I had a $20 oil change coupon for the dealer and had them inspect the front suspension (just to make sure everything is okay). When I looked at my receipt it says they put 5W-20 in it. I thought this was odd since the oil cap says 5W-30 and I swore the owner's manual said the same. So I checked my physical owner's manual and it says 5W-30 and so does the filler cap. I have downloaded the owner's manual from Dodge and it says to use 5W-20. I kinda find it odd they contradicted, but I heard they changed it for the '07, even though I have an '06.

So now it's really hot in Tucson this summer looking at over 100 degree temps... truck's overhead temp gauge can say it's up to 117 when I've started it. It seems to be getting warmer than normal even with the 180 degree T-stat in there.

So my questions are could the difference between 5W-20 and 5W-30 make that big of a difference with the engine's temperature, and should I be using a higher viscosity of oil (just the hot viscosity) since it's so beastly hot? Should I put synthetic in there instead?

Thanks in advance.

 

I went through some 120 deg plus days back when I lived in AZ. My old F100 used to run hotter during the summer. I just tried to monitor things and do my best to stay out of stop and go traffic. Cleaning the bugs out of the radiator seemed to help some.

 

Yeah I probably need to do that too... I'll have to break out the pressure washer... haven't cleaned the radiator since it went to TX.