Hi all,

I live in East Africa and have a 2003 SLT Dodge Durango 4.7 V8. Obviously, this is a US spec car that I brought here for my two year assignment in the region. I have had the car since new. Today, it was 108 F outside and the car's temperature went to "H" and the check gauge came on. I pulled to the side of the road and let the engine cool down. Once it was cool, I added liquid into the overflow, while running the engine. I was missing about half a gallon. On the way back to the city, when I drive at around 60 miles an hour, the temperature remains a little over the middle mark, but as soon as I slow down, it goes up to the "H" mark. This happened two times on my 45 mile trip back. Always getting hot when I am at a standstill or going slow. After arriving home and having the car sit for three hours, I start it up drive for about 4 miles without any problems (about 103 F outside). Even when I slowed down or just let the car idle, not overheating. I am baffled. Someone suggested taking out the thermostat as it may have become stuck and therefore not allowing any coolant to the engine. Any thoughts on this? Any help would be much appreciated. By the way, the fan seems to be running fine. I can order parts from the U.S. but there are no good dealers around here. Thanks!

 

my first check would be the fans (yes plural)

you have a clutch fan which should spin all the time, however when the engine heats up it should spin faster, the way the clutch works is that it 'freewheels' the fan when the engine is cool, (the fan still spins, just much slower than the engine it turning) and then locks up as the engine heats up. when the fan engages you WILL hear it making an awful lot of noise, if you didnt hear this your clutch is probably bad.
You can check the clutch by spinning the fan by hand(push one of the blades) with the engine off, if it spins more than 1/2 a turn your clutch is shot, if it doesnt spin at all (once you let go of the fan) the clutch is siezed (i doubt this is your problem) if its somewhere in the middle you are fine.
For reference my fan spins about 1 blade when pushed by hand

next check your electric fan, it should be in front of the clutch fan, and should be on in 2 cases,
1) if the a/c is on,
2) if the engine gets above a certain temp (i believe it is 210)

you should check it with a flashlight while the engine is running and the a/c on.


the other thing you need to do is to bleed the cooling system to make sure there is no air in it (there probably is right now since you were 1/2 a gallon low on coolant)

also wash off the radiator good with a hose and make sure there are no bugs or dirt blocking air flow through it.


I rule out the thermostat bc if that was stuck the truck would overheat all the time no just when you stop

 

Thanks! I will check first thing tomorrow morning when I get some daylight. I did notice though that after I got home and the car sat for 3 hours and when I used it again and it did not overheat the loud fan came on. Not sure if I heard it when it overheated the first couple of times. Any thoughts on why it would not run sometimes and then run again later? Is this the normal why it fails?

 

my fan clutch is bad im changing it on friday but sometimes it works most of the time it doesn't

 

even if the clutch is bad it might 'work' when the truck is first started after sitting because all the fluid has settled to the bottom and until it gets properly distributed the clutch will be grabbing, these clutches are known to do that on cold starts after sitting for a while