Blackburb

Hey all, great forum here lots to read. Unfortunately my first post is not what I'd like it to be. I have a 2001 1500 4x4 Suburban 5.3 115k on the clock.

I bought the vehicle a week ago so I'm not very familiar with it, and also this is my first Chevy, I've always owned Toyotas. Anyways on to the problem: I've noticed that when I've driven the truck for more than 10 miles giving it ample time to fully warm up the A/C will become warm at idle, and the rear air is always lagging behind, and even warmer than the dash vents.

While idling yesterday (outside temps 117, Phoenix, Az) I was talking to a friend I had run into, and left my truck running in the sun. The A/C was on full blast and in the space of about 30 minutes the truck reached 235*. After seeing this I watched awhile longer, and it eventually made it to 240. At this point I revved the engine, cooled it off and went home. The truck ran great somewhere between 208-212 per my scan tool. When I arrived home, I let it idle again for about 20 minutes, sure enough up crept the temperature on both the scan tool and my dash gauge (ruling out a sensor issue).

Since I have no problems at cruising speeds, or even at slow speeds I assumed the fan clutch was to blame. I switched that out for a severe duty clutch and expected a change. No change, temperature has no limit idling with A/C on and will keep getting hotter up to and maybe beyond 240. So, I pulled the radiator, and since the truck is new to me, I went ahead and bought another, and a thermostat to go with it. Changed them out, same problem. Scangauge runs 208-212 around town, and when idling for more than 5-6mins temp creeps, air warms, and she heats up.

SO...Wondering if these fan clutches are just weak, I add some water wetter to my coolant mix, and have my mechanic-per his suggestion- install a 14" Hayden electric fan on the radiator to be used in tandem with the A/C when it is turned on. This reduced temperatures cruising around town in 115* pretty good overall running between 204-208*. Got home, tried to idle again for about 5-6 minutes, sure enough temperature hits 224 after 5-8 minutes, keeps going and I shut it down at 235* at this point with the electric fan going as well, the air had become hot and humid, if that indicates anything.

The water pump looks new, seems to function correctly, but could this be the cause of the problem? There's no oil in coolant or vice versa, no leaks, no smoke out of the exhaust. The truck doesn't do this when the A/C is off it will run aorund 215-220 and stay there! I refuse to believe this is normal for these engines to heat up like this at idle, even at 115* outside, or am I just putting too much load on the system in extreme temperatures?

I have no idea where to go from here, any ideas are much appreciated.

Joe In NY

Well, its a belt fan. They aren't near as good as electric fans like on newer suburbans. My 07 has two big fans they when on high, really move some air.

How is the idle? should be 600 rpm +

Clean your condenser and radiator. And do it properly. Dont take a pressure washer to it. That will make it worse. Try than and report back.

My 02 Burb never had over heat issues in the hot summer days of Texas 110 degree usual hot summer day. No, I don't believe this is normal because I did not have this problem.

73shark

Blackburb: Welcome to the forum.

The A/C warming at idle could also be due to a low charge but most likely due to insufficient air across the condenser.

Blackburb

I'm idling at about 550 with A/C on. It drops to 470 for a second when I cut the wheel right or left. I cleaned the condenser today, the truck is fully charged, had it checked yesterday. no luck. Looks like I might have to have a gm specific tech look at this. I'm at a loss for where to go next.

Thanks for the welcome.

Joe In NY

Hmmm. idle seems normal. Thats what my 07 idles at. And does the same drop for turning the wheel. You replaced the clutch so the fan is engaged...

Im at a loss right now...

Blackburb

Me too! Unless its something in the engine that's worn out and making the other parts work harder, but at 115k I highly doubt it. This thing has had mobile 1 since it was a baby. Could the timing be retarded? Maybe clean the throttle body and do plugs/wires? I'm no mechanic, would it be worthwhile to try this?

For the record, I ran her last night for 20+ minutes when picking my fiancé up for work, never saw over 213* gauge stayed perfect judt behind 210 and it stabilized somewhat averaging 212. Today in the sun, climbs again. Shut A/C off, temp drops runs great. The truck does have noisy lifters for 20-30 seconds until they prime every time I start it, even in this weather. Maybe the head is worn out? Again, at 115 and maintained, I doubt it but its my luck.

Joe In NY

No, its a cooling system issue. Maybe the water pump is wearing out? I would do Plugs, and clean the throttle body. Really helped with my idle at 120K on my 07. Used to idle 500 and dip down and then dive to 400 or worse when turning. Cleaned the throttle body and did the plugs. Much better idle, and gained .3 mpg! yay lol (just in time to go to FL and back!)

73shark

Maybe you have a thermostat that's starting to stick. Has it been replaced recently?

Blackburb

I did the thermostat along with the radiator and fan clutch. :/ the only thing I haven't replaced is the water pump which looks fairly new. When doing the fan clutch I saw chisel marks on the previous clutch leading me to assume the pump had been replaced, and old clutch put back on. I guess I'll go ahead and try the water pump as funds allow.

Joe In NY

Good luck. Maybe order one online? Rock Auto has a bosch pump for around $90. And those are pretty good. The ac delco ones are a bit more expensive.