O'K Went on a 70 mile drive, 40 miles highway, 30 city stop and go. E-fan removed, only clutch fan operable. Went 52 miles, 40 highway, 12 city, overheated gauge pegged, red light came on at 52 miles, stopped refilled with water, drove 13 miles home. Only went above 2500 RPM in lower gears, max 5th gear RPM APPROX 17-1800. No visable water leaks, but, did put almost 2 gallons in at 52 miles. the 3.9 Dakota system holds 15.3 quarts, so, almost 4 gallons. The water is going somewhere. Did not see vapor from the exhaust. I dunno, I'm stumped. PS spent 10 bucks on a new safety release rad cap to reduce grief.

 

Put a pressure tester on the cooling system and look for leaks - such as the bypass hose behind the water pump.

Also, run the engine until it's hot and look for the gauge to "pulse".

 

Ok this may sound stupid ... how's the engine oil level and when was it last changed with a new oil filter?

 

I'm back at it. I reinstalled the bench tested factory fan which I direct wired to the battery with no relay. Cranked the truck, turned on the A/C, and ran up to temp. At first all was good, then the fan slowed down to almost nothing, and, made 'bad' noises. Even after cooling down the fan would not operate up to speed. So, I bought a used after market 16 inch fan with controller from a friend. I've ordered the mounting kit from Amazon so it will be a few days. My question is how do I hook it up? Relay or not. It has to be switchable to the ignition, but, as you know the fan is always on when the A/C is on. BTW the guy I got the fan from had taken out his clutch fan and said that his 5.9 ran just fine with A/C on with the temp controlled e-fan. I did a pressure test last week, it revealed no problems, however, if I continue to have probs after I get the e-fan working I will re-rent the pressure tester. I just want to solve the e-fan thing then move on. Any suggestions?`

 

Well I like OEM unless you really need something better non OEM always create problems of their own.

So I'm guessing you are saying the stock fan is defective/Bad.

Why not go simple get a new OEM fit fan its plug and play as they say?


Removing the clutch fan is not advisable it can work but that depends on where and how you drive a lot of city stop and go would not work so well as your not moving air past the rad as well as needed now if doing a lot of freeway driving great your moving lots of air past the rad.


A replacement efan runs about $90

 

Well, I agree, but, (lol). I'm not positive that the factory wiring is working properly because I could never get the factory fan to work wired up OEM. Then again it could've been just the defective fan, even though it worked on the bench it failed miserably installed, and also, I got a whack of a deal on this aftermarket fan and controller. I have zero interest in removing the clutch fan even though with the e-fan on it does make a noticeable difference in the amount of sound. It does get really loud. I can understand some of the younger members wanting to quiet it down, (I.E. sounds like granny's car), I am not in that group. I just want a truck that my kid can drive, and me too occasionally that doesn't overheat. If this doesn't go well I will get an OEM fan and move on from there.

 

I may sound negative but you're barking up the wrong tree for now. If you had to add 2 gallons of water you are losing it somewhere. Find/fix that first. No matter how well the fan runs if you don't have coolant it won't cool the engine.

Did you look for a relay in the PDC for the fan? It may have failed, especially from the way you're describing the fan motor acting.

Relay or not? You'll have to describe your plans in more detail. The existing fan does not run through the ignition switch. From the battery it runs through a relay that is controlled by the PCM.

 

I agree find out why you are losing coolant first that's potentially a dangerous problem.


Did the new rad cap fix that?

 

I lost coolant because it blew the plastic connector on the engine side of the fill cap tee which seperated the hose losing all coolant. I replaced that with a standard hose clamp. Now, I agree that this may not solve all my problems, but, if I get all systems operating as they should that would mean less variables for me to get to the actual problem, if any, other than a bad e-fan with the A/C on. I dunno, we will see.

 

Well, I've replaced the thermostat and the cap, they are working as they should. When I get the fan mounting kit I will bypass the PCM and connect to an ignition on circuit. I swapped the relays initially, but, the fan may have been in such bad shape that that was not a definitive test. But, since I already have this new fan I'm going to wire it in. After that it can only be, from easiest to hardest, 1) blocked radiator, I've already backed flushed to no advantage, both upper and lower rad hoses are warm to touch after the thermostat opens, the upper more so than the lower, 2) bad water pump, I have one on the bench waiting to go on if all else shows no improvement, 3) blown head gasket, cracked heads or block, unlikely because pressure test suggested all was well, but, if all else fails, that is the logical conclusion. Ps, I drive it everyday to take my wife to the store. A distance of about 10 miles round trip. I sit outside idleing with the A/C for however long she decides to be in there, which can be an aggravatingly long time, up to an hour, then I drive home, no overheating, no heat gauge needle wavering, no coolant loss, but go 50 miles stop and go, I'm toast.