Hurricane cold start high idle and operating temp questions

[az_sst]

I took delivery of a '25 quad cab 4x4 with the Hurricane 3.0 two weeks ago and have questions relating to two issues. Firstly, the high idle time with a cold engine seems excessive to me. At relatively warm ambient temps (80'sF), and a cold engine, the engine will idle at 1500 rpm for ~1.5 mins before dropping to 600-700. At slightly cooler ambient temps (60-70's) the high idle at cold start can be as long as 5 mins before dropping down.
The second issue is with the operation of the radiator cooling fan. At highway speeds, or with the AC on, both coolant and oil temps stabilize at 195-200F. At slower speeds and with the AC off the coolant temps approach 220F before the fan kicks on, and it stays on only until the the temps drop slightly to 212-214F where it turns off again, and the cycle repeats. When it does turn on at the higher temps it is not running that fast (not as fast as with the AC on). It seems to me that it should be moving as much air as possible at those temps.
Just looking to other Hurricane owners for their observations and experiences. Are these behaviors normal or is something wrong with my truck? Thanks.

 

[Biga]

The idle time is consistent with what I have scene on my truck. Honestly, I have not paid much attention to the coolant temp. but I will try to keep an eye on it and let you know.

 

[MT755]

I'm guess the engineers want the engine temps and catalytic converter temp up quickly to reduce emissions. Maybee?

 

[az_sst]

Well I answered my own question. A review of temperature related threads in the Hemi sections of this site show a lot of descriptions of the same operation if not hotter: fan comes on at ~220F and off at ~210F with AC off, coolant temps run ~205F with the AC on. I'm calling it normal operation for now although I might go with an after-market PWM fan control for towing to lower the temps a bit. It seems the manufacturers like to run these modern engines at temps that make us old-schoolers a little squeamish.

 

[J-Cooz]

Well I answered my own question. A review of temperature related threads in the Hemi sections of this site show a lot of descriptions of the same operation if not hotter: fan comes on at ~220F and off at ~210F with AC off, coolant temps run ~205F with the AC on. I'm calling it normal operation for now although I might go with an after-market PWM fan control for towing to lower the temps a bit. It seems the manufacturers like to run these modern engines at temps that make us old-schoolers a little squeamish.

I'd say just leave it. Modern engines run hotter, it's completely fine.

Sent from my SM-S911W using Tapatalk

 

[el-zilcho]

Wagoneer 3.0 owner here, mine has the same long idle warm up time, however, mine has the hd tow package with upgraded cooling and while towing 6k enclosed trailer my oil or coolant temps never topped 212. Be on the lookout for failing thermostat housings, it's starting to become an issue because they are plastic.

 

[motomarc]

My truck has almost 1000 miles on it and yes high idle at start is crazy and lasts about 1 minute or more.
I looked at temps the other day and was surprised as well it runs around 200-215 from when I looked. oil psi around 20-25 have seen go up when hit throttle.
I will pay more attention over the next few days.

 

[SD Rebel]

I took delivery of a '25 quad cab 4x4 with the Hurricane 3.0 two weeks ago and have questions relating to two issues. Firstly, the high idle time with a cold engine seems excessive to me. At relatively warm ambient temps (80'sF), and a cold engine, the engine will idle at 1500 rpm for ~1.5 mins before dropping to 600-700. At slightly cooler ambient temps (60-70's) the high idle at cold start can be as long as 5 mins before dropping down.
The second issue is with the operation of the radiator cooling fan. At highway speeds, or with the AC on, both coolant and oil temps stabilize at 195-200F. At slower speeds and with the AC off the coolant temps approach 220F before the fan kicks on, and it stays on only until the the temps drop slightly to 212-214F where it turns off again, and the cycle repeats. When it does turn on at the higher temps it is not running that fast (not as fast as with the AC on). It seems to me that it should be moving as much air as possible at those temps.
Just looking to other Hurricane owners for their observations and experiences. Are these behaviors normal or is something wrong with my truck? Thanks.

Well I answered my own question. A review of temperature related threads in the Hemi sections of this site show a lot of descriptions of the same operation if not hotter: fan comes on at ~220F and off at ~210F with AC off, coolant temps run ~205F with the AC on. I'm calling it normal operation for now although I might go with an after-market PWM fan control for towing to lower the temps a bit. It seems the manufacturers like to run these modern engines at temps that make us old-schoolers a little squeamish.

Your thermostat temp range seems to match that of the 5.7L Hemi, except the fan on the Hemi usually doesn't turn on until 230F, and stops at 220F. Looks like the Hurricane is designed to run a little cooler, at least with fan activation.

Modern engines are designed to run hotter for best power and efficiency, at least that's what they say. The days of 180F is long gone, where today running "cool" is about 205-210F.

 

[delsonrun]

Has anyone experienced rough cold starts when an engine RPM fluctuates slightly during the first 15-20 seconds? My 2025 Laramie does this every single cold start. None of the cars / trucks I owned ever did that.

 

[LOWRMPG]

Interesting article talking about the temp at which fuel vaporizes being one of the primary reasons for a high idle. Would make sense on a motor boosted so high. Seems like a high idle mod on a diesel.

Why does an engine's idle RPMs take time to settle from a cold start?

I've noticed my car's (healthy) engine will idle at a slightly higher RPM for a few moments after it's been started from cold/not run for a day. I also noticed that my (somewhat less healthy) othe...

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