2002 Dodge Ram 1500 Quad Cab 4.7L

First off my truck has never overheated before or even thought about it.
I took my truck in to check the heat because it was not working. They suggested a flush and fill of the heater core and refill of the radiator fluids. I got that done and heat started working again. I drove 9 miles home and everything is fine. So then I drive 25 miles to work today and about 20 miles down the road the truck is overheating. Check Gages light is on and temperature is pegged. Antifreeze is boiling when I get there, steaming out the cap. I can feel it boiling in the pipes and radiator. It did cool down when parked.

They said when they did the work that I should replace my radiator cap. Could that be the cause of all of this or other suggestions? Things done wrong or causes?

Any help would be good, I have to drive back home.

 

it is possible the oxalic acid in the 'Flush' has caused part of the thermostat to crack

it is less likely to be the radiator cap
but many of the auto parts stores have a tool to pressure test those for free,
so call around

good luck

 

if the cap isn't sealed right, the coolant will boil easier, so that may be it, but you would see steam/liquid coming out of it. If you don't see any of that, probably not the cap.

they might just not have filled it up all the way when they were done with it. see if you can put some more in there. Overheat with some coolant in there and no steam says to me it might not be full all the way. A bad thermostat would do it too though.

 

Thanks,
I did check the level of the coolant when it cooled off and it was to the fill line. They suggested a new cap because when I brought it in it was low and had signs of steam around the cap. Still it has never overheated before.
I ran it a round a little while ago for 15 minutes and the temp went to half way and stopped.
I am going to stop and get a new cap this afternoon no matter what. If it gives me a problem may go put a new thermostat in. Could it run fine at times and not other times with a bad thermostat?

 

You need a thermostat.

When they fail it's frequently in the closed (or semi-closed) position. Yours is probably stock and it's time for a new one.

Sometimes as the tstat fails you will notice the temp going past mid-way before going back down to normal. The temp starts going higher each time until finally the tstat is dead and you overheat.

Once you see the needle pass half-way, STOP DRIVING. A maxed temp gauge can mean engine damage, all over a $5 part.

 

Hey Atlanta 29,
I own an 02 4.7L and I have had overheating problems with here recently that just popped up out of nowhere. I have installed a new radiator cap, thermostat, water pump, and had the radiator flushed and refilled. My truck still overheats occasionally (whenever it feels like it), but now it seems to only run hot when I DON'T run the heater. The last thing I can think of to do it buy a new radiator, and if that doesn't fix it I'm trading it in.
SOMETHING TO TRY...There is a valve to bleed the air out of the system, it is an allen wrench bolt that you loosen till the pressure is relieved, and it is located where the coolant comes back out of the engine into the radiator. Careful not to loosen it while the system is overheated, mine shot out so hard it could have put an eye out.
If you figure something out, PLease let me know. GOOD LUCK!

 

Sounds like an air pocket to me. Find out how the shop refilled the antifreeze. My son uses a vacuum system at his shop to refill and never has an air pocket, and never has an overheat after a flush/fill.

 

Could be an air pocket or the scale buildup has broken loose more while you were driving and it is now blocking the inlet tubes of the radiator. You might want to consider re-treating and flushing again, and put a new stat in.

 

OK put a new thermostat in and new cap and still does the same thing, overheats.

This stinks.

By popular demand we are going after an air pocket in the morning. I will keep an update on what happens.

 

So here is an update so people who read this will have an answer. In all I ended up replacing the radiator cap, radiator reservoir tank, thermostat, Fan clutch and radiator. Finally that fixed it. Problem with each. Radiator cap had a bad seal, radiator reservoir tank had a crack near the top, thermostat failed, Fan clutch was working but really slow, not doing much and Radiator was clogged up really bad. Fan was moving but not much now it is flowing air through the front. The radiator was hot in the middle and cool around the other areas, so something to check. Also when we drained the radiator after truck was running the fluid coming out was cold for the first 10 seconds then got hot. Indicator that was not getting good flow. Hope this helps someone in the future from not having their truck sit in the shop as long as mind did.