winter front, fan, coolant temp gauge.

[Killer223]

installed winter front on my 04, left one flap open, proceeded to drive to town, about a 12 mile trip. most up hill.

anyhow about 4 miles in the temp gauge was reading 120, but the fan clutch locked up like in a high heat situation. it cooled off some, another mile or so later temps up to 140ish, again fan locks up. 

so after my trip to the paint store, i opened 2 more flaps, head 3 miles away to sons school, fan locks in again and tempos are just barely 180. 

 

i'm reading temps on the dash and the edge. they both read close to each other. 

Trans temp never above 140, 

 

i guess questions would be, why is the fan locking up? temps from what i can see don't warrant it. so i'm at a loss. ida thought that the winter front would help, but if the fans gonna be in lock up all the time it'll negate the mpg gain i'm hoping for. 

this trucks has always taken FOR EVER to get warm. no matter the t-stat installed. 

i can drive from flagstaff to sedona from my house it's about a 32 mile trip, and it'll never get to temp. stays 140 ish. even worse if i have to run the heater. 

yet i can start it and drop into gear at idle, and i'll be warm in 5-7 min. but idling kills mpg's. 

[Tractorman]

3 hours ago, Killer223 said:

ii guess questions would be, why is the fan locking up? temps from what i can see don't warrant it. so i'm at a loss.

 

Possibly what is going on is that you have disrupted the engineered smooth, laminar air flow through the AC condenser core, CAC core, and radiator core . 

 

If very little air can enter the fan intake area, then very little air can leave the fan exit area so the temperature in that immediate area may rise fairly quickly and the thermo-sensor in the center of the fan hub will engage the fan.  Once the fan is fully engaged, it will generate a considerable amount of turbulence and air recirculation because its air intake supply has been essentially cut off.  The engine would not have to be "hot" for this to occur and the fan may run for some time.

 

Without a winter front installed the thermal sensor in the center of the fan hub always has a smooth stream of air flowing across it - so it is very stable and engages the fan with repeated accuracy when necessary.

 

What you could try is to have at least four separate openings in  your winter front.  They should be equal in size and be evenly spaced around the perimeter of the winter front area.  The idea is to have several places for air to pass through without creating turbulence and to also have enough air flow to keep up with the fan speed when it is disengaged (the fan is always moving some air)  If you get it right, then the thermo sensor will always have a stream of air passing around it.

 

 Some of the better winter fronts on the big rigs are set up like this.

 

- John  

Edited January 4, 2018 by Tractorman

[Killer223]

Thank you for the detailed response. This is the first I’ve heard of the fan hub having a thermal sensor. I was under the impression it was all ecm controlled. I did have one flap open, tomorrow I’ll test with three open. 

Its a mopar winterfront. If that helps. 

[Tractorman]

2 hours ago, Killer223 said:

Thank you for the detailed response. This is the first I’ve heard of the fan hub having a thermal sensor. I was under the impression it was all ecm controlled. I did have one flap open, tomorrow I’ll test with three open. 

Its a mopar winterfront. If that helps. 

 

I just realized  that I gave you wrong information.  I had it in my head that we were talking about a second generation truck.  You are correct - on your truck the fan is controlled by the ECU, either when the engine temperature is high enough, or when the AC head pressure reaches around 250 psi.

 

With that said, a different but similar situation could be occurring.  If you have your ventilation setting in the defrost mode, the AC compressor will be cycling by default.  With very little air flow through the AC condenser, the ECU could be telling the fan to come on because refrigerant pressure has increased significantly. 

 

It could be a combination of both engine temperature and AC head pressure. 

 

I apologize for the confusion on my part.

 

- John

[Killer223]

Ac is off, vents were on floor. Head pressures don’t lock fan up till around 350. 

So it still doesn’t make sense to me. Coolant temps as noted were well below tstat even opening. Maybe it’s time for a new michanical gauge. 

But if the temp shown on the dash is the same one the ecm uses to. Control the fan.. I’m lost yet again. 

Frustrating.... 

[Mopar1973Man]

36 minutes ago, Killer223 said:

Coolant temps as noted were well below tstat even opening. Maybe it’s time for a new michanical gauge. 

 

I've seen some strange cluster issues on 3rd Gen trucks where the coolant gauge was slow. So the ECM could be reporting a overheat issue but the gauge still shows slightly elevated temperatures. Tachomoters that report idle speed at 400 RPM's and buries at redline at little over 2,200 RPM's. 

