Overheating

when air conditioner is on the fan should lock and might not be, scan for codes as yours is a semi electric hookup and may not be doing that. If only overheating with air conditioner on he may be right and it is not working. it may not be increasing speed when you rev the engine. also make sure you do not have things like bug screens in front of radiator/condenser as they cut 15% of air flow.

This guide can help as well

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please run down this guide and report back.

Thanks for the reply
So now as you told i need scan for error codes. if there is error i need to replace fan clutch?
There is no debris in front of condenser.
If fan clutch is bad it will it show in computer scan?

If the fan clutch is weak or bad, it will not increase the fan speed as under hood temperatures increase. Thus, it will overheat. Since everything else has been replaced, that would be what I suspect is bad. I have, however, seen situations where the lower radiator would collapse under certain conditions. Therefore, when the engine begins to get hot, check both the lower and upper hoses.

Is that 700 rpm's for radiator fan not enough after engine warm up to keep it cool with air conditioner on?

Thanks a lot for the response. i will give an update once it is done.

That actually sounds slow.

Hi i want to give an update..i checked my fan clutch it was not engaging

I kept a 10 amp fuse in pin 2 and 4 of relay no 45 in fuse box..the thing i noticed is the fan clutch is engaging when i am running like this and the temperature stayed in normal limits ..no more over heating

But once i remove the 10 amp fuse and connct back the relay no 45 ..the fan clutch is not enganging and again the problem of over heating
I swap the working fuse 45 and 46 ....the fuse is working
What may be the other possible cause for that
1. Relay is working

Check all connections to the relay to make sure there isn't a corrosion issue or a pin that has been pushed in and not making contact.

My engine overheats if I'm idling with the air conditioning or the vent is on... basically if the fan is blowing and I'm not moving my engine temp starts rising.

check to make sure your fan is turning properly and that the van shroud isnt cracked. sounds to me like insufficent convection due to those

Already replaced the thermostat, water pump, and fan clutch

go to a parts store they have a kit that checks the hydrocarbons in the coolant.u have poss. a cracked head or a bad head gasket.

thermostat? installed properly? i once got 3 bad ones in a row (just a bad batch) even brand new stuff can be defective

there could be other possibilities such as build-up inside the radiator (have professionally cleaned or replace, the auto parts store flushes usually won't touch the heavy internal build-up)...the radiator is supposed to efficiently transfer the heat from the water, to the outside air.

vane restrictions from mineral build-up will not let the water flow thru the radiator fast enough---this would be like pinching off the main hoses into the radiator. if this is the original radiator, this may very well be the problem if the other stuff checks out

i have seen this issue a lot in my region, with minerals in the water supply. if the entire system has not been flushed out, rusty water etc could prevent the radiator from doing it's job

a head/ head gasket issues can cause overheating....symptoms might be loss of coolant, running rough, water in the oil, oil in the water

good luck

keep us posted

the medic

I tried the engine sealant, and seemed to work for a couple of weeks before overheating again, then the brand new water pump I put in a month earlier went out , so I put another one in and it seemed ok for about a week before overheating again, should I try the engine sealant again?

I would be looking at getting the radiator core cleaned as you may have partial core tube blockage, this sealant is a waste of time and money, often they cause more problems and can compound others as well.

Engine Cooling problem
2004 Chevy Trailblazer 6 cyl Two Wheel Drive Automatic 130k miles

I have noticed that I have a smell coming from the engine and check under the hood. Found that it was coolent. My resv. tank was empty and add some but empty again. Could this be my water pump gone bad and starting to leak?

Fill the system and use a pressure tester, this will pinpont any leaks. Could be as simple as a hose, or cracked recovery tank, to a head gasket...

P0483 - Cooling Fan Rationality Check Malfunction . What needs to be repaired or checked ?

That code is "Cooling fan control circuit" problem. You need to test the inputs and outputs of the relay and the relay itself.

My 2004 chevy trailblazer EXT LT with a v8 just started making a whirring sound when I accelerate and all of a sudden just started over heating I changed the thermostat it seems to overheat faster if I turn the heat on it gets hot fast and the check gauges sign comes on I hear bubbling and liquid leaking wan I turn the car off..

have coolant system pressure checked for an internal leak like a head gasket. also when hot turn off engine and check radiator for cold spots if you feel any rad is bad.

ok thank you..i dont think it will make it to car shop tho

it sounds to me like you have a bad cooling fan.it screws in to the water pump shaft.it is a very ,very common issue on these trucks and both of your symptoms are indicative of a fan issue.

I have change the motor, the transmission, clutch fan(factory), water pump,raidator, thermostat And its still overheating! Someone please help. I have pretty much have a brand new car under the hood but my car is overheating i dont get it

What size engine do you have?

Have you check the temperature sensor?

