Another overheating Thread

[KJHagg]

2012 Ram 1500 5.7 Hemi overheating.

I've done everything I can think of, and everything my mechanic can think of, but it's still overheating when idling at a drive thru or stop and go traffic. Even tried different fans on a whim

Gauge runs at 208F-219F when driving.
It ****** goes 221+ and rising when sitting for a few minutes.

Running with a 180F thermostat, new radiator, new water pump, fresh antifreeze. Radiator cap and hoses are OEM. No mods or tuning yet.

Any ideas?

 

[tron67j]

Blockage somewhere in system. Could be combination of things. If you aren't original owner prior one could have had a leak that they tried to fix with that sealant crap which is now stuck in places. If original radiator could have blocked tubes that won't flush out. Water pump could be not working right or incorrect part. Maybe ask mechanic about running a 170 degree thermostat to see if there is a difference, it just opens quicker and gives .more of a headstart to cooling. Don't run without a thermostat whatever you do, not like pre-conputer vehicles.

 

[hunterdan]

Is the auxiliary AC fan kicking on when it gets that hot?

 

[MRFREEZE57]

Does it still have the grill shutters?
My truck would go up to 220 deg with factory 203 deg stat, removed the shutters and it hangs around 203 deg, no more surges up to 220.

 

[62Blazer]

When it overheats at idle or when stopped, but cools off when driving, that usually points to the radiator fan. Sitting at idle requires the absolute least amount of work from the engine, and thus the least amount of heat. Thus you need the least amount of cooling. Any type of driving requires more work and thus more heat. The difference is sitting at idle the fan is required to pull air through the radiator. Where as driving the speed of the vehicle forces air through the radiator. If you are driving 70 mph down the freeway the fan makes a minimal difference in how much air flow is going through the radiator.

The only thing I would check is see if you are sitting still but raise the engine RPM up (say to 2,000 rpm) does it cool down any?

I am also not familiar with working on a system with active grille shutters. If your truck has that I would verify they are working. If they are staying closed all the time the fan, assuming it is working correctly, may not be able to pull enough air.

If you start the engine up and sit there it should be pretty obvious when the fan kicks on as it gets warm.

 

[KJHagg]

Is the auxiliary AC fan kicking on when it gets that hot?

Yes, it's even been replaced as well.

 

[KJHagg]

Does it still have the grill shutters?
My truck would go up to 220 deg with factory 203 deg stat, removed the shutters and it hangs around 203 deg, no more surges up to 220.

I didn't know it had any but it's all original. I'm checking this now.

 

[KJHagg]

When it overheats at idle or when stopped, but cools off when driving, that usually points to the radiator fan. Sitting at idle requires the absolute least amount of work from the engine, and thus the least amount of heat. Thus you need the least amount of cooling. Any type of driving requires more work and thus more heat. The difference is sitting at idle the fan is required to pull air through the radiator. Where as driving the speed of the vehicle forces air through the radiator. If you are driving 70 mph down the freeway the fan makes a minimal difference in how much air flow is going through the radiator.

The only thing I would check is see if you are sitting still but raise the engine RPM up (say to 2,000 rpm) does it cool down any?

I am also not familiar with working on a system with active grille shutters. If your truck has that I would verify they are working. If they are staying closed all the time the fan, assuming it is working correctly, may not be able to pull enough air.

If you start the engine up and sit there it should be pretty obvious when the fan kicks on as it gets warm.

Good question. Yes, sitting in park I can rev it to 1500-2000 and get it back to 219F. Let off the accelerator and it goes up again.

 

[KJHagg]

When it overheats at idle or when stopped, but cools off when driving, that usually points to the radiator fan. Sitting at idle requires the absolute least amount of work from the engine, and thus the least amount of heat. Thus you need the least amount of cooling. Any type of driving requires more work and thus more heat. The difference is sitting at idle the fan is required to pull air through the radiator. Where as driving the speed of the vehicle forces air through the radiator. If you are driving 70 mph down the freeway the fan makes a minimal difference in how much air flow is going through the radiator.

The only thing I would check is see if you are sitting still but raise the engine RPM up (say to 2,000 rpm) does it cool down any?

I am also not familiar with working on a system with active grille shutters. If your truck has that I would verify they are working. If they are staying closed all the time the fan, assuming it is working correctly, may not be able to pull enough air.

If you start the engine up and sit there it should be pretty obvious when the fan kicks on as it gets warm.

Good question. Yes, sitting in park I can rev it to 1500-2000 and get it back to 219F. Let off the accelerator and it goes up again

 

[KJHagg]

When it overheats at idle or when stopped, but cools off when driving, that usually points to the radiator fan. Sitting at idle requires the absolute least amount of work from the engine, and thus the least amount of heat. Thus you need the least amount of cooling. Any type of driving requires more work and thus more heat. The difference is sitting at idle the fan is required to pull air through the radiator. Where as driving the speed of the vehicle forces air through the radiator. If you are driving 70 mph down the freeway the fan makes a minimal difference in how much air flow is going through the radiator.

The only thing I would check is see if you are sitting still but raise the engine RPM up (say to 2,000 rpm) does it cool down any?

I am also not familiar with working on a system with active grille shutters. If your truck has that I would verify they are working. If they are staying closed all the time the fan, assuming it is working correctly, may not be able to pull enough air.

If you start the engine up and sit there it should be pretty obvious when the fan kicks on as it gets warm.

We did try different fans but that didn't make a difference. Maybe we didn't try the right one? A

 

[KJHagg]

Does it still have the grill shutters?
My truck would go up to 220 deg with factory 203 deg stat, removed the shutters and it hangs around 203 deg, no more surges up to 220.

