2001 tahoe getting warm please help

[sikchevy]

just joined the forums, I've combed through the search and can't find what I'm looking for. I recently purchased a 2001 Tahoe 5.3 for my birthday. got it for 1700 with 140,000 miles. got it running. previous owner tried to replace intake manifold gaskets and had a hard time. now my issue is it will randomly jump over 210 to the 3/4 mark. I immediately turn the heat on and it will make its way back down to operating temp. I changed the water pump, thermostat and surge tank cap. bled the system the best I know how. suggestions on that would be great. still having the same issue randomly. took it today to pick up my kids and it stayed pegged right below the 210 mark. then later I did an oil change and drove it around after and it did it again. I'm at a loss. if there is somewhere that covers this in the forum that I didn't find please let me know. otherwise any input would be great. all hoses get hot. water pump is flowing good. could there still be and air pocket in the system????

 

[sikchevy]

please!!! I can't figure this out. its really stressing me out

 

[Rocket Man]

Possible the radiator is partially clogged. Might have it flushed. Also check to see if the fan clutch is working. If the fan doesn't turn on at 210 it needs to be replaced.

 

[ScottyBoy]

Sounds like the fan clutch might be bad or going bad. Check the fan clutch and see if it's fully engaging at running temps. Also, like mentioned above the radiator can be partially clogged either internally or externally. Remove the front grill and the fan shroud and completely clean the radiator fins by flushing water through it with a hose. I would try that first before flushing the inside of the radiator, especially since you said you already changed the water pump. If you have not cleaned the fins already, then do this step. Even if it's not the cause of your issue, it will definitely help. If it overheats COMPLETELY randomly regardless of how long you have been driving or how long the engine has been running, then I would DEFINITELY check the fan clutch.

 

[iamdub]

They still had mechanical fans on the '01? Ugh.

Intermittently getting warm could be air in the system or intermittently slipping fan clutch. Also, make sure that it actually is getting warm and it's not just the temp sensor acting up.

 

[ScottyBoy]

They still had mechanical fans on the '01? Ugh.

Intermittently getting warm could be air in the system or intermittently slipping fan clutch. Also, make sure that it actually is getting warm and it's not just the temp sensor acting up.

Yep, Efans didn't come out until 05. So all 04 and older have the clutch fan.

 

[sikchevy]

what is the best method to check the fan clutch is working properly? I have read to roll up some newspaper and stick it in the fan and it should stop.

 

[iamdub]

what is the best method to check the fan clutch is working properly? I have read to roll up some newspaper and stick it in the fan and it should stop.

It's supposed to "slip" when cold and "bite" when warm and essentially lock up at or above 210 degrees. You should hear it howl if you rev the engine when it's running higher than normal temps.

When it's cold, you should be able to easily spin the fan. It'll have some drag to it and not totally free-spin, but it definitely shouldn't be stiff. At operating temp, it should have a noticeable increase in drag. Next time the gauge indicates it's running warm, shut it off, pop the hood and see if the fan free-spins. If so, the clutch is bad. If you can spare the cash, it'd be a great time to upgrade to an electric fan setup. This conversion can get involved and pricey depending on how clean and reliable you wanna make it.

 

[ScottyBoy]

what is the best method to check the fan clutch is working properly? I have read to roll up some newspaper and stick it in the fan and it should stop.

I thought that if it stops, then the clutch is bad. When the engine gets up to temp, the clutch should engage/grab and the fan should spin as the engine is running. If the clutch is bad, then it will slip and basically be "free spinning". I remember someone telling me that if you shut the engine off the fan should stop spinning in 1-2 rotations. If the fan spins a lot more than that when you kill the engine, then the clutch isn't engaging and it's definitely bad.

 

[sikchevy]

Let the car get up to operating temp. Sounded like the clutch engaged and disengaged the whole time until it reached just below 210 on the dash then stayed constant. But didn’t sound any different or appear to spin any quicker. When I shut it off the fan stops immediately. Spinning it as hard as I Can I get maybe 2 fan blades worth of movement

 

[ScottyBoy]

Let the car get up to operating temp. Sounded like the clutch engaged and disengaged the whole time until it reached just below 210 on the dash then stayed constant. But didn’t sound any different or appear to spin any quicker. When I shut it off the fan stops immediately. Spinning it as hard as I Can I get maybe 2 fan blades worth of movement

Ok, so it appears that the fan clutch is ok. Or at least it is right now. Keep checking it a lot, ESPECIALLY when it starts to overheat. I had an old Cutlass with a fan clutch that was giving me hell trying to figure out why it was running hot. We finally saw that the fan clutch was only engaging sometimes. One day it would work fine, then one day it would not engage at all. So KEEP checking it.

 

[Rocket Man]

I'd check it next time it overheats, see if it's still spinning fast or if looks like it's changing speed or slipping.

 

[sikchevy]

Ok, the fan is really load and pushing a lot of air at cold start up. It seems to stay engaged for a while after startup. But when the car is getting over 210 and I rev the engine I can’t hear the fan. So I’m thinking that it might be having some issues. I have a 2002 avalanche and I’m going to just swap the fans and see if that fixes the problem before I throw more money at it. Thanks for all the info. I’ll post back after I figure it out

 

[iamdub]

Ok, the fan is really load and pushing a lot of air at cold start up. It seems to stay engaged for a while after startup. But when the car is getting over 210 and I rev the engine I can’t hear the fan. So I’m thinking that it might be having some issues. I have a 2002 avalanche and I’m going to just swap the fans and see if that fixes the problem before I throw more money at it. Thanks for all the info. I’ll post back after I figure it out

Good idea for a quick test.

I will say that it's common for the fan clutch to be "engaged" at cold startup. If you rev and hold the engine around 3,000 RPM, you should hear the fan's roaring quickly fade as the clutch releases. Of course, if you're idling a red light and the temp gets to 215-220ish, you should hear the fan roar again when you accelerate.

 

[retiredsparky]

I would invest in a new sensor for the gauge-that is the sensor with a two wire connection. The sensor with 3 wires connects to the PCM. It is very possible that the sensor is failing-GM and other manufacturers buy sensors according to cost, not quality.
Larry