Engine running Too Hot?!

[Jeff Hines]

Hey everyone

I have a 2012 Silverado LT 4x4 with a 5.3.

The question I have is what should my Engine temp be running on this years motor. I noticed today while on the Interstate, it was hitting the mark after 210(I believe it’s the 230 or so mark) is this bad? Keep in mind it is 98’F today and my A/C is running. Just wondering if I may need to replace my thermostat or Flush my radiator and replace with fresh coolant? Will that help or have I got bigger problems? I attached a photo of my temp gauge.

Thanks for your time.

[Supreme Pizza]

Your gauge indicates that there is a temperature issue. Possible causes: 

 

   Internally clogged radiator

   Externally clogged radiator

   Faulty dash gauge 

   Faulty temperature sensor 

   Defective fan clutch / electric fan / electric fan temperature switch 

   Incorrect cooling fan rotation direction (clockwise / counter clockwise) 

   Low coolant 

   Low oil 

   VERY low or no oil pressure 

   Defective thermostat 

   Defective water pump 

   Plugged cooling system 

 

   Its unlikely that your fan is the issue, unless its rotating the wrong way. (fans are not needed at highway speeds) 

   

Assuming your water and oil levels are correct, I would start here to verify that you have an actual temperature problem: 

 

https://www.amazon.com/TOP-MAX-Thermometer-Temperature-Measurement-50-360°C/dp/B01N5FMX0G/ref=sr_1_1?ie=UTF8&qid=1527543736&sr=8-1&keywords=thermal+gun

  

[Black02Silverado]

Yeah, that is running hotter than normal.  Above post is good advice. 

 

If it did run that hot, then an oil change would be wise.

[Jeff Hines]

So I should be checking actual temp at the block, radiator or coolant hose?

[Supreme Pizza]

I would drive it in a way that produces the highest temperature reading on the gauge (Don't get it too hot, or you will cause immediate catastrophic engine damage), and then pull over quickly and shut it off. Then check temps with the infrared gun. Your thermostat housing is a great place to start. Try to check several different spots around the engine, hoses, radiator, etc. None of the parts should be much higher than about 210'ish. Anything near the exhaust manifolds will give a false reading. 

 

 

 

 

[Jeff Hines]

I will definitely try this. It really odd also cause, when I pull off the highway or interstate it will almost immediately start going down once I park. As in the gauge will start to immediately drop as if the fans start to cool it down. Then once I hit the road again back up? Would this still be one of the above issues?

[Supreme Pizza]

Normally, people overheat at lower speeds, not high speeds. Aside from a few obscure things, I listed all of the probable causes. If your vehicle overheats at highway speeds rather than city speeds, then I would expect that you have a cooling system efficiency problem. Normally you overheat due to low coolant. Next cause is insufficient air flow through the radiator. If have full coolant, and are overheating at highway speeds, then you have eliminated most of the normal issues. Efficiency problem means that you have a coolant flow blockage, or an air flow blockage. Maybe a problem with your water pump, thermostat, clogged radiator, piece of cardboard stick to your grill. Your cooling system is working too hard. Something is gumming up the works. 

[Jeff Hines]

Coolant is full. I actually pressure washed my radiator today to clean it out and it was still doing it.  I ordered that temp gun, think I might go and get a different thermostat tomorrow when the parts house opens up and also flush my radiator and put new coolant in as well. Driving around town and the city it stays right on 210 the whole time. Would the water pump be bad even if it’s not leaking? I know usually when they go out they start leaking out of the weep hole. That might be the next thing I look at if my first things don’t work out. 

