Truck runs hot when idling - 5.7l hemi

[Lifted2wd]

2015 hemi 5.7l 160k on it

Runs hot at idle and then normal when driving. It will surge RPMs too. All this started after getting the lifter work done.

I replaced my coolant temp sensor... nothing

Also ac gets warm when this occurs

Next water pump or thermostat

 

[Tim Garceau]

Supplemental fan doesn’t kick on until 223 stock tune. How hot is your coolant getting?

 

[Lifted2wd]

240°

 

[Travelin Ram]

Air in the cooling system?

 

[Lifted2wd]

Air in the cooling system?

Thats what I thought but couldn't get any air bubbles or airpockets

 

[46RamMan]

May sound silly but is the fan belt turning the water pump pulley the correct direction ? Mayby the belt is not threaded correctly being a serpentine style.. If the pump is turning backwards it would not pump the coolant through the motor at idle..

 

[Tim Garceau]

At 160k it might be time to start doing PMs around the belt loop(idler pulley)if you didn’t when the top end was off.

110 degrees outside damn, I’m miserable when it’s 90 in Wisco. Tstat on mine is starting to stick after a year(Stant 180), replacing with a Milodon 180.

 

[Lifted2wd]

I didn't even think about the serpentine I'll pull up a diagram.

It doesn't seem consistent which is frustrating. And when accelerating it sounds like it's under massive load off the line and a fan is going full speed

 

[RedSRT4Me]

replace the thermostat and radiator cap.

 

[Lifted2wd]

replace the thermostat and radiator cap.

I have the thermostat. New cap replaced 2 months ago w the radiator

 

[PoMansRam]

Even though they still seem high, those operating temps may not be far off if it was legitimately a 110degF day.

Given the a/c works, but gets warm leads me to believe you've got a cooling fan issue going on w/ the clutch fan or E-fan. Could be other things as well, like a condenser coil and radiator fins could use a good cleaning with a hose.

If this truck has the 8spd, I believe 250F is the danger zone for ATF temp, where the fluid degrades rapidly. I haven't seen mine go beyond 180-185F on a 90deg day yet for ATF temp on my 2019 classic. Engine oil temp always runs the hottest on mine once she's up to temp.

 

[Lifted2wd]

Even though they still seem high, those operating temps may not be far off if it was legitimately a 110degF day.

Given the a/c works, but gets warm leads me to believe you've got a cooling fan issue going on w/ the clutch fan or E-fan. Could be other things as well, like a condenser coil and radiator fins could use a good cleaning with a hose.

If this truck has the 8spd, I believe 250F is the danger zone for ATF temp, where the fluid degrades rapidly. I haven't seen mine go beyond 180-185F on a 90deg day yet for ATF temp on my 2019 classic. Engine oil temp always runs the hottest on mine once she's up to temp.

Ya yesterday was 116. Im in AZ so it's hot

 

[TheEnder]

A/C turning off could be as simple as the truck trying to put as low of a load as it possibly can on an overheating engine, being another system to protect itself from ******** the bed i guess. Coolant, i’m not so sure. Have you replaced the coolant yet?


Sent from iPhone XS Max

 

[Lifted2wd]

A/C turning off could be as simple as the truck trying to put as low of a load as it possibly can on an overheating engine, being another system to protect itself from ******** the bed i guess. Coolant, i’m not so sure. Have you replaced the coolant yet?


Sent from iPhone XS Max

Yes. About 2 months ago when I replaced the radiator

 

[Travelin Ram]

I’ve seen worn or corroded water pump impellers do that. Rarely.

 

[RedSRT4Me]

Yes. About 2 months ago when I replaced the radiator

Check to make sure the A/C fan is operating. If the A/C fan is failing it will cause the air to blow warm and idle temps increase.

 

[Lifted2wd]

Check to make sure the A/C fan is operating. If the A/C fan is failing it will cause the air to blow warm and idle temps increase.

Ill check that today

 

[Lifted2wd]

Thing that is ******* me off the most is that it's sporadic

 

[Livinalittle]

+1 on the thermostat. Start with the cheap stuff and work your way up.

 

[eddie046]

I'd try also doing a good cooling system clean and flush. Might be some corrosion and dirt impeding cooling.