I'm talking about the 5.3 in my 2000 Silverado, not the bird. I put an aftermarket aluminum radiator in it and then ditched the clutch fan for a pair of ebay 14's. I am not happy with the cooling performance. It's starting to get hot outside and I saw 220 on the Torque app (the factory gauge is obviously a joke) in a parking lot today idling for like 5 minutes after a trip down the highway. So what is an ideal temperature for this thing to be at?

Does 220 seem about right?

And what is an oh **** temperature? It hit 232 briefly going back and forth up my hilly lawn while trying to park a trailer a couple of months ago. Trees and bushes will be trimmed before I play trailer slalom again, lol.

Anybody running LS1 fans on their truck? What kind of temps are you seeing? I bought a set a couple of weeks from a member here, just havent installed them yet. Hoping the shroud and likely better fans will help.

 

Which size radiator do you have? I have the bigger of the two in my Yukon and LS1 fans are not recommended because they dont cover the entire radiator properly. I bought a dorman set that matched the wider HD radiator. Second, fan temps and thermostat play a role as well. My all stock stuff would run 225-235 in traffic with the ac on during the summer. That appears normal for these engines and fans don't even come on until approx 220.

 

Personally I don't want my stuff running over 210* F under any conditions whether it's normal or not. I would prefer to see it running around the 190-195* area if possible.

This is especially true if the vehicle has an automatic transmission and uses the radiator for cooling fluid.

 

Not sure what size off hand, but thickness wise the new unit is about twice as thick as the old one. I know that the f-body shroud is a few inches narrower than the radiator, but they seem to be somewhat popular and it's got to be better than having no shroud at all I would think.

I have the fans set to come on at 195. You say the fans come on at 220..... where are you getting the temp reading from? Again, the factory gauges are disgustingly inaccurate, that's why I am asking.

235 seems pretty damn hot. I agree that 210 seems about right. I feel that my cooling is inadequate which is why I am asking about this, but maybe it's not. But it def is tranny cooler time, the factory unit is near worthless. Trans temp was about 210 the one time coolant temp saw the 230's.

 

I think the stock settings for the fans to come on is around 220 on LS1's. May seem hot but apparently its normal.

 

Yes, this is a stock tune setting for the fans.

 

with a stock thermostat and fan settings, the LS1 engines are in general around 220*~236* ish...
this was done from the factory for mostly emissions reasons

best power (as found by the Nascar guys in the LS series stuff) was around 210* "ish"

why people want to be in the 160*~180* range baffles me as you will lose some power at those engine temperatures with LS Engines....

 

I agree, even if you could get it to run 160-180, it probably would produce a slightly less efficient burn and hence less (or at least equal) power....plus low heat does not burn the condensation out of the oil as fast/well.

 

Well i have no interest in getting that low, I just dont know if I shold be oncerned when i see temps flash into the 230's. It sees awfully high to me, but I guess its normal.

 

Not sure how helpful RE topic as my LS engine is in a Cessna, but.... this created a number of engineering issues, and cooling was one that we did a lot of testing.

First off, drivers always say their engine temperature remains constant regardless of conditions. Fact is the automotive industry programs their gauges to read at the 12 o’clock position or same position if temps are within about 20 degrees.....this is left over from marketing efforts as owners believe there engine is better quality if it can maintain the temp exactly..... so don’t trust the gauge. OBD port indications will display correctly.

in an airplane, altitude, specifically the fast reduction in at atmospheric pressure with altitude, is a problem...... simple example is at 10k feet, it basically reduces your pressure cap by about 10 psi because you lose about 10psi ambient pressure. If we ran too low a pressure cap, the coolant would be quicker to boil over at a far less temp, so we run at cooler temps, about 180-190F, requiring a cooling system with more capacity to cool reserves (larger radiators, higher pressure cap pressure, ect). Anything below 180 decreases ability to vaporize moisture on shorter engine runs.

our ECM is a bit different, it has 2 ECMs for redundancy, but still controls a fan to regulate the 180-190F, but we typically reach 220F in climbs on hot days (full power, high nose up attitudes which decrease air volume into ducts, and slower speeds/air flow).... 220 is max temp for use because 50/50 coolant will boil over at far lower temps at altitude.

car engines are normally designed to run hotter than needed for reasons such as burning off more emissions and keeping the catalytic converter hot enough, so 200-210F is typical. With a standard 15 psi cap and 50/50 coolant, boil over is mid 250F ish at sea level and decreases with altitude fast.

i live in Colorado and see cars boiling over while driving up steep mountain roads during summer. Such conditions amplify cooling problems of a weak cooling system without extra capacity to handle not only the lower coolant boiling temp, but exasperated by the less dense air through radiator due to altitude and further thinned by high temperatures (density altitude). Speaking of density altitude, in hot air and/or lower air pressure conditions, at 100F your density altitude would be more than 2000 ft even though you are at sea level, meaning the air density is the same as that at 2000 ft on a standard day.....and you coolant system will only be as efficient as it would be at 2000 ft.

I suppose my point is, if you modify your cooling system to run hotter for better performance and reducing weight or for what ever reason, remember if you drive to higher altitudes or warmer areas, you may likely be coming close to boil over and over heat. Also, increased temperature may cause detonation with lower octane fuel. Whatever, be sure the system has sufficient capacity than needed at sea level to operate effectively at higher density altitudes.

hope this helps.

 

lower coolant temps are better for performance, up to a point. i've heard both arguments, but engine masters did an episode that showed that lower coolant temps are generally better in terms of power output. IIRC, the theory they endorsed was that it has to do with the difference in cylinder pressure vs plenum pressure that exists when the intake valve is open. we all tend to think that the piston is "sucking" air in, but the motion of the piston is just creating a low pressure area that wants to be filled with higher pressure air. there's still "stuff" inside the cylinder, no matter what. there will be no perfect vacuum to start out with. the hotter stuff is, the higher pressure there will be. so, hotter engine, less pressure differential between the gases in the cylinder and plenum volume, less cylinder fill.

now, slightly hotter temps are better for longevity and efficiency. engine wear does increase the colder the coolant temps are.

as a happy medium, i like the 190-200 degrees, i can achieve that on my ls1 with just fan settings. on a max effort street/strip car, maybe a little cooler, but not by much. maybe 180.

 

Put the clutch fan & shroud back on, Nothing beats it for CFM. Unless you get a 2005-2007 GMT800 fans/radiator set-up to fit.

 

what is your ignition timing at idle? Mine will run hotter with lower timing.....

does the ac work? If so, when is the last time you replaced the drier? If the drier is old and restrictive, believe this or not but it'll make the condensor hotter.

160 thermostat? nah. Why? obviously the engine will never run this cold except in the winter and you don't want a 160 stat in the winter. I never understood WHY people think an overheating car will run cooler with a lower temp thermostat. If it had a 180 in it and the cooling system was capable, it would run 180-185. obviously theres something wrong where a stat isn't going to fix it, unless the one he has isn't opening all the way.

 

Who are you asking?? This is an OLD thread!

 

damn. I don’t notice the date, but it came up in my “new posts” for some reason. I’m an idiot! lol

 

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. ..... 220? NOPE. Mine all run 198. HARD uphill pull in boost I see 210.