No AGS on the truck. It doesn't appear to ever have had them.

 

[Jeepwalker]

Did you replace the thermostat with an aftermarket one? They're known to be of terrible quality nowadays. Some guys install them backwards too (common misstep). You might remove it alltogether and see what happens. That's the largest blockage in your truck's system. Fan or not, it shouldn't overheat just sitting there idling w/o a thermostat in. You don't want to run your truck long-term w/o a T-stat, but it would be great to test.

Other questions: Are there bubbles in the coolant as the engine runs? Can you smell combustion smells in the radiator? Were you noticing 'gurggling' happening under the dash when you'd start the truck and drive away in the morning after first start, in the past few weeks? (all head gasket probable issues).

 

[grizzstang]

When you say you tried a different fan are you talking about the mechanical fan?

To me if it is not pulling enough air at idle I would look at your fan clutch. It sounds like it is not locking to pull air through the rad. If it is oily or if you have lots of miles it may be bad. I don't like aftermarket fan clutches either, the OEM ones work the best but they are pricey.

Check this out.

Symptoms of a Bad Clutch Fan and How to Test if it Has Failed

Symptoms of a bad engine clutch fan and how to test if it has failed. Also, how to replace a clutch fan. What is an engine Fan Clutch? A fan clutch controls ...

www.youtube.com

 

[KJHagg]

Did you replace the thermostat with an aftermarket one? They're known to be of terrible quality nowadays. Some guys install them backwards too (common misstep). You might remove it alltogether and see what happens. That's the largest blockage in your truck's system. Fan or not, it shouldn't overheat just sitting there idling w/o a thermostat in. You don't want to run your truck long-term w/o a T-stat, but it would be great to test.

Other questions: Are there bubbles in the coolant as the engine runs? Can you smell combustion smells in the radiator? Were you noticing 'gurggling' happening under the dash when you'd start the truck and drive away in the morning after first start, in the past few weeks? (all head gasket probable issues).

Some interesting questions I haven't been asked before!
1. I've replaced the thermostat with 180F from O'Reilly's. Is there an aftermarket thermostat I should consider? I saw a video some time back where the Ram owner drilled 1/8" holes in a 180F thermostat. He said the holes didn't let enough water to pass to make a difference but made it easier to burp the system when filling with antifreeze. Haven't tried that yet either.
2. I don't think the thermostat is in backwards but I'm definitely going to make sure.
3. Good point. I'll try this test without the thermostat when I get time.
4. On start up, no bubbles. I haven't checked when it heats up.
5. No combustion smells or gurgling that I've noticed. No unusual noises from the motor at all.

 

[KJHagg]

When you say you tried a different fan are you talking about the mechanical fan?

To me if it is not pulling enough air at idle I would look at your fan clutch. It sounds like it is not locking to pull air through the rad. If it is oily or if you have lots of miles it may be bad. I don't like aftermarket fan clutches either, the OEM ones work the best but they are pricey.

Check this out.

Symptoms of a Bad Clutch Fan and How to Test if it Has Failed

Symptoms of a bad engine clutch fan and how to test if it has failed. Also, how to replace a clutch fan. What is an engine Fan Clutch? A fan clutch controls ...

www.youtube.com

We tried different fan clutches. One we tried stayed on pretty much the whole time. Pretty noisy. I reverted back to OEM fan clutch.

Checking out the link now ...

 

[KJHagg]

When you say you tried a different fan are you talking about the mechanical fan?

To me if it is not pulling enough air at idle I would look at your fan clutch. It sounds like it is not locking to pull air through the rad. If it is oily or if you have lots of miles it may be bad. I don't like aftermarket fan clutches either, the OEM ones work the best but they are pricey.

Check this out.

Symptoms of a Bad Clutch Fan and How to Test if it Has Failed

Symptoms of a bad engine clutch fan and how to test if it has failed. Also, how to replace a clutch fan. What is an engine Fan Clutch? A fan clutch controls ...

www.youtube.com

Watched the video. It sure acts like what he described. I'm going to revisit my clutch fan again and make sure it's okay but I'm pretty sure it's fine.

 

[KJHagg]

Excellent feedback here, thank you everyone. With your help, we're going to figure this out.

 

[hunterdan]

Does it still have the grill shutters?
My truck would go up to 220 deg with factory 203 deg stat, removed the shutters and it hangs around 203 deg, no more surges up to 220.

2012 and older weren't equipped with them, only 8 speed non-rebel trucks.

 

[hunterdan]

Excellent feedback here, thank you everyone. With your help, we're going to figure this out.

Make sure the AC condenser isn't blocked up with debris. The stock fan clutch requires heat to engage and lock the clutch up. The hotter it is, the less it slips. But, if there's not enough heat making it to the clutch assembly, it may not lock up enough to engage and pull more air. If the situation goes away on the highway, that tells me you're not moving enough air at idle, but pushing enough through at speed to satisfy cooking requirements. Pull the grille off, let it warm up or turn the AC on max so the clutch fan and ac fan should all engage. Put a piece of paper against the AC condenser and see if it sticks to it. It should stick pretty well to the condenser. If it doesn't and it falls off or is barely holding on you've got a blockage in the fins that's not allowing air to pass through. At which point you need to figure out if it's condenser or radiator. Now, if it passes that test, then you either have a faulty thermostat, air in the system, or a bad water pump. A 180 degree thermostat should be easily able to maintain 180-190 at idle.

 

[Richard Kim]

Cooling fan module. A Ram head tech that I trust advised me to change mine at 150K as they tend to fail around the 100K mark. I am running 195 - 205 coolant temp in the Texas heat. I know oil temp is independent of coolant temp but oil temp has been running cooler as well.