I have an '07 V8V with about 34k miles. On a recent trip I noticed it was having trouble getting up to operating temp in about 55 degree weather. After researching here (great resource) I replaced the thermostat, but that doesn't seem to have fixed the issue. The coolant temp still sits at about 1.5 tick marks below normal operating temps (i.e., the gauge sits between the 7 and 8oclock positions). No CELs or other warning lights are triggered. Any ideas what else could be causing low operating temps?

 

I would get a scanner or elm327 Android dongle, to check the actual temp your ecu is reading..unless your fans are locked on full speed all the time from a faulty fan module..its going to be either the stat again or something which I've never seen like a faulty sensor/module/wiring, causing this issue.

I've had quite a few ppl say the same thing.."I've replaced the stat but still temp doesn't reach operating"..90% turned out to be either a faulty stat again(either not installed correctly, center pin pulled out, seal offset again). I know the stat job is a P.I.T.A, but if your operating temp isn't reaching 90C on a scanner read..I would investigate the stat again and replace it if needed again.

 

Thanks Irish!

Following up on this in case anyone comes across this thread at a later date. The stat appears to have been incorrectly installed as I had another installed and the operating temp problem is solved.