slowly then the other sensor in engine which feeds computer which feeds dash gauge (gets to 210) ..while coolant temp sensor takes an extra 15 minutes of idling to get up to 195-200°... is this 10° difference normal? ..my 2006 envoy the coolant temp sensor is not next to thermostat anymore..its located on other side of the engine block. Any info ir help us greatly appreciated. Thx!
2006 Envoy - coolant temp sensor question
- Thread starter Gballs
- Start date
xavierny25
Member
Mike534x
Member
- Apr 9, 2012
- 1,003
199-206 is roughly the normal temp range for the I6 when warmed up. The coolant temp sensor is pretty cheap, no harm in replacing it if it makes you feel better. Like Xavierny mentioned, the gauges aren't accurate on these trucks. My temps hover within 199-209 when warmed up (5.3), but my gauge never reads straight up and its off by 2 ticks to the left of center. Now when I had my spare cluster in it would read straight up dead center on 210.
I know its not the most accurate, but since it was reading 165-170 with a bad tstat and when i swapped it brought it back to 210 (no changing..always stays within that hashmark even if it slightly moves ..(not to mention my cluster makes a bunch of the ticking noises at times, gonna have the clusters cleaned or replaced anyway).. the main reason I ask about the difference in temperatures is because a few months ago I changed my water pump and fan clutch.. and was working fine... then like 2 weeks ago my cousin and it up putting in a bunch of green coolant mixed with my Dex Cool and a few days after that it would take a lot longer for my fan clutch to disengage after the cold start... it pretty much was on point with my Dash gauge(clutch would disengage when car hit 210 mark and drove it for 1 minute and when hits 2nd gear disenages) until this coolant mix. Now i have to wait an extra 15 minutes of warming up after dash hit 210 so coolant temp sensor gets to 190-200 before clutch will disengage.. I think with our models the coolant temp sensor has to hit 190 or something like that for the computer to send the signal to the fan clutch to disengage( and I know with the new fanclutch that the fluid inside has to warm up so that it can work correctly and with new ones sometimes it takes longer but it was working the same way like the old one the first two months I had the new one installed and just changed after this mix of coolant. I did drain some of it out but I'm sure there's probably a half a gallon or so still in there.. I'm wondering if that can be an issue causing the coolant not to warm up enough or if it messed up the sensor.. I do have the new sensor but when I changed the t-stat I realized it wasn't next to their anymore and seems like a real pain to be able to get to it in the back of the engine block I can barely even see it(any advice on how to attack that change would be great also).. anyway sorry for such a long explanation just wanted to give you guys the full story..
xavierny25
Member
That's right the 06 still had the plug in fan or aka electro-viscous fan clutch. There is an FAQ from @Mooseman about how to test it if and when the time comes to look it over.
The better option would be to replace it with the thermal fan clutch like some have and I do on my 08. But what's done is done and if it's working fine let it be.
STOP AND FLUSH out whatever is in there and replace with dex-cool. That is going to be a costly mistake to run it with that mix even if you think it's only just a little. I had an experience where a quick lube place top off my range rover with the wrong coolant and the overflow tank exploded.
Hold off on replacing the temp sensor it could wait. I have a spare in my bag of goodies for the Voy for when the time comes. I've got over 185,000 miles and so far the sensor is doing just fine.
The better option would be to replace it with the thermal fan clutch like some have and I do on my 08. But what's done is done and if it's working fine let it be.
STOP AND FLUSH out whatever is in there and replace with dex-cool. That is going to be a costly mistake to run it with that mix even if you think it's only just a little. I had an experience where a quick lube place top off my range rover with the wrong coolant and the overflow tank exploded.
Hold off on replacing the temp sensor it could wait. I have a spare in my bag of goodies for the Voy for when the time comes. I've got over 185,000 miles and so far the sensor is doing just fine.