Also, Chevrolet put out a bulletin to reprogram the PCM because of this.

This is the post.


Condition
Some customers may comment on higher than normal engine coolant temperature gauge
readings when operating the vehicle in very high outside ambient temperatures, and in
stop and go or slow moving traffic.
Cause
Reduced air flow across the radiator and preheated air from stopped or slow moving
driving conditions from traffic congestion may result in normally higher engine coolant
operating temperatures as indicated by the temperature gauge.
Correction
Technicians are to reprogram the PCM with an updated software calibration. This new
service calibration was released with JIS satellite data update version 73 available July 7,
200t As always, make sure your TECH 2(R) is updated with the latest software version
This new calibration win cause the PC?sÍ to command small amounts of additional fan
engagement to control engine coolant temperatures and gauge readings closer to a
customer perception of normal.


A Tech II scan tool will do this, if you cannot get access to one, a dealership will have this. Try this first and let me know.

Sean

Around how should that cost?

V6 4.2..the water in the radiator pretty much evaporates.

It shows to be warranty work. Hopefully it should be free. If not, it shouldn't be more then a hundred dollars for them to hook up the scan tool and reflash it.

Sean

If you are not seeing any radiator fluid leaking, then it has to be going through the engine and being burned. How much coolant are you losing, or how much are you having to add? If it starts to overheat, don't drive it. You don't want to have to replace the engine again. Did you change the engine out or have someone else do it?

Sean

Did you replace the engine yourself or have someone else do it?

Sean

Over the last year the temp gauge would climb(creep) to a temp that we hadn't seen before. (my wifes car). Since the car is just over 5 years old and I hadn't done a coolant flush, I had one done prior to vacation hoping that might solve the problem but it didn't, in fact it's a little worse. Prior to the coolant flush there was never evidence there was any coolant leakage. I blew out surface of the radiator , belts are new, etc.
The radiator fan moves freely but after watching operation it seems that the fan is a little slow to come on and after a short ride and a restart in warm weather is also slow to come on and if the A/C is on causes short cycling of the A/C compressor. (high head psi?) I understand the the fan blade is controlled by an electronic clutch system. Is this driven to engage on temp rise and also signaled to disingage? In any event has anyone had this problem

Hey Jdimond,

Try replacing the thermostat the coolant temperature sensor reads the temperature reports this data to the computer and in turn activate certain components.

Also here is a guide that goes over all overheating problem that will help you get to the bottom of the problem.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

I would start by checking for a blown headgasket also which would cause the problem you have described.


https://www.2carpros.com/articles/head-gasket-blown-test

Let me know how it goes.

Best, Ken

Hello, I have an 02 trailblazer and presents this problem: when I start the engine the fan clutch engages and it blows 100% (a little noisy), then when temperature rise up until 75°C, it desengages until the engine comes overheated (about 120°C) and engages again, but its too late to cool the engine. why is this happening? it´s the thermostat wrong? or the fan clutch?
Besides, I checked coolant level, looked for leakage and everything looks fine, I went to a mechanic and he said that the fan clutch was damage, but I dont believe him because it works, not when I need it, but it engages and disengages.
This occurs when I'm travelling or in hot days.

There is a TSB (technical service bulletin) concerning erratic and noisy fan clutches on Trailblazers and Envoys with the 4200 engine.

Talk to GM service about getting this replaced for free or at reduced cost.

I have an 02 TrailBlazer with 142,000 miles, that is running hot. First of all, I added some FiberLock to the radiator to stop a leak that was coming from the area near the a/c compressor. The engine was not overheating before I added the stopleak. Now it is running about 220+ while driving. Setting idle it stays around 190. I replaced the fan clutch and flushed the cooling system and filled it with fresh 50/50.. I am suspecting a clogged radiator due to the stopleak I added. My biggest fear is a blown headgasket. The vehicle runs and idles great. Oil on the dipstick looks good. I would appreciate your opinion. Thanks!

have the coolant system pressure checked for leaks, if it's internal it will show up by a pressure loss. after engine is warm shut it off and feel radiator for cold spots if any cold spots replace the radiator as it should be the same temp across

I have a 2002 chevy trailblazer I can drive it for a week and then it starts to overheat I have replace everything but the radiator what could be wrong with it.

Please explain "drive for a week" and replaced everything-what was replaced? as to starts to overheat- gauge moves up? boils over? Radiator OEM? ie. 13 yrs old

i replaced the fan clutch and thermostat and it still overheats. I do not want to spend another $200.00 when it could be something simple and i am spending all this money.

fill coolant system then go to auto parts and rent their pressure checker check for a bad head gasket or internal leak. then when warm/hot with fan disabled and engine off check radiator in a few spots if any cold spots are felt radiator is bad and needs replacing. there is also a chemical you can get at auto parts to check for head gasket. either is fine.