I have a 2005 envoy xl with the inline 4.2. We have a small camper we tow with the envoy and in the middle of summer when it’s really hot the envoy will creep above 210 degrees sometimes when towing. Will a aux radiator fan help or is there something else I could try?
Envoy inline 4.2 aux fan help
- Thread starter Kylek
- Start date
Mooseman
Moderator
Check that your fan clutch is working:
How to test the electro-viscous fan clutch
But really, 210 isn't that bad. As per the fan engagement chart, at 210, it's only engaged at 7%, which means it's not that hot. At 221 though it starts to really pull so that's when you start keeping an eye on it. 230 is where it really kicks it up at 39-56%
What kind of weight are you pulling? Are you towing in OD? If it has any kind of real weight and it makes the tranny shift down constantly, this is an indication that you can't tow it in OD and should tow in 3rd gear. This constant shifting creates extra heat that will end up in the radiator and adds extra wear to the clutches. Even if towing in 3rd, an auxiliary tranny cooler will help with both heat and tranny longevity.
As for an aux fan, it would be useless as the stock fan is able to pull as much air as a dump truck's.
How to test the electro-viscous fan clutch
But really, 210 isn't that bad. As per the fan engagement chart, at 210, it's only engaged at 7%, which means it's not that hot. At 221 though it starts to really pull so that's when you start keeping an eye on it. 230 is where it really kicks it up at 39-56%
What kind of weight are you pulling? Are you towing in OD? If it has any kind of real weight and it makes the tranny shift down constantly, this is an indication that you can't tow it in OD and should tow in 3rd gear. This constant shifting creates extra heat that will end up in the radiator and adds extra wear to the clutches. Even if towing in 3rd, an auxiliary tranny cooler will help with both heat and tranny longevity.
As for an aux fan, it would be useless as the stock fan is able to pull as much air as a dump truck's.
Hey Mooseman... I know that you have indicated the "operational sematic" associated with the electrical based fan clutch but was wondering if the "temperature ranging" is similar for the thermal based clutch in terms of "clutch pressure / grip" at 210 versus higher as you have indicated or is the thermal clutch more coarse / gross with basically an "ON / OFF position" only. Wondering about the "degree" of turn on.Check that your fan clutch is working:
How to test the electro-viscous fan clutch
But really, 210 isn't that bad. As per the fan engagement chart, at 210, it's only engaged at 7%, which means it's not that hot. At 221 though it starts to really pull so that's when you start keeping an eye on it. 230 is where it really kicks it up at 39-56%
What kind of weight are you pulling? Are you towing in OD? If it has any kind of real weight and it makes the tranny shift down constantly, this is an indication that you can't tow it in OD and should tow in 3rd gear. This constant shifting creates extra heat that will end up in the radiator and adds extra wear to the clutches. Even if towing in 3rd, an auxiliary tranny cooler will help with both heat and tranny longevity.
As for an aux fan, it would be useless as the stock fan is able to pull as much air as a dump truck's.
Mooseman
Moderator
I would imagine the thermal is more coarse in its engagement adjustments and would also be dependent on the aggregate of the ambient and generated heat for the RPM obtained. The thermal fan would likely not engage as much at 220 in the dead of winter vs the dead of summer heat. In the electro-viscous' controls, the PCM actually uses desired fan RPM according to engine temps only (and A/C high side pressure). In the scan tool, there are parameters for desired fan speed and actual fan speed.
The electro-viscous fan idea was a good one to allow it to truly freewheel when it's unneeded however has proven to be failure prone and problematic, which is why GM went with the thermal in '08-09. I still have the EV in my '07 and as long is it's still working, I'll keep it however a thermal is ready to go in as soon as it fails.
The electro-viscous fan idea was a good one to allow it to truly freewheel when it's unneeded however has proven to be failure prone and problematic, which is why GM went with the thermal in '08-09. I still have the EV in my '07 and as long is it's still working, I'll keep it however a thermal is ready to go in as soon as it fails.