I have read the stickies about cooling on the LT1. Very informative I might ad. Question I have is my car runs hot when at speed and cools down when in town/stopped. Here it is at 70 mph today, the check gauges light is on because I assume it is running hot:



I pull off the highway in town and not 5 minutes later the temp is here: Outside temps today are the hottest they have been in awhile, mid 90's



and you can see the add coolant idiot light is on. I checked the level, it seems fine. I have bled the system per the instructions. The fans are operating normally. I can hear them on high speed when it gets hot.

I read that body kits might need some sort of air dam in order to get proper cooling at speed. Anyone else have insight on this? Right now the car has AC delete and I am going to be re-installing the AC soon and I am afraid the added load will really cause an overheating condition. Anything else I can be checking?

 

your air dam is missing

it should run at just about the thermostat temp when at highway speeds

 

What does it look like? Nevermind...lmgtfy. lol

 

if your air dam is missing that could be the problem. it sounds more like the thermostat is stuck or clogged or radiator is plugged limiting the cooling capasity so at low stress it runs cool and high stress it gets hot. are you losing any coolant?

 

Not losing any coolant. Water pump is new, new radiator cap, thermostat replaced when I did the water pump. I'm not so sure about the stressed part, my highway ride is fairly flat and I'm just cruising along at 16-1700 rpm. I'm much harder on it in town...stoplight to stoplight racing...lol. Inside of the radiator (from the cap anyway) looks clean, no build up or anything unusual. I nave confirmed the air dam is gone. Looks like it used to be there, I was wondering what the broken pieces of plastic were bolted below the radiator. Looks like a trip to the pull a part is in order again. I'll probably go ahead and flush/refill and check to see if anything is blocking the air from getting to the radiator (like a critter nest). Thanks for the replies!

 

I'm with Craby. I'd think a clog somewhere. Is the coolant brownish at all? It should be cooler at higher speeds (due to more airflow) and hotter at low speeds/stops (until the fans kick on). Not the other way around.

 

Coolant is new, most of it anyway. no cloudiness our anything. I have been reading that missing the air dam will cause it to run hot at speed.

 

when i had my 3.4 it would run at about half way normally than i pulled into a steep parking lot and broke off the air dam that caused the car to rise to just under 3/4 in the same conditions

 

Also keep in mind at 1600-1700 rpm the coolant is moving slower than if youre driving in the city where the rpm is higher. Faster moving coolant is cooler because it circulates to the radiator quickly where it gives off most of its heat.

 

That is true. But the temp dropped back to normal while sitting still at a stop light. Never went that high again driving around town.