[bdozer1965]

I've had a VCMuzzler installed since the car was about a year old. I get the occasional ECO light after sitting in a hot-soak traffic situation, but it goes off almost immediately once the car is moving or the fans come up to speed to shed the excess heat. No CEL's.

The temp gauge is more an idiot gauge than an accurate indicator of coolant temp, even without the VCMuzzler installed. The actual temp range between about 180º and maybe 220ºF causes minimum gauge needle movement regardless. The VCMuzzler moves that gauge-movement range slightly. But since it has no scale, all that changes is the needle position. At the high end of the scale, the resistor adds about 10ºF to the less-responsive-needle window.

Were I starting from scratch, I'd probably choose one of the "smarter" units. At this point though I'm unlikely to change out what I have installed already. I, like a large majority of drivers, only look at the temp gauge once in a while, or when the cluster lights up and gives a high-temp alarm. That ten degree error at one (of the three...) engine coolant temp sensors is unlikely to make a difference in how I respond the gauge reading, although it will delay the temp alarms by maybe ten degrees. Critically, it does not change the fans operating temperature; that duty goes to the incoming coolant temp sensor, rather than the outlet temp sensor when the VCM defeat devices connect.

I'm using one too, around 35k miles with it and no trouble. A couple times in stop and go on really hot days the system seemed to want to engage but stopped immediately as soon as I started rolling,