02' Silverado 5.3L, overheating while idling

[Gito]

2002 Chevy Silverado 5.3L with 363k miles.

Drove out to Vegas from LA in 106 deg temp without any problems. No temp gauge movement outside of normal operating temp thru the entire trip.

Arrived to Vegas and while we checked in at the hotel we left the truck idling for 10 minutes (with the AC on). Our Silverado's temp gauge moved up to significantly but did not reach the red zone. It was about 102 degrees yesterday in Las Vegas.

Items that have been replaced;
Water Pump
Thermostat
Hoses
Coolant
Reservoir tank cap
Fan Clutch

I drove from the hotel check in to the hotel parking lot and noticed the Temp Gauge go down to normal operating temp right away.

Is this normal?

 

[SatinSilver]

Doesn't sound like it. I'd replace the radiator cap also. Not that it would fix the issue but you never know.

 

[Chris142]

No it's not normal. Is the fan clutch actually working? Just cause its new does not mean its good. If it was made by Hayden its definatly a suspect. We stopped selling Hayden fan clutches,too many bad ones from Hayden.

Could also be a partially plugged radiator that's not allowing the bimetal spring to get sufficient heat.

 

[mk378]

Check when cold that the radiator is staying completely full. That means you're getting proper flow between the reservoir tank and the radiator. If the radiator won't stay full despite repeated purging of air, the most likely cause is the top seal in the radiator cap.

 

[Chris142]

Originally Posted by mk378
Check when cold that the radiator is staying completely full. That means you're getting proper flow between the reservoir tank and the radiator. If the radiator won't stay full despite repeated purging of air, the most likely cause is the top seal in the radiator cap.

Its a cross flow radiator.if its leaking he should see it

 

[Audios]

Possible sticking thermostat? I just dealt with this on an 04 BMW, at idle it would creep up but at 1200 rpm it came back down. Let it get hot again and make sure the fan clutch is locked, otherwise its possible that the rad is clogged, although my experiences with a clogged rad was overheating while moving and came back under control at idle. A clogged rad also wont allow a mechanical fan clutch to heat up as well, so it may seem like its not locking but thats only bc the temperature of the air through the radiator is much lower from the reduced flow. Threw me for a loop on an 87 MB 190 TD, rad was clogged and multiple shops told them head gasket.

 

[spasm3]

I would make sure the thermostat and the fan clutch are delco oem. More money but less problems. I went through the cooling system on my avalanche and bought OEM water pump, fan clutch and thermostat. Not delco professional, not delco advantage. Not hayden. etc.

 

[mrsilv04]

Just went through this with a 2000 Sierra with a 5.3. It only started to get hot when idling and the A/C on. As soon as I'd get in it and it start to drive it, the needle would drop.

The radiator needed to be thoroughly washed out. It was literally chock full of dirt, bug guts and carcasses, fluff from trees, sand, grit...everything.

Cheapest fix ever.

 

[Gito]

Can hear fan clutch while taking off from a Stop, then fan clutch sound slowly disappears as you drive. Used all AC Delco parts but don't remember if any of them were "Professional" or anything else. Radiator is the original one.

 

[Chris142]

Originally Posted by Gito
Can hear fan clutch while taking off from a Stop, then fan clutch sound slowly disappears as you drive. Used all AC Delco parts but don't remember if any of them were "Professional" or anything else. Radiator is the original one.

Original with 360something thousand miles! That's pretty much unheard of as they usually break a tank well before 150k. Its definatly restricted due to age and milage.

 

[MaximaGuy]

Clogged radiator or fans are not turning on. How to diagnose a clogged radiator.
Get a clean pan and remove the drain on the radiator - the flow should be real fast and then trickle down.
Uneven flow is a classic sign of clogged radiator - if its not clogged refill the coolant back and check other components.

 

[Rhymingmechanic]

I don't know if it's normal or not, but my 2001 did what you describe at less than a year old. I left the truck running with A/C on while I looked around a junkyard near Powell, Wyoming. It probably wasn't 100, but close.

When I got back into the truck, the gauge had moved way above normal. It hasn't done that since, but I also haven't let it idle in the heat like that, either.

One thing to consider--these trucks have overheat protection that will turn on limp mode when the computer thinks the coolant has gotten hot enough. Yours must not be getting that hot.

 

[Les_Ismore]

Like mrsilv04 said, start with a good foamy wash of the front outside of the radiator, maybe with a good degreaser, (maybe engine cleaner but beware the aluminum...) and a garden hose flush from the back of the radiator forward. No pressure washers please

If there are any radiator shops left near you they can clean the inside by pumping cleaner through just the radiator (not the engine), and actually tell you the flow before and after cleaning.

 

[mrsilv04]

Originally Posted by Rhymingmechanic
One thing to consider--these trucks have overheat protection that will turn on limp mode when the computer thinks the coolant has gotten hot enough. Yours must not be getting that hot.


I don't believe the GMT800 generation of trucks is anywhere near advanced enough to have limp mode. You're talking about a model of truck that was introduced 20 years ago.

