help overheating

[big j]

I have an 04 tahoe that is overheating.I have changed the radiator thermostat waterpump and oil but she still is running hot.Dose some one have a sujestion

 

[Slammed]

Clogged port in engine? Clogged heater core?

 

[amtronic1]

Any bubbles in the rad when warm?

 

[big j]

heater works fine and no bubbels in rad when at op temp

 

[amtronic1]

Maybe partially collapsed lower radiator hose?

 

[samotahoe]

i would check the temp on the hoses to make sure that your overheating rather than the guage telling you that your overheating. and if that checks out, get a block test kit from napa thats only a couple bucks. test for hydrocarbons in the cooling system and if the fluid changes color then you have a head gasket issue

 

[lesterl]

Check in the NBS forum, they may have an issue on the 5.3l that isnt as prevalent in the 5.7l, you have checked the fan clutch, pump, thermostat, and pressure cap right?

 

[big j]

Have not checked the cluchfan or radiator cap.

 

[samotahoe]

how did you bleed the system after repairs? might just be air in the system

 

[Beeker702]

Seems more like a fan issue. When does it over heat? All the time? Sitting at idle? Or driving down the thru way or in stop and go traffic? If anything your cluster gauge could be wrong cause I know the clusters have been on recall cause of gauges inop or not reading right

 

[Tex99Tahoe]

All of my overheat issues over the years on various vehicles were fixed by replacing the fan clutch (5 clutches to date, and counting).

 

[gary350]

Change the cooling system thermostat.

 

[big j]

Ok so here's where Iam at.I have changed the fan,radiater,thermastat,waterpump,radiatercap,blocktest(tested out just fine),moteroil,and transoil.I have all so put in a bottel of water weter from red line and moter still sems to run hot.My tahoe use to run at 195 all day long but now my bullydog gt tuner reeds 203-207.I have used an IR temp reeder on the thermastat housing and it reed 145 ,top hose reeds 154 ,block reeds 203, and heads reed 217. heads are aluminum so I know that they will run hotter then the block.So am I realy overheating or am I just being crazey thinking that Iam.

 

[gary350]

I assume you know your engine has a cooling system thermostat, engine temperature sensor, air temperature sensor, fan clutch thermostat.

OK, so your engine runs at 203 instead of 195 degrees. It is 8 degrees off. Put your new 195 degree thermostat in a pan of water and slowly bring it to a boil on the kitchen stove. Get a good accurate quick read photographic thermometer to watch the temperature as it increases. When the thermostat opens see what the temperature really is.

Do you still have your old thermostat? Cut the center out of it and cut the hole out to 3/4" diameter so you have a flat washer with a 3/4" hole. Do an experiment replace your cooling system thermostat with the flat washer then check the temperature. With cooling all the time the engine temperature should run cold about 140 to 150 all the time.

 

[Beeker702]

I wouldn't call that over heating. what state do you live in? now if it got up to 215-220 I would worry about it. these newer motors can handle the higher temps unlike the older motors

 

[lesterl]

What mix of coolant are you running? What state do you live in? Sounds like the coolant in the radiator is cool enough and that the thermostat is keeping the engine at the temps you are reading. Try a 185* stat....... Get an OEM stat.....