 

I would verify the info from the OBDII port see if the numbers are real.

[Killer223]

i have my EDGE CTS, it's temp mirrors the dash. 

[AH64ID]

Intake air temp is also used for fan control. I don't recall the parameters off the top of my head but if the IAT is enough above the AAT the fan will engage. 

 

What kind of intake do you have?

 

I have only ever had the IAT's engage the fan once. I was doing 5-10 mph on a steep uphill single lane dirt road with all 4 flaps closed and my IAT's got to around 140° with it being 25° outside. 

 

I've been driving around for the last few weeks with 3 flaps closed in temps from 12°-33° and the fan hasn't cycled once. 

 

Which flap do you have open? I leave the one open on the side by the intake/exhaust. 

 

On 1/3/2018 at 4:46 PM, Killer223 said:

i can drive from flagstaff to sedona from my house it's about a 32 mile trip, and it'll never get to temp. stays 140 ish. even worse if i have to run the heater. 

yet i can start it and drop into gear at idle, and i'll be warm in 5-7 min. but idling kills mpg's. 

 

Is this coolant temp?

 

If so you need to find what is causing the coolant to stay so cold. 

 

My truck is the coldest blooded truck I know. The cam, turbo, and coolant filter all increase warm up time and the longest I've seen to get to thermostat opening, 190°, is around 16 miles. That includes some driving in -30° weather. 

4 hours ago, Killer223 said:

i have my EDGE CTS, it's temp mirrors the dash. 

 

Which means the dash is correct, but it doesn't mean the temp sender is correct. 

 

But if the temp sender reads cold the fan should run even less. 

 

 

 

 

 

I forgot I had downloaded UDC Pro onto this computer. 

 

The stock 2004.5 tune shows that if the IAT (intake manifold) is 24° above the AAT (air intake sensor) the fan will start to ramp up. The AAT also has to be above 60°. 

 

So I would guess that you're getting some hot intake air and some hotter manifold air. What does the CTS show for IAT's? Can it show AAT's?

 

The other day I was driving to work in the low teens and my AAT's were about 2° higher than ambient and my IAT's were about 15° above that until my thermostat opened and then the warmer radiator warmed the intercooler and my IAT's were about +30° from ambient. 

 

Also.. being AZ, what are your ambient temps?

 

Over the years I have found that a winter front only has minimal impact on warming the motor up but has a big impact on it keeping temp while coating, stopped, and parked with the engine off or on. 

Edited January 5, 2018 by AH64ID

[Killer223]

i have an early 04, stock intake. ambient temps in the am around 25°. i'll have to look to see if the Edge can read those settings. 

if im harder on the truck i can get it to 140 in about 8 miles. but i rather keep my boost low, 3-5 at most. the flap i had open was top center, today i opened the top and both sides. was able to get 180 before i made it to Sedona, ambient temps when i started was 25 and 45 at destination. i didn't make note of the miles but would guess around the 15-18 mile mark. No fan action till i was heading home from Sedona and it's mostly up hill. ambient temps around 60°, coolant temps were then 210-214 and lots of fan to cool it off, got home and took winter front off the 04 and put it on the 08. 

 

i do know my stock intake no longer has the little foam between the box and fender, i've thought about using some duct tape to bridge the gap, but also thought maybe it's no that big of deal.... 

[AH64ID]

Whoops. I read early 04 and opened an 04.5 for some reason. They are slightly different. 

 

Are you taking the back roads to Sedona? That's a lot of downhill if memory serves so the time to get to operating temp might be normal. 

 

Then again if the intake is getting warm enough to trigger the fan at a 28° differential your thermostat might not be sealing and heating the radiator, which will heat the intercooler, and then the intake air with a winter front mostly closed. 

 

I'll bet the CTS can monitor IAT's, and probably AAT's for troubleshooting. 

 

The stock 2004.0 tune shows that if the IAT (intake manifold) is 28° above the AAT (air intake sensor) the fan will start to ramp up. The AAT also has to be above 60°. 

 

Initial fan rpm is set to 1200 and it ramps up 80 rpm/deg from there. The fan is commanded to max at 38°.

 

Haha...yeah 60° is a bit much for 1 flap closed. The fan kicks on at 210° ECT. 

 

My foam barrier was missing too and I was seeing higher IAT's that I was used to. I replaced it this last October but haven't towed in any heat yet to see if it made a difference. I'm pulling very cold outisde air right now thou. 

Edited January 5, 2018 by AH64ID