[Supreme Pizza]

Coolant being full is a great place to start. Be careful pressure washing your radiator as you can fold the aluminum cooling fins over and cause an airflow reduction. The best way to check a radiator is with a light bulb. You can pull the rig into a dark garage, and put the light on the other side of the radiator. You will easily see clogs when the light is blocked. I have never seen a bad water pump cause overheating, aside from coolant loss - but its still theoretically possible. Your water pump is the "heart" of the coolant circulatory system. If you want to resolve the issue 100%, remove your thermostat. Removing It will drastically reduce your temperatures. The thermostat is mostly closed, most of the time - and basically slows the cooling system down. However, there is a reason that it is there, and removing it will negatively effect the fuel efficiency and long term wear characteristics of your engine. If you plan to sell the truck in the next 2 years, throw the thermostat out the window. If you are in combat zone, and your tank is overheating - throw the thermostat out the window. If you need your rig to run correctly RIGHT NOW - lose the thermostat. The thermostat is there to keep your engine "warm enough". It allows your engine to warm up much faster, and it also prevents your cooling system from "over cooling" your engine. Either way to slice and dice it, your thermostat causes your engine to run hotter, it assists cooling in no way at all. "new coolant" doesn't cool better than old coolant. Pee works just as well and iced tea as a coolant. Water is water. Yes, there are specialty coolants that are a little better, but essentially water is water.

 

Benefits of a thermostat: 

 

Better fuel efficiency 

Your heater will work faster on cold start up 

Your heater will be much hotter

Your engine will have better oil circulation 

Marginally Longer engine life

Your computer will be able to work better with expected temperatures 

 

 

 

Benefits of no thermostat thermostat: 

 

As long as you have coolant, you wont overheat. 

 

 

[Jeff Hines]

Wow I actually didn’t know a thermostat actually hindered a vehicle more then helped it. Well I’ll probably need to keep the thermostat in it, being I just bought the truck in February and don’t plan on doing anything with it fo quite a few years. So honestly after the temp gun checking, if it is actually running hot like it’s reading. What would honesty be the first thing you would do? If my truck will be fine for the next 5pr 6 years with our a thermostat then I’ll ditch it but if not then where would be the best place to start? Sorry for so many questions, I’m just really at a loss on this, it’s got me baffled. I use my truck to go to Nebraska a lot so I probably need my fuel economy unless it’s just a mile or so a gallon then screw it.

[Supreme Pizza]

Feel free to ask as many questions as you like. That's why we are here. If no one asks any more questions, this site will disappear very quickly. I'm not an admin though, I'm just a "nobody". Your thermostat is a very good thing in the long term, but only if everything is working perfectly. I bypass or remove all of the thermostats on my offroad vehicles, because you don't need the hassle of overheating when its life and death in the mountains. I keep them in place on my street vehicles as long as everything is working properly and i'm not having temperature issues - for comfort and convenience reasons. As for your issue, I would probably replace the thermostat with the lowest temp rating for that vehicle. Your rig will have a range for thermostats, like 180, 190, 195, 205. etc. Pick the lowest one. If that doesn't solve your issue, then maybe you need to bleed the system, or look at the OBD2 codes. 

[Jeff Hines]

I have a code reader and nothing shows up on it. The only code that has ever shown up was an oil pressure sending unit and I replaced that. I went and bought a temp gun and took some readings my gauge is currently sitting on 210 and the readings from the radiator to the thermostat to the inlet of the water pump all show below that. I will attach pictures. Like I said this is temp in town I will check on the highway tomorrow, but I wondering if my gauge or the temp sensor may be messed up?

[Supreme Pizza]

Keep in mind that if I look down and see a certain temperature on my gauge, I immediately click the ignition off and turn my turn signal on. I coast off the road, and I do not restart the engine until the temps have dropped. Overheating just one time can: 

 

Blow a head gasket

Crack a head 

Warp the block 

 

$1000-7000 repair. 

[CapitalTruck]

Bad thermostat or clogged radiator (internally) would be my guess

[Supreme Pizza]

Ya, probably one of those two. 

 

Are there any signs of radiator sealant? 

 

 

I worked on a vehicle TODAY that had stop leak in the radiator (bad sign).