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Overheats when running the A/C, but only when idle

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alexrv1

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Discussion starter · #1 ·
I was wondering what you guys think the problem may be. It started last summer, after the water pump was replaced. I did replace the thermostat about 6 months ago, but the problem still exists. If the A/C isn't on, I can idle in all day long with no overheating. But it only takes a few minutes of running the A/C when I'm not moving and the temperature starts rising. While I'm driving, the temp lowers again.

99 - 5.2L
Flowmaster Exhaust
Bilstein Shocks
K&N FIPK II
Hypertech 180 Thermostat
 
#2 ·
Does the rpm's go up at idle with the A/C being on? It should rise by about 250 rpm's.

The 99's had a marginal radiator at best, and overheat if you look at them cross-eyed. The only real fix for overheating on the 99 is an electric fan conversion. It'll also improve the A/C at idle speeds. I have done the v-10 fan-clutch conversion, and it helps but doesn't solve the problem.

An electric fan will pull much more air at idle/slow speeds than the mechanical fan is able to do. This will cool the engine and increase the cooling ability ofthe A/C as well.
 
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Discussion starter · #3 ·
Hmmm?since its been cool here in SoCal, haven't used the A/C lately. But I do believe the RPM went up slightly. My local mechanic suggested a radiator replacement. Is there a better aftermarket one I can purchase? Also, where can I find info on the electric fan conversion? Oh?and?THANKS!
 
#4 ·
When you're moving, the air flow from the motion provides much of the air flow across the radiator for cooling. At idle, the mechanical fan is all that you have is the mechanical fan. The AC condensor throws off a lot of heat so at idle it'll really tax it. I'd start with replacing the fan clutch.
 
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#5 ·
I have the mechanical clutch fan AND an electric fan mounted to the engine side of the radiator. I also have three radiators, progressively smaller in size, one normal Coolant Radiator, one as the Oil Cooler and one as the Transmission Cooler. The electric fan is used anytime the AC is on and who knows when it comes on at other times. I do have the heavy equipment and tow package.

Is that (having a factory electric fan AND the mechanical clutch fan) somewhat unique to my D (tow group/heavy equipment add-on only) and not normal on all D's?

IndyDurango
 
#6 ·
I have the mechanical fan and a smaller electric fan as well. My build sheet says "NMCP - Heavy Duty Engine Cooling", I assume this means the additional electric fan as part of the tow package, but not sure. I was told by a mechanic that the electric fan only operates with the A/C on, but don't know if that's true, will have to wait for warm weather to find out.
 
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#7 ·
The 98/99's only had the engine mount fan. If you're going to change the fan-clutch, use the one from the v-10 engine and it's fan. It'll get rid of the cold start-up fan noise problem that plagued the 98/99 D's annd seems to pull more air. It won't completely cure the heating problem, but it'll lessen it. Mine would overheat at idle in @ 5 minutes with the A/C and 85 degree air. Best cure is a total electric conversion. This also gives you a few extra horses as you're not having to urn the fan with the engine.
 
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#9 ·
All 2000 and up Ds have both Mechanical and electric fans as well.
Steve
DOC Pres
 
#10 ·
IndyDurango said: Is that (having a factory electric fan AND the mechanical clutch fan) somewhat unique to my D (tow group/heavy equipment add-on only) and not normal on all D's?

Hi IndyDurango; My D with the 4.7, also has this setup as part of the heavy duty/tow package configuration. This is an add on package to the base D configuration. When I bought my D in December, the original 2001 Data Sheet was in with the owners manual so if it'd be of any help I can post this to show how the packages were broken down for my model. Let me know.

Canuck "D" :D
 
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#11 ·
As Stevenoted, all 2000 and up Gen-1's have both the electric and mechanical fan, in all configurations.

There's an official DC kit available to add an electric fan to 98/99 Ds, but it's fairly expensive and a lot of work (lots of stuff gets relocated, and some models also get a new alternator)?

the "fan TSB" (fan clutch etc) helps some, but not really enough? I still had to be careful when stuck in traffic on summer days in my '99?
 
#12 ·
On my "Price Information" sheet for one of the Tow Package options it states Engine Cooling - Heavy Duty. What parts does this statement apply to?

Canuck "D"
 
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#13 ·
Transmission cooler
 
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#14 ·
Thanks for your reply Neil, but my price sheet lists the T-cooler and Power Steering cooler separately.

Canuck "D"
 
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#15 ·
FSTDANGO3 said:
All 2000 and up Ds have both Mechanical and electric fans as well.
Steve
DOC Pres
Click to expand...
I have a 2004 DD with the 3.7 V6. Only has a mechanical fan. I'm having the problem as well with running hot when I turn on the AC. Sometimes it gets hot even when I'm not depending on outside ambient temp. Sometimes I have to open up the heater to bleed off the heat, and that can be oppressive where I live (N. TX).
Especially now. I've swapped the thermostat. Seemed to help a little.
I don't even know how to swap the fan clutch. I can't figure out a way to get the fan shroud off as it covers the fan and extends almost all the way to the front of the block.
I've considered an elec. fan conversion, but I've not done anything like that. Don't know how difficult it would be.
Could the AC being low on refrigerant make the motor run hot, if the compressor is working too hard, perhaps?
Any one of you have an ideas?
I'd love to hear some input on this.
Thanks.
 
#16 ·
The AC has nothing to do with the viscous drive fan clutch. You might have a bad fan clutch, or maybe old coolant, low coolant, air in your cooling system, a clogged radiator or condenser coil, collapsing radiator hoses, etc.
 
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#17 ·
Tin Foil Hat said:
The AC has nothing to do with the viscous drive fan clutch. You might have a bad fan clutch, or maybe old coolant, low coolant, air in your cooling system, a clogged radiator or condenser coil, collapsing radiator hoses, etc.
Click to expand...
Tin Foil Hat said:
The AC has nothing to do with the viscous drive fan clutch. You might have a bad fan clutch, or maybe old coolant, low coolant, air in your cooling system, a clogged radiator or condenser coil, collapsing radiator hoses, etc.
Click to expand...
New coolant, radiator is not clogged because I checked that first, replaced radiator hoses. Replaced radiator cap too. Not sure what the hoses would have to do with this anyhoo, but they are new.
Only things not new is fan clutch and condenser coil.
 
#18 ·
Dave Beavers said:
New coolant, radiator is not clogged because I checked that first, replaced radiator hoses. Replaced radiator cap too. Not sure what the hoses would have to do with this anyhoo, but they are new.
Only things not new is fan clutch and condenser coil.
Click to expand...
Does it overheat only at idle, or while you're driving? If it's at idle it's most likely a fan issue, if it's while driving it's possible your water pump is going out.

1949 International KB2, 302/T5
1968 Dodge Dart GTS, 340/727
2006 Dodge Magnum R/T "SRT Design"
2016 Dodge Durango Limited
 
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