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Sierra overheating issue that's driving me nuts!

Nemesisdawn

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Nemesisdawn Enthusiast

Nemesisdawn

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On 12/2/2018 at 12:11 AM, SunShine01 said:

So you didn’t notice your vehicle being restricted by your brakes ?

Wonder if you’re not getting all your gears ? Are your RPM’s a bit higher than normal while going 60 or so ?


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At first I didn't, until I used the cruise control and the car constantly downshifted to get up to speed, and noticed that I can't go faster than 50mph.

 

All gears are fine, and the rpm sits on 2000ish while going 60.

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Z45 Senior Enthusiast

Z45

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Put the front bumper lower air dam back on.

 

Nemesisdawn Enthusiast

Nemesisdawn

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12 minutes ago, elcamino said:

Put the front bumper lower air dam back on.

 

The air dam removal will make the engine run hot on the highway? Don't most people remove these for ground clearance?

Z45 Senior Enthusiast

Z45

Posted
Posted

No, they remove them because of some other vane reason, looks.    The air dam is actually pretty important as to airflow through the radiator. It will have very little to do with engine temps around town but on the highway an engine can easily run hotter if the deflector is missing.  

Supreme Pizza Senior Enthusiast

Supreme Pizza

Posted
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Oil pressure doesn't necessarily mean that the oil system is working properly, but from the sounds of it - your oil system is probably OK. I agree with putting the air dam back on - even as just a test. 

redwngr Senior Enthusiast

redwngr

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Sure sounds like there are some plugged and/or dirty tubes inside the radiator.

Time to pull it and have it checked out at a rad shop.

Especially since this happened after 'flushing' the cooling system and changing the coolant type.

 

Belt tensioner is ok?

Belt routing has been double and triple checked?

diyer2 Senior Enthusiast

diyer2

Posted
Posted

The heat transfer or cooling off of the coolant/antifreeze is the job of the radiator. The rest of the cooling system is for fluid movement.

I still say replace the radiator.

 

:)

Nemesisdawn Enthusiast

Nemesisdawn

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3 hours ago, elcamino said:

No, they remove them because of some other vane reason, looks.    The air dam is actually pretty important as to airflow through the radiator. It will have very little to do with engine temps around town but on the highway an engine can easily run hotter if the deflector is missing.  

 

2 hours ago, starman8tdc said:

Oil pressure doesn't necessarily mean that the oil system is working properly, but from the sounds of it - your oil system is probably OK. I agree with putting the air dam back on - even as just a test. 

13 minutes ago, diyer2 said:

The heat transfer or cooling off of the coolant/antifreeze is the job of the radiator. The rest of the cooling system is for fluid movement.

I still say replace the radiator.

 

:)

 

56 minutes ago, redwngr said:

Sure sounds like there are some plugged and/or dirty tubes inside the radiator.

Time to pull it and have it checked out at a rad shop.

Especially since this happened after 'flushing' the cooling system and changing the coolant type.

 

Belt tensioner is ok?

Belt routing has been double and triple checked?

 

The air dam seems to be on. At this point the most likely scenario is either that the radiator was somehow f-ed up during the flushing or that there is still some air trapped in the engine block

 

Before I change the radiator, which is the only thing that hasn't been changed so far, how do I 100% make sure that there is no air in the engine? I'm currently running it with the cap off, but I've heard there's a certain hose that needs to be unplugged until coolant comes out of it. I don't mind spilling some coolant since I have a spare gallon.

Nemesisdawn Enthusiast

Nemesisdawn

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FWIW, when the tank cap is off and the engine is at op temp, I can see these small bubbles in the tank, and sometimes a bigger bubble comes out. But I've been running the truck for over half an hour and the bubbles don't ever actually go away.

 

 

 

Plus, no head gasket leak since I've tested it with a combustion gases tester.

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swathdiver Senior Enthusiast

swathdiver

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Green antifreeze is destructive to modern LS engines.  Mixing it with Dexcool is even worse, even if for a brief time.

Nemesisdawn Enthusiast

Nemesisdawn

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1 hour ago, swathdiver said:

Green antifreeze is destructive to modern LS engines.  Mixing it with Dexcool is even worse, even if for a brief time.

But before I changed the coolant type I thoroughly flushed the old coolant out with a water pumping machine at a shop. I'm pretty sure the coolant types did not mix. 

txab Senior Enthusiast

txab

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So before you started all of this, your vehicle didn't have this heating issue at all? You had the e-fan retrofit on this truck prior to this flush also with no issues?

Nemesisdawn Enthusiast

Nemesisdawn

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31 minutes ago, txab said:

So before you started all of this, your vehicle didn't have this heating issue at all? You had the e-fan retrofit on this truck prior to this flush also with no issues?

That's the thing that I'm not sure about. The truck is my brother's, and he told me that he swapped to e-fans because "the old radiator and fan weren't cooling enough". Presumably because the radiator was small and it's hot af here, but if what he's saying is true, then he did have overheating issues.

 

All my problems started after I flushed the rad and changed the brake booster (same day). I found out the brakes were clamping on much later, so I added spacers between the brake booster and the master cylinder so the brakes loosened up.

 

I don't know if the brakes are still partially clamping on, but they're no way near what they were before adding the spacers.

SunShine01 Enthusiast

SunShine01

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Posted

Why do I keep thinking the water is not circulating well enough as the engine is working ?

There should be enough air flow @ 60 to keep it cool enough. But if the coolant isn’t moving around freely from constriction or blockage it gets hot. Could be water pump, which was replaced, thermostat which was replaced, could the hoses be collapsing from air pockets possibly ? That would mean, there might be room for more coolant into the block while @ rest. Also, coolant diluted enough with water ?


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