I've noticed that whenever the truck reads 100F+ outside, the engine only puts out (what feels like) 60-70% power and the clutched fan is 100%. So say if you were taking off (even half throttle, but definitely noticeable at WOT) from a stop on a hot summer day, there is a definite power loss, and the truck is noisy (the 'blowing' sound from the fan) as hell.
other times when it's not that hot the truck is fine. anyone else have that? i swear i read in here somewhere that a bully dog can correct that (although not exactly advisable apparently). it's not that the truck is overheating, the gauges show normal (slightly less than 1/2) temperatures.
this happen to any one else? help finding that other thread with that info would be appreciated too (i'm still looking, just can't seem to put in the right keywords)
summer/heat power loss
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doctahjones
- Posts: 844
- Joined: Tue Nov 16, 2010 11:08 am
- Location: aurora, co
The fans come on as a result of either high ECT, or the AC blowing, there are different stages. But if it's that hot outside, the ECT is most likely really warm, and the AC is on, so that would satisfy the scenario that both fans are "full blast".
Also, the gauge is really just an indicator, it will read the same level when the ECT reaches operating temp, and right before a problem ECT occurs, typically around 160ºF - 220ºF.
Just seems like typical heat soak to me. Pretty sure there's nothing that can be done bout it.
VQ35's are some of the worst I've ever seen. The VK56 actually accounted for this problem in having a large oil capacity, and larger cooling jackets, and the intent was to help when towing. I don't think it's as bad though. It was 105 last weekend, and I definitely noticed she was acting a bit strange/sluggish.
Also, the gauge is really just an indicator, it will read the same level when the ECT reaches operating temp, and right before a problem ECT occurs, typically around 160ºF - 220ºF.
Just seems like typical heat soak to me. Pretty sure there's nothing that can be done bout it.
VQ35's are some of the worst I've ever seen. The VK56 actually accounted for this problem in having a large oil capacity, and larger cooling jackets, and the intent was to help when towing. I don't think it's as bad though. It was 105 last weekend, and I definitely noticed she was acting a bit strange/sluggish.
Though it doesn't get as hot in my neck of the woods, I did tow my humungous camper in some 100-110F heat a few weeks ago. I had my Superchips Cortex plugged in, and when coming to a stop, the ECT spiked to over 210F. I assume this is because there is a large heat load on the engine, and little to no coolant flow when the engine rpms are at idle.
I noticed no degradation in performance, and the temp gauge on the dash never moved. (Its a dummy gauge anyways, which is why I use the Cortex).
The fan clutch on our rigs is a viscous fan clutch, the fluid becomes more solid as the temperature increases, thus causing the clutch to engage harder, causing less slip and higher fan speed. I don't think I've ever gotten to the point where I heard the electric fans kick in other than for AC.
One would think that if the engine was derating, that it would provide some warning on the dashboard, or a code of some sort.
I noticed no degradation in performance, and the temp gauge on the dash never moved. (Its a dummy gauge anyways, which is why I use the Cortex).
The fan clutch on our rigs is a viscous fan clutch, the fluid becomes more solid as the temperature increases, thus causing the clutch to engage harder, causing less slip and higher fan speed. I don't think I've ever gotten to the point where I heard the electric fans kick in other than for AC.
One would think that if the engine was derating, that it would provide some warning on the dashboard, or a code of some sort.
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