Overheating Durango, I give up!

[Hootbro]

Originally Posted By: morris
you drill the hole between the gasket serface and the part that moves. the hole is just there to let the air out and let the coolant in. you have to be patient. allso i have used 100% antifreeze . the thing is it freeze about -3o or -70 iam not sure. but it doesnt freeze hard, just mushy. so in kansas iam mostly ok.


Never use 100% straight up antifreeze unless it is an emergency. Highest recommend mix ration is 70% antifreeze and 30% water.

 

[occupant]

A lot of suggestions here and a lot of them make sense. Some, they don't. But I have a few ideas and I'll be back for some more info later. Right now I have a good list of things to check and I'll have all weekend to do them. But first, I need some tools.

 

[occupant]

Originally Posted By: dwendt44
How about changing the coolant sensor?
They go bad too.

Another possibility, install the largest radiator available for that vehicle.
The large size Durango could be had with the hemi engine.
The early version had the 360 as an option.


I really would like to do this, and if this radiator which is now out of warranty would just crack, I could pull all the bits I need from a '98-'99 model with rear air and a 360 and a tow package and go with that. Two problems with that idea. 1) the fan clutch for that is WAY thicker so say goodbye to my brand new thermal clutch. 2) the fan clutch is thicker and there won't be room for my brand new $200+ electric fan. I need to make it work stock first. Then when some of this stuff breaks again I can consider the '98-'99 setup with no electric fan.

Originally Posted By: eljefino
I like the ground idea. Was reading about a bad ground screwing with the PCM on these.

Try this, it's crazy: Connect a scan tool OR connect pins 4 & 5 on the OBDII port. (Signal ground and chassis ground.)

There have been durangos of about your vintage getting very wonky due to a marginal PCM ground. If nothing else it might help the logic of the electric fan come on sooner.


Is this something I can do with a multimeter? Voltage drop of more than what signifies a problem? 0.5v? 0.1v?

Originally Posted By: doitmyself
Is it possible the replacement water pump is defective? Sometimes we overlook the obvious in the zeal to "CSI" the problem.

I googled "durango overheating problem" and there are numerous links to pursue.

At Edmunds, their is a long, current thread going on that has many ideas: http://townhall-talk.edmunds.com/direct/view/.f0dfe3f This will get you into the end of the discussion, but check earlier pages too.

Topics that came up: Durangos have a 2nd. auxillary water pump??????

Bad thermostat location/design????? And many other ideas. The auxillary water pump replacement fixed the problem for many that did the same repairs repeatedly like you.

Please keep us informed!


I am certain the water pump is working well, cold engine, radiator cap off, you start it and fluid moves a bit and then when the t-stat opens it's a real good flow.

I think that 2nd water pump is for rear auxiliary heat on models equipped. My truck doesn't have this option, only rear air, but I am going to see if I have one of these electric pumps. If it's on the truck, it's probably not inline with the rest of the cooling system due to the bypassed heater core. I could always run the heater core lines back around the engine and utilize this electric pump and just not attach it through to the heater core. Re-bypass the heater core to include the pump. Hmm. Would make sense.

Originally Posted By: mopar_monkey
i've seen many issues with aftermarket fan clutches on these engine, it seems that many aftermarket clutches just don't work right out of the box.


Mopar clutch. Mopar fan. Replaced at the dealer by a dealer tech. Warrantied, even. You can def. HEAR this fan on startup, when warm, when accelerating, etc...and if the hood's open and you rev the engine it's a big wind. Also another poster mentioned is the electric coming on, and you bet it is, I have verified electric fan operation both with AC on (it stays on) and with AC off (comes on a couple minutes after t-stat opens on a cold engine).

Gearhead, I have my own compression tester and this is part of that list of things I mentioned above to do.

Flacoman, this may be the excuse I need to buy an IR thermometer and find out where the hotspots are.

Warstud, hooking the core back up isn't something I want to do, if only to avoid a wet carpet inside. Besides, with a loss of pressure I risk boilover even with good coolant mix. You have to have the pressure to raise the boiling point, too.

Skid, you know what, this fan DID look different after installed by that dealer. The question is, is it backwards now? Or was it backwards before? Or am I seeing things?

meep, I'm going to the impound auction in the morning. 27 vehicles to choose from. One is a '99 Sunfire with keys, title, good tags, good inspection. That might be a good beater to bang around town in. Also, I'm willing to put my bet on that front AC expansion valve. Why? Because it's probably shoved up in the dash with the heater core where I can't get to it.

Originally Posted By: Hokiefyd
If you run the front A/C in recirc mode, does it cool better and/or not heat the engine up as much?


Kind of and not really. I can barely notice a temp change when on MAX. Have to have the windows closed to feel it. The engine will heat up just the same. Been doing that over the last 24 hours and it gets just as hot and the AC up front still doesn't cool very well. For as cold as the back gets, it's weird that the front doesn't.

morris, I'll check this thermostat and see if it has a weep hole...it's been changed a couple times now, Texan4Life, and there's a definite "it's not opening...you sure? yeah, nothing, shouldn't it have opened by n....oh...look here, it's open now, quick put the cap back on before my wife sees this mess on the driveway" kinda thing going on.

Bladecutter, if the AC is pressurized too high, wouldn't the lines freeze up and have frost on 'em? Or is that for a low charge?

 

[lexus114]

Originally Posted By: Hootbro
Originally Posted By: morris
you drill the hole between the gasket serface and the part that moves. the hole is just there to let the air out and let the coolant in. you have to be patient. allso i have used 100% antifreeze . the thing is it freeze about -3o or -70 iam not sure. but it doesnt freeze hard, just mushy. so in kansas iam mostly ok.


