Stupid, Stupid, Engine Fan Settings

[Yardbird]

What person in any capacity would think it is good to allow an aluminum engine to increase 30 degrees, then decrease 32 degrees, in a period of less than 10 minutes.

On my recent trip to the mountains, as long as I was moving well, my temp was always right at 194 up steep hills and down.

Twice I got stopped for road construction at the top of a very long and steep hill. Within less that 5 minutes the engine temp went from 194 to just touching 224 before we started moving. Oil temp went to 212, and trans went to 206.

I was at the very top both times, so as soon as we started moving it was all downhill. Temperatures were quickly dropping, with engine getting down to 190. Transmission and oil temps went down just as quickly.

I don't care who, what, or why. This is not good for an engine. Too much expansion and contraction in a very short amount of time, plus just the extreme heat in the fluids and parts.

It's ridiculous this can't be adjusted in the ECM. I guess I will just have to put in a pusher fan with a toggle switch to keep temperatures under control. I was going to last summer when I first bought the truck, but put it off.

If anyone knows a way to adjust these settings, pleas post it here.

 

[CanuckRam1313]

I would definitely consider the caulk04 transmission cooler mod, as it works extremely well for keeping our hot running transmissions cooler. I am consistently seeing a 20 to 30 degree reduction in standing and in motion trans temps at full operating temperature.

I would consider a 190 degree t-stat, and a tuner (Alpha-OBD, HP Tuners, or Diablosport) to adjust your fan settings accordingly.

Use good quality 5W30 oil and a good quality oil filter, use good quality fuel, and ensure your truck is well maintained, including fresh spark plugs.

 

[Scottly]

190 is where the thermostat is set. If your temps are going above that, the fan isn't pushing enough air for whatever reason or the radiator is insufficiently doing it's job. Have it checked. I don't think that's a "factory setting".

 

[Yardbird]

From what I've read, the Gen 4 Pentastar guys are seeing 220 on a regular basis before the stupid PWM fan kicks into high.

 

[pacofortacos]

Electric fan only on the 3.6 - and working as designed IF the fan was on hi at the 224 degree mark. If it wasn't on high you could have a bad fan. Did you hear the fan?

Only options are tune or pusher fan if enough room.

Running the AC will have the fan on most of the time and should keep temps under control in warmer weather.

 

[Yardbird]

Well, I still hate the fan settings. Drove up Beech Mtn. (NC) last week. Temp was 68. Before the top the engine temp was 2528 and flashing 230 occasionally before it started cooling, and still not under 220-224 before I topped the mountain. Shortly on the downhill side I was 194, and then 190 until I leveled out enough to get into the gas.

On the way up the backside coming home, same exact thing. These extreme temperature can not be good for any engine.

I want to add a pusher fan, and will when I can. I had a bad heart attack two months ago today, and am not able to do those kinds of things yet.

I will do something when I can, that is a promise.

(I'm picky, and don't know anyone that would install it the way I want and wire it my way.

 

[Travelin Ram]

FCA or Fiat or whomever is writing the ECM software have some weird ideas.

My 22 Jeep will under some conditions run the fan on high speed even coasting downhill in cold weather. With all fluid temps at or below nominal. High 22x is where it normally engages.

The Jeep and the PW at times will open the throttle while coasting downhill in low range. Kicks the “idle” all the way up to 3,000. That’s a lot of fun on a shelf road in the mountains.

 

[Tom Davis]

I had a bad heart attack two months ago today, and am not able to do those kinds of things yet.

Wishing a full and speedy recovery.

 

[hunterdan]

Hemi trucks with the 8 speed trans (non-rebel models) are equipped with active grille shutters. Under light loads while cruising, the shutters close to maximize aero. This will cause the temps to bump up to about 220-223 degrees. At which point, the shutters open, and the temps cool to about 199. The cycle repeats over and over while cruising under light throttle. Get heavy on the throttle and the shutters open to maximize cooling. Hemi trucks use the clutch fan with a secondary electric fan (used when the AC is locked on) in front of the clutch fan. The OEM thermostat is 203 degrees. I've deleted the shutters, replaced the stock fan assemblies with an OEM style V6 fan out of the 09-12 trucks. My temps don't exceed 205 degrees unless the AC is off and I'm sitting in traffic or idling for extended periods of time. My trans doesn't see 190 degrees, hardly ever. The trans has a thermostat opens at 180 degrees. I don't know if your truck is a V6 or V8. If you have the V8 and your temps are climbing that much, I'd start troubleshooting further. I'm not familiar with the V6 setup, but the only difference should the electric fan. Now, as for the temperature swings being bad for the motor, if there was an issue, you'd have a warped head and blown head gasket by now, and it'd be far more common of an issue, like the broken exhaust studs.

