Howdy Y'all, hopin to see if someone can help me verify the stuff a dealer is telling me. 2002 Dodge RAM 1500 4.7L V8. Started having this problem where when I start it in the morning to warm up, come back in five minutes or so and the heater is still blowing cold air. Water Temp is up around the middle of the gauge, but no hot air. when I start off driving it, I can feel the heat come up, but when I stop a traffic light, it starts blowing cold again. Had this looked at once and was told that the radiator cap had a crack in the seal. They replaced and filled up with antifreeze and problem went away. Now about a year later, same issue.

took it to a 5 Star dodge dealer. They tell me that the fan clutch isn't spinning the fan as fast as it should which is making it where the radiator isn't cooled correctly. Which, in their estimation, is making the radiator overheat and i'm losing coolant. But I don't see any, and the gauge doesn't ever go much above midway on the dash. Then they tell me that there is a blockage in the radiator which is causing the lack of heat in the truck. When I hit the gas and increase RPM's, the water pump pushes coolant past the blockage and that's why I can feel heat. They want me to replace the radiator, thermostat, flush the engine and replace the fan clutch....to the tune of about $1,000. They did find the truck low on coolant, so its going somewhere, but its not a head gasket blow because I have compression across all cylindars and there's no oil in the coolant or vice versa. So I tend to believe their diagnosis, but sure seems like if I was overheating the engine, it would have thrown a light or shown the gauge hot...something!

Anybody ever seen this? Any ideas?

Thanks in Advance.
Rowdy

 

Not saying that it IS your problem, but it definitely would cause your problem, so they are probably right. However, a radiator is a relatively easy install. You could purchase a new radiator for your truck for well under $200, a thermostat for about $8, fan clutch for about $50, add some anti-freeze and do it yourself in a couple of hours in the driveway. Or, better yet, screw the fan clutch and yank the fan and replace it with an e-fan for about $200 and have yourself a nice mod at the same time that will be more efficient and free up some valuable engine horsepower. The e-fan will not only get more of the engines HP to the rear wheels, but should get you about 1-2 more mpg fuel economy, mine did...

 

Possible, but the truck isn't overheating, so no.

[sm=icon_rofl.gif]

If your radiator had a blockage, you'd be overheating under load and your heater would be even hotter. Heater core gets coolant whether the thermostat has opened and allowed flow to the radiator or not.



Simple answer. The heater core is the highest point in the system, thus the first component affected by alow coolant level. Doesn't have to be very low, as the heater core only holds about a pint and a half.

And compression tests don't reveal head gasket failureunless they're really gone.

 

almost sounds like an air lock try running it with the rad cap off for a bit and see if it burps out a bunch of bubbles .

 

i think your 5 star dealer is full of bull and plans to clip you for about an extra $900.

heat delivery to the cab depends on several things working.
1. engine temperature up to normal, about 180-200 degrees.
2. water pump circulation.
3. heater core circulation (not stopped up).
4. heater/ac controls working, including blend door and fan.

the story fed to you by the dealer has all this wrong with it.
1. the job of the fan is to cool the engine. if that was not happening, your truck would overheat.
2. same with radiator.
3. thermostat maintains engine temp at 195 degrees. if this was bad your truck would be either too hot or too cold. if your temp gauge holds steady around 195, your t-stat is not bad.

its very likely that all you need is a flush of the block, radiator, and heater core, especially a back flush of the heater core which is likely about 1/2 stopped up. this should cost $50-100.

 

HEATER CORE has my vote as the problem

 

Well first they found it low on coolant, were did it go? this is why you have no heat at idle because it's not flowing through the heater core. I would do a pressure test and to find out, probably a water pump or the rad leaking. If the rad was blocked you would overheat, and not have a lack of heat. This is the same with the clutch fan if it wasn't working you would probably overheat at idle, so you would be blowing out lots of hot air. I think you just have a leak fix it and you will be fine. they are full of ****.

 

try the simplist way first, flush your coolant system. You can get a lil kit at autozone for under $10