kirtondog23

Gang,

I ahve an LQ4 swapped into a 1990 truck with the original 1990 radiator

I had the radiator repaired for leaks about a year ago and cant see any leaks now.

I have taken my truck up the canyon a couple of times in the past week and when doing so noticed the temps rasing about 25-30 degrees above general city driving condidtions and about 40 to 50 degrees over highway driving conditions.

I burped the system last night (truck was level) thinking maybe I had an air in the system and some air burped out but I did not have to ad more than a quarter cup of coolant to the system. I ran the heater while I did that and the heater does blow hot air.

the fan ran for the entire time I was burping the system which was about 30 minutes and the engine never ran past the city driving (stop and go in hot weather) stage. My fan is the original belt driven clutch fan, Engine is a 2004.

Shouldn't the fan cycle on and off?

I did not pull the T stat and check that for proper operating.

what do you guys think? I have a hard time thinking that that little amount of air should let the engine cycle that high. I also am under the impression that the fan should turn on and off.

The radiator seemed to be heating evenly once the system had been running a while.

I can post a couple of pictures of the set up if that is helpful.

Thanks!

bczee

iTrader: (12)

Could be many reason why your temp is higher.. I would check your T-Stat.

it sound like you have burped air out, have you filled from the top radiator hose ? check to make sure your steam vent ports and lines are clear.

Yes. the fans should cycle on or off as commanded by the controller (standalone or PCM). what is the temp that your reading as High ?.. what are your low/high fans setting at in the PCM / Controller?

How is the air flow with the fans on. Do you feel air being pulled through the radiator ? are the hose ok. and not collapsed ?

I would hope your not having internal engine problems. head gasket ! or oiling issues. Check for gas, oil or water in your systems.

Pop N Wood

iTrader: (1)

Does the computer control a belt driven fan? Most engines I am familiar with there is a thermostatic clutch that sort of tightens up and loosens with engine temp. With that type the fan never stops spining altogether.

Maybe the LS truck motors with belt driven fans are different?

What is the temp gauge reading?

kirtondog23

I wish i could give you an accurate read. my temp sensor is set up on this "wand" an dbunch of adaptors put together so it is somewhat removed from the block. as a result the temp reads at 115 to 125 on the highway and 145 in the city after the highway. I am guessing I should add about 80 to 100 degrees to the number on the guage. with that said when I go up the canyon it read 170, which could be as high as 260-270 I fear. 30 minutes of idling while burping the system only took me to 140 but the fan seemed to run conistently.

the check engine light has never come on in relation to temp. Would it at some point?

I don't know what the PCM has been set as or if the PCM controls the cluch. I will check to see what the airflow feels like.

when I burped it I just ran it without the radiator cap on, should I pull the upper hose and fill that way? Not sure where the steam vents are.

I dont see any other fluids in the coolant. I do have some oil that leaks out of the valve cover but that is it. Oil looks ok also.

bczee

iTrader: (12)

Sorry, I just assume you were using E-Fans.. my bad..! Disregard anything about the e-fan and pcm settings.

One thing to remember, these engine are designed to be running around 200 to 240ish.. this would be in the normal range considering the T-Stat is most likely a 195 or 205deg. For the OEM F-Body engine, the pcm doesn turn on the High speed fans don't come on till 237(?)deg (ac would trigger the high speed tho).

I would really suggest you get a accurate Temp Gauge on this. Without this. We are going to have lot of problem 2nd guessing. maybe use a infra-red gauge would at lease help.

So.. no discoloration in the coolant or engine oil...?

gofastwclass

iTrader: (2)

Agreed. The PCM has a temp sensor in the driver's side head and there will be an open spot on the passenger's side same location. Any reading from anywhere else is not going to be the same or potentially wildly inaccurate, especially with several adapters to connect your sensor as you described. I would borrow a scan tool that reads live data and see what the PCM says the temp is.

Keep in mind these (pretty much all modern) engines are set to run a little hot compared to the small blocks of old. This means 200-ish degrees isn't bad, especially with a factory stat. You can get them cooler than 200 all the time but it is not likely with a factory stat.