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xavierny25
Member
2 things could be going on here. It's either the steeper motors are on there way out or it could be the hvac blend/temp motors back there causing all that racket.
xavierny25
Member
Mooseman
Moderator
The inacuracy of the gauge is called "filtering" by GM. The PCM will lie a little when it's running at it's normal temp between 190 and 200, it will show 210 straight up just to not alarm the driver. If it is truly too low or high, it will show it though.
Thx guys..
Never heard of the GM filtering thing... dont really mind the temp difference if its normal, but seems like something changed the rate of temp increase on the coolant temp sensor after the green fluid was put in... before the mix, it used to increase same rate as dash gauge until it hit 200..now it slows down at 185ish while dash gauge continues to 210.... I have 95,000 miles and don't want to do a full coolant flush cause im sure the dex cool already is all gunked up in my radiator and such..and dont want to loosen globs of stuff that can get caught and flow and get stuck elswhere in coolant system (buddy did the same and ended up with more issues cause he caused clogging and other issues that way..) I guess I will do a drain and fill... and hopefully its not the fan clutch viscosity causing the delays in disengagement...even though it was worki g fine the first few weeks till the coolant mix happened..
Never heard of the GM filtering thing... dont really mind the temp difference if its normal, but seems like something changed the rate of temp increase on the coolant temp sensor after the green fluid was put in... before the mix, it used to increase same rate as dash gauge until it hit 200..now it slows down at 185ish while dash gauge continues to 210.... I have 95,000 miles and don't want to do a full coolant flush cause im sure the dex cool already is all gunked up in my radiator and such..and dont want to loosen globs of stuff that can get caught and flow and get stuck elswhere in coolant system (buddy did the same and ended up with more issues cause he caused clogging and other issues that way..) I guess I will do a drain and fill... and hopefully its not the fan clutch viscosity causing the delays in disengagement...even though it was worki g fine the first few weeks till the coolant mix happened..
Yea..i definitely think the stepper motors are the noise...(same noise as i heard before on a friends which was stepper motors)...but all gauges working fine..will get to that at somepoint.(I used to smoke, so im sure smoke residue is making the rubber on stepper motors sticky..)(heard that from someone else..who knows but sounds logical)
So you are saying you know "exactly" when the "slow down" occurs (ie. 185) which you can obviously monitor with live data. Then, have you checked to see when the fan clutch circuit has been de-energized as opposed to "I think"? Have you tried swapping the fan relay to see if there is a difference?
One other thing, the fan isn't only "governed" by temperature of coolant.
One other thing, the fan isn't only "governed" by temperature of coolant.
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Apologies for some of my wording...I am not trying to act like i know the exact data to the tee.. It just kept disengaging at that range 185-190. No I havent checked the circuit voltage or swapped the relay yet (been super busy last few days..hopefully during Easter weekend I will get a chance)(Which btw, May you all have a Happy Good Friday, Easter and Passover!!!). I truly appreciate all the time and info everyone is sharing on here. My buddy has a scanner that will be able to tell me the PCM command being given to the fan clutch, so compare the engine rpm, fan clutch rpm, and pcm rpm instruction to the fan on how much fast it should be turning, so can see if thats in sync or if issue there... and as you said, other things also control the fan clutch (another issue I will post a new thread about (I am running lean a bit). I did randomnly notice this morning when i cold started, the clutch did not engage, but then randomnly engaged after 15min. while still idling and engine was already warm. I didnt do anything (like giving gas, or turning on air,etc) and went away few minutes later, a minute after i started driving. So that has me wondering now about the issues you mentioned.. fun times!
Great crew of people here! Glad to be a part of it! Thx all!
Great crew of people here! Glad to be a part of it! Thx all!
No problem... I am just trying to get as much info from your "eyes" as possible as I can't really see thru the internet well... 
NOTE: The Fan control is not only an "ON/OFF"... there IS fan speed involved. Hopefully, your access to a scanner will help but in a "pinch" a regular multimeter will help.
NOTE: The Fan control is not only an "ON/OFF"... there IS fan speed involved. Hopefully, your access to a scanner will help but in a "pinch" a regular multimeter will help.
Mooseman
Moderator
The chart on the fan command is located here:
gmtnation.com
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