Never use 100% straight up antifreeze unless it is an emergency. Highest recommend mix ration is 70% antifreeze and 30% water.



That`s right! your not supposed to use 100% antifreeze (unless it`s the already pre-diluted stuff)

 

[morris]

why?

 

[occupant]

Originally Posted By: morris
why?


Antifreeze and water work together. It's like milk and chocolate syrup. You can drink straight milk (water) and it's fine, but ice cold milk isn't any good when it's frozen. You can't really drink straight chocolate syrup (antifreeze), and neither can your engine. 100% antifreeze doesn't have the heat transference that water does. I think that's the word for it.

 

[Hootbro]

Originally Posted By: occupant
Originally Posted By: morris
why?


Antifreeze and water work together. It's like milk and chocolate syrup. You can drink straight milk (water) and it's fine, but ice cold milk isn't any good when it's frozen. You can't really drink straight chocolate syrup (antifreeze), and neither can your engine. 100% antifreeze doesn't have the heat transference that water does. I think that's the word for it.


Also, anything above a 70% pure antifreeze ratio, there is no more heat transference efficiency.

Ethylene Glycol, the main part of antifreeze, is actually a pretty poor conductor of heat and is mainly to keep the freezing of the water portion of the mix. The water is what is actually moving the heat through the system and allowing it to be cooled through the radiator.

70-30 mix is really for far North locales. In most places, a standard 50-50 mix is all you need.

Not 100% certain, but I also believe to high of a antifreeze percentage is not good for the system internal and maybe to stringent to the alloys used in the cooling system,

I think if you read the bottle of 100% antifreeze, it never recommends 100% and only to go as high as 70-30 % ratio with water.

Might also explain part of the OP's cooling issue.

 

[Warstud]

Originally Posted By: morris
why?


Because it gels-up and wont flow. Guy at work tried straight anti-freeze in his car one winter. And when he left work one night.... it was about 10-15 degrees outside and he ended up burning up the motor.

 

[ltslimjim]

When the car starts to overheat or even just idles at full temp, do the coolant hoses feel cool or hot?

 

[wander2039]

Can't offer any advice but our Festiva is doing the same. Everything looks good and is working from what I can tell. It runs about 10 degrees higher than the Aspire in the same conditions. The Aspire does have a bigger radiator but stock the Festiva it shouldn't run as hot as it is. The AC works good regardless though. I know it's running hot since the fan is coming on.. the Aspires has never came on and yes it works. I'm wondering how much the trans would affect temps. I can't say for sure but it seems like it's run hotter since I put a high dose of MMO in the auto trans.. like I said can't remember when it started I could be wrong.

 

[johnsmellsalot]

Have you tried changing the antifreeze and thermostat? Also, when your AC is on, the radiator fans should also be on, regardless of engine temp. You might want to check that out.

 

[MJB09SRT8]

I know current T-stat temps chrysler likes to use is 203, what is it for that year, with a 203 t-stat my normal coolant temps are around 210, also most replacment t-stats from mopar have the hole with a toggle in it to burp air before the t-stat gets up to temp to open.

Montrose

 

[dakota99]

That is indeed weird. My dakota with the 318 never runs hot, heck it barely runs warm. Thermostat is a 195, and cruising it usually runs around 198. In town it might creep up to 201-202 but then the clutch fan kicks in and brings it quickly back down to 197-198. I've actually never seen it past 206 driving even in hot weather with a/c on. The clutch fan never lets it get hotter.

 

[440Magnum]

Late to the thread, but my money's on either a bad coolant temp sensor, OR an air-flow problem. My folks have a 2000 Durango 5.9, and it would decidedly overheat (more than just 210, which is high but not "abnormal" if it stabilizes there) and it was the viscous fan clutch. There were several subtle cooling system variations on these trucks- some HD and 4x4 trucks had mongo heavy-duty viscous clutches but no electric fan at all, the more standard-duty 2WD layout had more normal sized viscous clutches and an auxiliary electric fan directly in front of the engine-driven fan. My folks' truck had the latter, and I never liked it- when the electric fan isn't running, its just an obstruction in the way of the engine driven fan. When it IS running, it isn't enough to cool everything all by itself. Basically, both fans HAVE to be working right to stay cool with the AC on in hot weather and slow traffic. Your guess about dead bug guts in the evap core may also be true. Have you tried pressure-washing it at a car wash?

If it were my truck, I'd first replace the temperature gauge sending unit and re-connect the heater core (318s have a separate bypass rather than using the core as the only bypass, but having the heater core in the loop often makes things just work better). If that doesn't help, I'd investigate the viscous fan clutch a little more. If I could *hear* the engine it when its hot, I could probably tell you by ear if the fan clutch is working or not- the fan should make a pretty loud roar at anything about 1500-2000 RPM, and be audible at idle except when stone cold. I've seen lots of fan clutches that pass the "spin by hand" test (they won't spin more than a blade width or two) but still don't couple hard enough to really cool the engine under load.

Your guess about dead bug guts in the AC condenser may also be true. Have you tried pressure-washing it at a car wash? I wouldn't worry about trying to back-flush it.. just blow the dead crunchy bits on through and let them fall out the bottom between the evaporator and radiator.

FWIW, I've very, very rarely seen a 318/5.2 blow a head gasket, or even have one leak. Its not impossible, but statistically its way down the list of possibilities, IMO.

Good luck with it

 

[rslifkin]

Yeah, head gaskets are rarely an issue on those engines, but not impossible. Mine currently has either a leaky HG or slightly cracked head and pushes a little air into the coolant.