My 2003 Durango 4.7l is overheating not on cool days only hot days, sitting at idle, stop and go traffic, or heavy acceleration. Cruising at highway speeds or coasting helps to cool it down, also turning off a/c. Checked about everything, down to thinking it's a head gasket or cracked head, read somewhere you can take the radiator cap off and rev the engine and if it blows like old faithful it's a head gaskets. Wanted to know if there's any truth in this before I tear the engine apart. Any help would be appreciated.

 

Are you losing coolant? If a head or head gasket is the issue yes you will put pressure into the cooling system but I have not heard of it coming out like ole' faithful just bubbling with the cap off (not revving it).

 

A head gasket generally will give your exhaust a sweet smell if it is burning antifreeze as well as a white smoke. Check your fan first if you havent already. It could be an electric fan not turning on or a bad clutch in the mechanical fan depending what yours has. What you described sounds like the air is not moving across the radiator unless you are driving which leads me to suspect a fan issue.

 

 

Mine has a mechanical and a electric fan both have checked out, there is no oil in my coolant or coolant in the oil, I'm not losing any coolant. It does have constant small bubbles that come up while at idle and when revved up it shoots out. I'm stumped. I've never had a head gasket, or head act like this but I'm out of other options. Air moving across the radiator helps unless your pulling a hill or heavy acceleration. I'm out of ideas and pulling my hair out. Oh and nothing out of the exhaust. Aux. water pump also working.

 

Going to run a compression, and a bled down test now to see what's going on in the cylinders.

 

Sounds kinda like a clogged radiator had similar problem cures it with new radiator

 

Is you water pump working?

 

Water pump is circulating, once the thermostat opens you can see it clearly moving in the radiator hose. Compression test ranged 123-127, bleed down test ranged from 8-14%. So definitely don't think it's a head gasket. Inside of this engine seems to be in great shape. Has anyone had any experience with the auxiliary water pump causing overheating? If it is radiator, do they make bigger aftermarkets for these 4.7 engines? Thank you all for the feedback.

 

Currently I don't think they make an oversized radiator.It does not take much to partially clog one of these up mine looked good and clean but when i used infrared thermometer on it could see cold spots replaced it and all good ever since.