If you look at my signature my truck is far from stock. I was going down the road and all of a sudden my temp Gage went to 240 and my heater quite. My first thought was head gasket. Then the temp would go back down to normal. I pulled over in a Covent spot and popped the hood no leaks no white smoke and the radiator over fill jug was at a normal level. But what I thought was strange was the radiator cap was cold. Truck did the same thing one more time before I got home.

The whole problem is the radiator was about 3/4 a gallon low on water. I have put about 500 miles on since filling the radiator and have had no problems. I have no leaks the reservoir jug is still on the full line. At this point I am not sure why water isn't going from the reservior to the radiator.
Just thought this info might interest some of you and prevent trouble down the road. -

Hummin Cummins's Sig:

2006 blk 3500DRW, Smarty,TST,Dynatrac free spin, Pac Brake,South Bend DD3600, Firestone airbags, Transfer Flow toolbox/50 fuel tank combo
Rollin on 6 aluminum Freightliner style 22.5's
ATS 3000/5000 twins, ARP Studs.

Need a new cap. -

wildbill's Sig:

I Drive An 06 Dodge Ram 2500

Powered By a 5.9 Cummins

It Has Some Parts But Could Use More

96,000 Miles

Big Sky Bombers Social Group

Yup, a bad cap that does not seal correctly will not create pressure to suck water into the radiator... Even though NAPA products are good, go straight to Cummins for a new cap. Should only be about $10. -

TXAustin's Sig:

04.5 Cummins- 6" superlift on 37" Procomp A/T, DC-1 rims, rebuilt at 103,000miles, BD Super B Special turbo, BD exhaust manifold, Head Studs, Edge juice with Hot unlock, 90hp nozzles, AIR DOG 150, 6" MBRP stacks, AFE filter, 12000# smittybuilt winch, Ranch hand, built tranny, Lock up switch

Really a Radiator cap I can afford one of those -

Yeah its nice when you find out it's a cheat fix! -