 

[Yardbird]

Wishing a full and speedy recovery.

Thanks. I'm slowly getting there. I will gain, then lose some, then gain again. The docs are saying around 6 months to go as well as I will get, which they hope is good. Not as good as before, but good enough to work if I want.

At 67, I will probably retire, even though I enjoyed what I do, but it keeps the wife and I from taking some trips, and doing thinge we like together.

 

[Yardbird]

Hemi trucks with the 8 speed trans (non-rebel models) are equipped with active grille shutters. Under light loads while cruising, the shutters close to maximize aero. This will cause the temps to bump up to about 220-223 degrees. At which point, the shutters open, and the temps cool to about 199. The cycle repeats over and over while cruising under light throttle. Get heavy on the throttle and the shutters open to maximize cooling. Hemi trucks use the clutch fan with a secondary electric fan (used when the AC is locked on) in front of the clutch fan. The OEM thermostat is 203 degrees. I've deleted the shutters, replaced the stock fan assemblies with an OEM style V6 fan out of the 09-12 trucks. My temps don't exceed 205 degrees unless the AC is off and I'm sitting in traffic or idling for extended periods of time. My trans doesn't see 190 degrees, hardly ever. The trans has a thermostat opens at 180 degrees. I don't know if your truck is a V6 or V8. If you have the V8 and your temps are climbing that much, I'd start troubleshooting further. I'm not familiar with the V6 setup, but the only difference should the electric fan. Now, as for the temperature swings being bad for the motor, if there was an issue, you'd have a warped head and blown head gasket by now, and it'd be far more common of an issue, like the broken exhaust studs.

I have a V-6, shutters removed except for top, middle, and bottom. I run up hill with the A/C on max to make sure the fan is running. I've tried hills without the A/C on, and the engine gets warm faster.

If this truck had something other than the PWM fan I could fix the problem myself rather easily.

 

[Wild one]

I have a V-6, shutters removed except for top, middle, and bottom. I run up hill with the A/C on max to make sure the fan is running. I've tried hills without the A/C on, and the engine gets warm faster.

If this truck had something other than the PWM fan I could fix the problem myself rather easily.

I'd say swap the grill,but by your avatar it looks like you already have the better flowing honeycomb grill,so there's no gain there.

 

[turkeybird56]

I'd say swap the grill,but by your avatar it looks like you already have the better flowing honeycomb grill,so there's no gain there.

But U know, the friggin Hemi's are no better. Since I got the 1st year 5th Gen, there were a few burbs. Mine will go down to 199 then spool up to 212, then go down to 203, then back up to 210, sometimes even higher, and that is just "regular" driving. as most know, the AC on the new 5th Gens suks. But I will say, running at 80 mph on IH 35, is the best time for the AC and temps, as they all stayed in stock range and I had to actually turn up the AC temp from 60-65. That sure as heck not happen often. I am running stock with shutters, as dis BOIRD not normally drive far.

ADDED: Sometimes, I actually put the AC on MAX to spool up the fan when parking at house, and idle for a few secs till temps come down. The OP is correct, whomever designed all these temp settings and codes in the computer controls I believe NEEDS PROFESSIONAL HELP, lmao.

 

[hunterdan]

But U know, the friggin Hemi's are no better. Since I got the 1st year 5th Gen, there were a few burbs. Mine will go down to 199 then spool up to 212, then go down to 203, then back up to 210, sometimes even higher, and that is just "regular" driving. as most know, the AC on the new 5th Gens suks. But I will say, running at 80 mph on IH 35, is the best time for the AC and temps, as they all stayed in stock range and I had to actually turn up the AC temp from 60-65. That sure as heck not happen often. I am running stock with shutters, as dis BOIRD not normally drive far.

