Hi guys, heres my problem.

I have a 2005 Express 2500 and it has recently started overheating. Im not losing coolant, and it get worse climbing any kind of hill. Yesterday i was driving on the interstate when it got hot enough i pulled over. After letting it cool down, i started it back up and drove 150 miles with no problems. Heater and ac work up until the engine gets to about 250 degrees. Also, it seems like the oil pressure is low and is fluctuating quite a lot. At idle the oil pressure is between 25-30 but when i get it up to 70mph it hold steady around 35. Van has 87k miles on it.

Any help would be awesome, thanks!

 

Which engine is in the van? Even at 70 mph the oil pressure sounds low at 35. When is the last time the oil and filter were changed?

 

A bad thermostat not fully open could cause flow issues....