I have a 2004 Dodge Ram Quad Cab with a 4.7L V8. Recently my truck started running hot while in traffic and will fluctuate back and forth from halfway on the guage to halfway between middle and over heating. I took it to the Dodge dealer today and he could not tell me for sure what the problem is, but he "thinks" it is a blocked radiator and wants to charge $500 to fix the problem. A couple of questions I have:

1. Would a sticking thermostat cause the flucuation in temperature? When the truck is past halfway on the gauge, I removed the cap and the fluid level inside the cap was to the top (as well the resevoir is in normal range). Shouldn't there be some movement in the fluid if the Stat is open and circulating the fluid?

2. It gets even hotter when pulling my boat. This has never been a problem in the past. Anyone else have this problem? Can a blocked radiator fluctuate temperature or does it stay hot?



Someone please help! I am a my wits end with this.


2004 Dodge Ram Quad Cab

4.7L V8

Volant Air Intake system

flowmaster 40 series muffler

Lawrence

 

Get your coolant in the radiator checked for emissions.
If there's polutants in your coolant, it could be a cracked head or blown head gasket.
They take a sample of your coolant with a hydrometer like tool with chemicals in it that change colour if there's emissions in it.
It's quicker (2 minutes) and cheaper, than a full coolant flush and will tell you, if there's any serious damage in the engine.
Al.

 

What you are describing could be a thermostat. It's a simple fix - a gallon of coolant and a $10 thermostat. How many miles are on the truck? I wouldn't think an 04 would have a blocked radiator yet but who knows. Are you using the red coolant?
Or if you want to do a quick check, put your current thermostat in a pan of boiling water and see if it opens.

 

Have you or anyone else changed the coolant recently? Or anything else for that matter.

 

The truck has 41,500 on it. I am using the red coolant.

 

I think the dealer is trying to take advantage. The thermostat opens and closes, and I can't think of a normal instance where you should be able to SEE the coolant actually flowing. First of all you shouldn't have been able to remove the radiator cap on a hot engine without a shower of hot antifreeze. I'll bet a simple coolant and thermostat change will fix the problem.

 

Sounds like the thermostat, it's an easy replace. Rec getting a failsafe replacement that will go to full open if it fails. Stant makes a good one.

 

I don't recommend the failsafe stat until you've solved the overheating problem first.
I installed one on a friends minivan once. When it overheated, the stat permanently locked open. Had to replace it even though it wasn't the cause of the overheating (low coolant, due to small leak in hose).

 

Roger JRH, I agree with you that a failsafe could complicate diagnosing some coolant problems. For the most part though, a failsafe will let you get home or to a shop where you can fix the problem. If a regular thermostat fails completely it will close and you will overheat. A tstat failure usually means you have to pull over now, wherever you are, or risk doing permanent damage to your engine. If a failsafe goes bad then your engine will just run too cold.

 

I'd just flush the coolant and swap in a new thermostat.