Twin turbo ls overheating issue

johnnunez29

Master Mechanic
May 9, 2022
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You definitively do not need a 160 degree thermostat. A 180-205 degree thermostat will work fine. Dropping your fan temps isn’t needed either. The idea with the fan temps is to have those settings be active only when the thermostat is open.

I’m concerned that you have air in the system. If you do, repeat if you do, then it will overheat until it’s out - and the thermostat and fan settings won’t be able to help an issue that’s created by air in the system.

Drilling holes in the thermostat will definitely help speed up the bleeding process. It doesn’t help cold weather operation, but I’ll guess your Florida address won’t care lol. Yup 109%. We don’t do cold down here. Maybe a couple “cool” days.
 

johnnunez29

Master Mechanic
May 9, 2022
282
64
28
From everything you've told us so far, you don't have a parts issue. It's a software, possibly temp sender, air flow, or coolant flow issue. In other words, I don't think spending money on it will fix your problem. The fix will probably be free, but need to find the true cause.
Do you have an infrared temp gun? Is the air coming off the fans hot? It should be VERY hot if you're overheating. No chance the thermostat is in upside down?
Tstat can only go one way in my application. Holley Midmount system. Has a t stat neck won’t fit backwards. Air Infront of radiator is cool but the air blown in engine bay is def HOT
 
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Streetbu

Know it all, that doesn't
Supporting Member
May 22, 2011
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So that tells me the coolant portion of the system is doing it's job. The engine is making too much heat. Something is definitely wrong because obviously an LS shouldn't overheat at an idle. New engine, never run before correct? New engines will run hotter than normal as they break in. How long have you had it running total? Maybe an hour or so
 
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johnnunez29

Master Mechanic
May 9, 2022
282
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So that tells me the coolant portion of the system is doing it's job. The engine is making too much heat. Something is definitely wrong because obviously an LS shouldn't overheat at an idle. New engine, never run before correct? New engines will run hotter than normal as they break in. How long have you had it running total? Maybe an hour or so
Probably about 1-2 hrs total. Engine was completely redone. Dipped, shot peen (o think it’s called) decked. Bore .30 over. Everything in it is new forged.
 

Streetbu

Know it all, that doesn't
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May 22, 2011
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With that much run time it should be broken in by now. How are you controlling the ignition and fuel? Fuel injection or carb and MSD box?
 

johnnunez29

Master Mechanic
May 9, 2022
282
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With that much run time it should be broken in by now. How are you controlling the ignition and fuel? Fuel injection or carb and MSD box?
Holley terminator x max. Pass side head does smoke quite a bit. Driver side doesn’t.
 

64nailhead

Goat Herder
Dec 1, 2014
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Upstate NY
Timing and AFR at idle?

Headers and down pipes wrapped?

Hood opened or closed!
 

Streetbu

Know it all, that doesn't
Supporting Member
May 22, 2011
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Central NY
The head is smoking? What does the exhaust smell like? Super rich?
 

johnnunez29

Master Mechanic
May 9, 2022
282
64
28
Timing and AFR at idle?

Headers and down pipes wrapped?

Hood opened or closed. Hood closed and only headers are coated with cerakote.
 

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