Over heating

[wrench78]

So the last 2 days going into work i have had the engine top out at 240deg, light on, and engine too hot flash on my dash. Only last maybe 15-20 sec then drops down. The temp is all over the place. Noticed the needle is staying on the high end of the middle when it use to be under the middle line. Not towing or heavy loads currently. 2017 Laramie 5.7 hemi. Can anyone point me in the direction I should be looking? Pretty sure it's either the fan (mechanical), thermostat, or maybe the louver system? Any ideas?

 

[Burla]

Well toss a new thermo on it and delete that shutter garbage. Was the fan moving when it was hot? When fluctuates a lot could be air in system, did you check level?

 

[Atcer2018]

So the last 2 days going into work i have had the engine top out at 240deg, light on, and engine too hot flash on my dash. Only last maybe 15-20 sec then drops down. The temp is all over the place. Noticed the needle is staying on the high end of the middle when it use to be under the middle line. Not towing or heavy loads currently. 2017 Laramie 5.7 hemi. Can anyone point me in the direction I should be looking? Pretty sure it's either the fan (mechanical), thermostat, or maybe the louver system? Any ideas?

I’d say you are on the right track with thermostat and fan as starting points. I doubt it’s the “louvers” or AGS. Could also be a water pump or a radiator blockage. When was the last time you changed the coolant?

 

[wrench78]

Well toss a new thermo on it and delete that shutter garbage. Was the fan moving when it was hot? When fluctuates a lot could be air in system, did you check level?

Fan does spin with motor. Levels look good.

 

[wrench78]

I’d say you are on the right track with thermostat and fan as starting points. I doubt it’s the “louvers” or AGS. Could also be a water pump or a radiator blockage. When was the last time you changed the coolant?

Truck has 96k miles on it. I only have had it for about 9 months. Not sure when the last time anything was done on the cooling system.

 

[Burla]

I'd run some RMI 25 through it and any vehicle I bought with so many miles. Takes any impurities and traps them in over flow for extraction.

 

[wrench78]

I'd run some RMI 25 through it and any vehicle I bought with so many miles. Takes any impurities and traps them in over flow for extraction.

Thanks, I'll look into that. Never heard of it.

 

[Burla]

Thanks, I'll look into that. Never heard of it.

coolants don't have detergents, so when things go wrong you need to find the right flush. I swear by RMI 25 have used it mane times, I have not used any others that I remember so I cant comment. can get on amazon and eBay usually, or radiator shops. read up lots of other benefits as well, you do need to extract when goes into over flow tank

 

[jws123]

Also dont keep driving it til you fix it if it keeeps overheating like that your going to warp the heads and blow the gaskets.

 

[RamDiver]

AFAIC, after purchasing any vehicle with an unknown history, especially at a higher mileage, the usual SOP would be to replace all fluids.

And, at that mileage, If you change the coolant, may as well change the thermostat and EGR valve, at a minimum.

EGR valves used to cost only a few $ but not anymore. YouTube has videos on testing and cleaning EGR valves if you're so inclined.

.

 

[jayoz]

coolant level
visual inspections around hoses and radiator for leaks and sweet smell and shiny green or orange residue
presuure cab
coolant temp sensor
3way water pump
thermostat
coolant fan issues
main water pump
head gasket
good luck

 

[Atcer2018]

Truck has 96k miles on it. I only have had it for about 9 months. Not sure when the last time anything was done on the cooling system.

I’d start with a cooling system flush and the Burla recommendation of RMI25, it good stuff. After that thermostat, water pump, radiator.

 

[wrench78]

Ok, so found a new symptom. Got home from a 20min drive from work. Maxed out at 235 deg. Top hose warm. Radiator cap ice cold.

 

[Burla]

Replace t stat today or AM, it is stuck closed preventing coolant to rad.

 

[Burla]

dont drive on it, you don't know yet if you already effected performance on the times you over heated. Without coolant flow your engine can read 230f but it could be way hotter on other spots. Call in sick or late, and uber to a parts store if needed. It is an easy dyi job, the potential damage if you drive on it would not be easy dyi job.

If it is gummed up, you might want to buy a cheap t stat and do an RMI 25 flush and then in 500 miles toss it and put back OEM t stat. If the coolant looks good and the t stat in decent shape, then just replace with OEM t stat. just a thought on that, BTW good catch you could have saved yourself a ton of trouble.

 

[Bam930878]

Factory thermostat is 203 its a bit hot in my opinion i would switch to the 193 gen 3 temp tstat
its unlikely but (while engine is off) check your fan clutch should have some resistance and like many said a good flush of the system easy enough job to do

 

[wrench78]

So I have a leak. Not sure where. Doesn't look like up front. Here are some pics of the area I see coolant.

 

[Bigskyroadglide]

Check the weep hole on the water pump for antifreeze. Would be my first step, given the location of the leak

 

[wrench78]

Also. No signs of coolant in oil.

 

[Atcer2018]

Also. No signs of coolant in oil.

Stop driving it till you get the temperature spikes under control. You can warp a head or blow a head gasket driving the truck in an overheated condition even for short periods.

As another poster pointed out check the water pump for leaks. Driving at highway speed pushes fluids back under the vehicle so a coolant leak may not be readily apparent on the front of the engine.

Thermostat is the easiest thing to check. Start with a cold engine and let the truck idle. The temp will rise slowly at first from a cold start. When/if the thermostat opens you will see a quick reduction in temperature on the evic data. If the temp drops when the thermostat opens chances are it’s not the problem. Doesn’t guarantee it’s not the problem but is a good indicator.

Is the lower hose cold or warm after the engine is warmed up? The upper hose will be hotter than the lower but the lower hose should not be drastically cooler than the top hose. If the upper hose is hot and the lower hose cold it’s an indication the radiator is blocked or the water pump has/is failing. You can pull off the lower hose and run water through the radiator cap opening and see if it flows freely through the radiator to check for blockage. You can also remove the radiator cap while the engine is cold and allow it to idle till the thermostat opens. Look down the radiator cap opening for water movement. If no moment your water pump is suspect.

Not knowing the prior history of the vehicle it’s quite possible the previous owner used an incompatible antifreeze and the system is all clogged up. You really can’t tell the condition of the cool ant by just looking in the radiator. It’s best to drain the system and refill with distilled water to check the above recommendations. Being winter don’t leave the vehicle outside in freezing temps with only distilled water in the system. Give yourself enough time to diagnose the problem and get the proper coolant back in before leaving it out in the cold.