02' Silverado 5.3L, overheating while idling

[WyrTwister]

Correct , on the highway , you most likely do not even need the radiator fan . You need it most , at idle , under the circumstances describes .

I have driven several 2000 + model Silverados & all were well behaved under those circumstances .

I would suspect the new fan clutch , but also check the belts & pulleys .

Worst case , consider an electric fan + thermostatic controller . But it should not need it .

Best of luck yo you ,

 

[samhainlimon]

Thanks for the feedback kind sirs. All of the suggestions are important for me to double check. I appreciate it. I am systematically checking things off.

Your going to laugh but I think the problem might actually be that there is air in the cooling system. Although my coolant reservoir says it should be full. I read the following and it was eye opening

"The surge tank must be large enough to allow the air to separate as the coolant flows through it. Air in the system will then migrate to the area just below the radiator cap, again so that it will be forced out first if system pressure exceeds the radiator cap's rating." - OK I know that
" The surge tank should be filled to a level just below the inlet ports, as shown in the system diagram above." - OK Yes I did that
" The continual de-aeration that a surge tank provides can be a huge benefit to your overall cooling system. We already discussed all the bad things that happen when steam or air are trapped in the cooling system. In addition to those, consider that 2% air in the system results in 8% less heat transfer, but 4% air results in a whopping 38% less!!" - Didn't realize it was to that extent -

I read about it here from another site


http://www.pirate4x4.com/tech/billavista/Cooling/#LSCoolingSystems

Granted they are talking about high performance mods but they still explain the LS motor cooling system in detail.

I remembered that it seems like I was only able to get about 10qt of coolant in rather than the required 16+ after most recently replacing the radiator. I figured at the time maybe there is water in the system somewhere (wouldn't water mixed with coolant be better for cooling? It's bad for corrosion and freeze protection but I heard good for cooling )

Sooo.. I put a little more coolant in it when it was cool and I ran it under the same conditions. It ran much cooler only to 217 this time. It seems to have also sucked the coolant in and I don't think I lost it anywhere.

P10crew maybe your on to something. You mentioned "Did you fill the coolant while the system was under vacuum?"

My answer: I think so lol. I used the Chiltons manual and You Tube instructions they all seemed similar, with the motor running so the coolant pump appropriately moves the fluid. Is there something else? Maybe that could explain why. All good suggestions I'll keep checking and keep you posted. In the meantime. I'm slowly adding small amounts of coolant. She ran cooler today in 94 deg weather so hopefully that's it.

 

[caprice_2nv]

Good to hear. These trucks are tanks. I'm hoping my 05 Silverado work supplied truck keeps on going, my boss thinks it should have died years ago so if anything breaks at this point he might just replace it with a newer one. I tried to talk him into sticking with the 99-2007 since we had such good luck with the 05 and 02. He sort of agreed at the time but he's not a car guy and I think he'll buy newer or give me his 2016 Silverado which I don't think will last as long.

 

[P10crew]

Filling coolant system while the system is under vacuum is common practice ( chime in here pro's) as it assures that there are no trapped air pockets in the heads coolant passages. You can also elevate the front of the truck to hopefully get the air pockets to rise to the radiator. I sure would have went along with who ever said that your new clutch was bad but..... maybe you found it.

 

[The_Eric]

Yes, cooling system vacs help a lot on some setups. Not always a guarantee, but it goes a heck of a long way towards ensuring that you don't have trouble

 

[clinebarger]

I vacuum fill every vehicle!! Though the GMT800 is not really bad about "airlocking" with the way the Surge/Degas Bottle is plumbed into the system.
Take a LSx 4th Gen F-body.....Those "airlock" like crazy!

*If you ever run across a LSx engine that you suspect is airlocked & you don't have a Vacuum Filler......Remove the upper radiator hose from the radiator tank & fill the engine through the hose, You have to hold the hose up in the air vertically.

 

[samhainlimon]

Thanks guys. I don't have a vacuum filler. I did refill coolant as you described clinebarger (plus I also filled the radiator similarly to try and avoid air in there as well. The place I suspect is the engine block. P10crew good thinking about raising the front end. I will try that. I have lots of hills around here so that was also part of my strategy as I drove around hoping to help purge any air in the system. Time will tell. On a side note. I did do the standard troubleshooting on the fan clutch. It actually seemed to be engaged most of the time which was why when I replaced it resulted in better mpg. I think it was engaging when it should not have been (highway speeds which was putting a slight drag on the engine. I noticed the slight mpg improvement right away. In any case I hear fan clutches can be difficult to test with certainty (unless they have obviously failed and you can stop them with a newspaper or something like that during idle. I hear they can fail intermittently. The new one definitely felt more "consistent when I manipulated by spinning it after I took the suspect one out and compared them. It was the original 15 yo fan clutch. I replaced it with AC Delco. If need be I'll try aniAC Delco on thermostat too . I think it's set to open up for 180 or 190. I'll keep you guys posted. It's interesting to see how many potential factors can be involved.

 

[WyrTwister]

Originally Posted by samhainlimon
Thanks for the feedback kind sirs. All of the suggestions are important for me to double check. I appreciate it. I am systematically checking things off.

Your going to laugh but I think the problem might actually be that there is air in the cooling system. Although my coolant reservoir says it should be full. I read the following and it was eye opening

"The surge tank must be large enough to allow the air to separate as the coolant flows through it. Air in the system will then migrate to the area just below the radiator cap, again so that it will be forced out first if system pressure exceeds the radiator cap's rating." - OK I know that
" The surge tank should be filled to a level just below the inlet ports, as shown in the system diagram above." - OK Yes I did that
" The continual de-aeration that a surge tank provides can be a huge benefit to your overall cooling system. We already discussed all the bad things that happen when steam or air are trapped in the cooling system. In addition to those, consider that 2% air in the system results in 8% less heat transfer, but 4% air results in a whopping 38% less!!" - Didn't realize it was to that extent -

I read about it here from another site


http://www.pirate4x4.com/tech/billavista/Cooling/#LSCoolingSystems

Granted they are talking about high performance mods but they still explain the LS motor cooling system in detail.

I remembered that it seems like I was only able to get about 10qt of coolant in rather than the required 16+ after most recently replacing the radiator. I figured at the time maybe there is water in the system somewhere (wouldn't water mixed with coolant be better for cooling? It's bad for corrosion and freeze protection but I heard good for cooling )

Sooo.. I put a little more coolant in it when it was cool and I ran it under the same conditions. It ran much cooler only to 217 this time. It seems to have also sucked the coolant in and I don't think I lost it anywhere.

P10crew maybe your on to something. You mentioned "Did you fill the coolant while the system was under vacuum?"

My answer: I think so lol. I used the Chiltons manual and You Tube instructions they all seemed similar, with the motor running so the coolant pump appropriately moves the fluid. Is there something else? Maybe that could explain why. All good suggestions I'll keep checking and keep you posted. In the meantime. I'm slowly adding small amounts of coolant. She ran cooler today in 94 deg weather so hopefully that's it.


Eric O. / South Main Auto has a video on his youtube channel showing the vacuum filling system to fill the system with coolant .

Basically vacuums as much air from the system as possible & then use the vacuum to pull the coolant into the system .

 

[samhainlimon]

Awesome! Thank you! I'll check it out