Hey all, it's been awhile since I have been on the forum but I am having a problem with my 2005 ram 1500 4x4, truck has only 47,000 miles and I am hoping it is an easy fix. So after the truck is at full operating temperature, it doesn't matter if I have it set on defrost or blowing through the vents or at the feet position it will start to blow cold air and then it blows warm air again. I have also noticed that when I use the remote start and after about 12 minutes of run time, I used to be able to have a nice warm truck when I get in it, that has not been the case lately. Now I live in California and the temperature has not been that cold. I have felt both hoses going to to the heater core under the hood and they are both hot to the touch. Any ideas on this issue before I have to take it to shop, oh and the coolant has never been changed or flushed. Thanks for the help.

 

Is it low on coolant?

 

it was about 2 quarts low, refilled and will check tonight when I head out to work.
I cant seem to find any threads on how to change thermostat, can you help with link or thread?

 

What engine?

 

I have a 5.7 Hemi.
So It seems to working fine now that I have added the coolant. was getting around 135 degrees from the vents. I have not notice any leaks on the ground so I'm kinda baffled on where the coolant went to. The over-flow bottle was filled to the cold line when the the truck was cold as well. Do the Hemi's use oil as well, this truck is a 2005 with 47,000 miles on it. I run Mobil 1 synthetic and change it every 5k but it does use a quart between oil changes.

 

That's a rather short interval for oil changes. Manufacturers recommend 7,500 miles unless conditions warrant otherwise (i.e. very dusty environment). Also, using a quart between intervals is not normal. My truck doesn't burn any oil and it has 114,000 miles.

 

Well the reason I do is because I drive fairly short distances and I only put 4k miles a year on it.

 

Coolant will evaporate off. Keep a check on it. You gotta drive that truck more. Could be carbon build up causing ring seating issues.

 

Check the manual for the monthly interval, then. Overall, synthetic oil isn't like old school dino oil that breaks down and becomes acidic. It may not hurt the use it the full 7,500 miles. Hell, Porsche and GM recommend 15,000 and 25,000 oil changes in their vehicles which run full synthetic.