ADDED: Sometimes, I actually put the AC on MAX to spool up the fan when parking at house, and idle for a few secs till temps come down. The OP is correct, whomever designed all these temp settings and codes in the computer controls I believe NEEDS PROFESSIONAL HELP, lmao.

It's efficiency. And those temps are normal even for the hemi. Seeing 230 degrees is excessive, anything up to 223-234 is normal. Read my post above how the system works. If there was a flaw in the system. You'd see more warped heads and blown head gaskets. But we don't. While the temps may seem high, and aren't the best for PERFORMANCE, from an efficiency standpoint, 200-215 is acceptable.

I'm all for having as much information as possible, especially for diagnostics, but in some cases, having too much information available can make people freak out and over analyze.

 

[hunterdan]

FCA or Fiat or whomever is writing the ECM software have some weird ideas.

My 22 Jeep will under some conditions run the fan on high speed even coasting downhill in cold weather. With all fluid temps at or below nominal. High 22x is where it normally engages.

The Jeep and the PW at times will open the throttle while coasting downhill in low range. Kicks the “idle” all the way up to 3,000. That’s a lot of fun on a shelf road in the mountains.

Wat you're seeing isn't the throttle opening and "idling", it downshifts into a lower gear to use engine braking. Doesn't hurt anything, and if you're off the throttle, the fuel should be cut so no heat going into the motor other than friction.

 

[hunterdan]

I have a V-6, shutters removed except for top, middle, and bottom. I run up hill with the A/C on max to make sure the fan is running. I've tried hills without the A/C on, and the engine gets warm faster.

If this truck had something other than the PWM fan I could fix the problem myself rather easily.

The pwm isn't the problem. The pwm just means the computer can control what rpm/how much cooling it calls for, instead of having just low, medium and high speeds. Again, seeing temps up to 224 or so is normal (at least on the hemis) V6 might be higher. But if you're seeing temps of 230, then either you're not moving enough water through the motor, or the radiator is not transferring heat efficiently enough. At speeds over 35-40 mph, there should be more than enough air passing through the radiator that the fan isn't needed. The fans are really only needed at low speeds.

 

[1 MEAN66]

IF IT IS A 190-degree thermostat. That is the temp at which the thermostat STARTS to open, Not the temp the computer systems will keep the engine temp at! there also is a "bypass" system to keep water circulating at ALL times. There are even "high flow" thermostats vs standard (OE) flow. Radiator water gets hotter so do the other fluids. Remember even with extra coolers added your trans fluid goes through a cooler "inside" the radiator. That is why extra coolers should be after than fluid leaves the radiator. Normal trans fluid, normal operating temp should not be far under 180 degrees. 240 degrees of water temp. can sometimes be considered "design normal". So, what is the design normal of your vehicle? Do you have a shutter system? If so sounds normal. If not, is it still "normal".

 

[Travelin Ram]

Wat you're seeing isn't the throttle opening and "idling", it downshifts into a lower gear to use engine braking. Doesn't hurt anything, and if you're off the throttle, the fuel should be cut so no heat going into the motor other than friction.

No, that’s not correct. These vehicles have tachometers and gear indicators.

Shift to neutral when it’s happening and the engine will continue to run at 3k and gradually slow down to normal idle again.

 

[Yardbird]

The pwm isn't the problem. The pwm just means the computer can control what rpm/how much cooling it calls for, instead of having just low, medium and high speeds. Again, seeing temps up to 224 or so is normal (at least on the hemis) V6 might be higher. But if you're seeing temps of 230, then either you're not moving enough water through the motor, or the radiator is not transferring heat efficiently enough. At speeds over 35-40 mph, there should be more than enough air passing through the radiator that the fan isn't needed. The fans are really only needed at low speeds.

The stupid programming is the real problem. Since I can't change that, a non-PWM fan would allow me to run it to a separate thermostat, or hook up an on-off toggle switch so I could turn the fan on when I want to. Probably do both, if I could.

 

[Travelin Ram]

I would think Alfa OBD or HPtuners could access the set points for the fan control algorithm. One of these days I may find the time to dig into that. I’d set the fan about ten degrees f cooler if I could.

(On the Jeep; the PW has an engine driven fan)