 

[Nick1994]

Originally Posted by Chris142
Originally Posted by Gito
Can hear fan clutch while taking off from a Stop, then fan clutch sound slowly disappears as you drive. Used all AC Delco parts but don't remember if any of them were "Professional" or anything else. Radiator is the original one.

Original with 360something thousand miles! That's pretty much unheard of as they usually break a tank well before 150k. Its definatly restricted due to age and milage.

X1000

 

[maxdustington]

Originally Posted by spasm3
I would make sure the thermostat and the fan clutch are delco oem. More money but less problems. I went through the cooling system on my avalanche and bought OEM water pump, fan clutch and thermostat. Not delco professional, not delco advantage. Not hayden. etc.
Just throw money at it and replace EVERY cooling system component with OEM on a 16 year old truck. BITOGers love to spend other people's money rather than diagnosing, but will complain when shops do the same.

Originally Posted by Les_Ismore
Like mrsilv04 said, start with a good foamy wash of the front outside of the radiator, maybe with a good degreaser, (maybe engine cleaner but beware the aluminum...) and a garden hose flush from the back of the radiator forward. No pressure washers please

When was the last time you cleaned a radiator?
1. There's no room behind the radiator for fit a hose nozzle/gun on modern cars.
2. Engine cleaner and degreaser? Why not just use coil cleaner that is intended exactly for this purpose.
3. If you try to rinse it with a hose, you will be rinising for probably 30 mins, this is how I can tell you have no idea what you are talking about. Just be careful with the pressure washer.

Some people on this board give really bad advice. Like the advice a dad who doesn't work on cars gives you when working on your car.

 

[Rhymingmechanic]

I think the feature must have been introduced 20 years ago, with the 1999 models.

Here's a page from the 2001 owner's manual:

 

[Les_Ismore]

My 2000 Chevy Silverado 2500 (not hd) DID have the limp/reduced power mode with increased coolant temps.
(currently at 265,000 miles of new england winters, second engine and trans and wait for it... original exhaust! Now retired to my fathers care)

Originally Posted by mrsilv04
Originally Posted by Rhymingmechanic
One thing to consider--these trucks have overheat protection that will turn on limp mode when the computer thinks the coolant has gotten hot enough. Yours must not be getting that hot.


I don't believe the GMT800 generation of trucks is anywhere near advanced enough to have limp mode. You're talking about a model of truck that was introduced 20 years ago.

 

[JLTD]

Originally Posted by Gito
2002 Chevy Silverado 5.3L with 363k miles.

Drove out to Vegas from LA in 106 deg temp without any problems. No temp gauge movement outside of normal operating temp thru the entire trip.

Arrived to Vegas and while we checked in at the hotel we left the truck idling for 10 minutes (with the AC on). Our Silverado's temp gauge moved up to significantly but did not reach the red zone. It was about 102 degrees yesterday in Las Vegas.

Items that have been replaced;
Water Pump
Thermostat
Hoses
Coolant
Reservoir tank cap
Fan Clutch

I drove from the hotel check in to the hotel parking lot and noticed the Temp Gauge go down to normal operating temp right away.

Is this normal?


Thread title says overheated, your description says the temp gauge "moved up to significantly".

Did it overheat or just increase the temperature?

I'm thinking it's normal. An increase in system temperature, while idling and not moving (lowest flow from water pump and low flow through radiator), in high temperatures (less cooling), with AC on (heavy heat load) will make it climb and stabilize at a higher level. Once you moved and gave it some gas, the water pump started moving more water and you got more flow through the radiator, which brought it to a lower level.

 

[Les_Ismore]

Originally Posted by maxdustington
Originally Posted by spasm3
I would make sure the thermostat and the fan clutch are delco oem. More money but less problems. I went through the cooling system on my avalanche and bought OEM water pump, fan clutch and thermostat. Not delco professional, not delco advantage. Not hayden. etc.
Just throw money at it and replace EVERY cooling system component with OEM on a 16 year old truck. BITOGers love to spend other people's money rather than diagnosing, but will complain when shops do the same.

Originally Posted by Les_Ismore
Like mrsilv04 said, start with a good foamy wash of the front outside of the radiator, maybe with a good degreaser, (maybe engine cleaner but beware the aluminum...) and a garden hose flush from the back of the radiator forward. No pressure washers please

When was the last time you cleaned a radiator?
1. There's no room behind the radiator for fit a hose nozzle/gun on modern cars.
2. Engine cleaner and degreaser? Why not just use coil cleaner that is intended exactly for this purpose.
3. If you try to rinse it with a hose, you will be rinising for probably 30 mins, this is how I can tell you have no idea what you are talking about. Just be careful with the pressure washer.

Some people on this board give really bad advice. Like the advice a dad who doesn't work on cars gives you when working on your car.

Hey, I owned this truck! And did exactly this when my truck had exactly this problem. Are you speaking from direct experience?
1) Pull off the upper radiator surround (8 bolts with 10 mm heads) plenty of room now smart guy.
2) Sure, but if you dont have coil cleaner, use what you already have.
3) An unskilled pressure washer user can destroy a radiator, a garden hose never will. Soak, wait, flush for 5 minutes- its a 30 minute job including dis/assembly.

Personal attacks really aren't necessary or helpful or welcome