Engine gets hot at idle

[Dannyboy1966]

Originally Posted by tucsonjwt

Is the water pump actually pumping coolant? Do you see evidence of a water leak (rusty water trail) at the weep hole on the bottom of the water pump?

If you need a fan clutch, I would stick with AC/Delco factory part. I have not had good luck with flex fans. From the symptoms you describe, it sounds more like a bad fan clutch to me. When the engine is overheating and you pop the hood to check the engine, do you see the fan moving?

If ll else fails, a rare but possible coolant passage obstruction in the engine block could be the cause. A power flush might help that. You would have a shop with a power flush machine do that, along with a cleaning agent.

Tucsonjwt, The water pump is doing it's thing, I've had the Rad, cap off, and see movement (Though not as much as i can remember looking at other vehicles), but movement none the less. No water leaking out the weep hole, that was the first thing I checked while I was laying on the ground replacing a fuel line to the pump. (hard for me to get up and down off the ground so killed two birds with one stone).
I've found the fan clutch is grabbing like it should, and the blades are pitched in the right direction. It's never overheated fully, but yes the fan is moving. I can shut the truck off and go into a station to pay for gas, and after i'm done, start the truck up, and you can hear the fan roar for a few seconds moving air, then it slowly levels out.
I back flushed the system last fall, when I had it all open replacing hoses, and the thermostat (now it wasn't opening when I replaced it, but works now), only thing I didn't get flushed was the radiator.
As I said on a previous post, I think the previous owner replaced the Rad. with a single core when he swapped the Diesel out and put in the 350. Maybe he damaged the original during the swap. I found this out when I went to the GM Heritage web site, and downloaded my trucks build information. It's suppose to have the HD radiator, and clutch fan in it. Thats a great site by the way.

[Blessed66]

A radiator may be in your future. I'm not sure how hot it's getting in your neck of the woods (It's 93 degrees F as I'm posting this, in Texas), but typically the hotter it gets, the more problems related to inefficient cooling you'll experience.

Without knowing much about the length of your ownership, driving habits, and several other factors - I would guess that if you're just now seeing this problem, and the temperature is pretty warm, you might be doing well to invest in a radiator. It's your money, so please don't take this as a definitive answer because it's tough to troubleshoot across states, but if you're suspecting the radiator, it would probably be a good place to start.

My logic might be faulty, but it's like this; your radiator is the heat exchanger of the engine. Hot coolant gets cooled by the incoming air and helps to maintain operating temperature (along with everything else in the cooling system). If it's weak, or subpar, the hotter it is outside - the less effective it becomes. It sounds like you already think the radiator is the culprit, and if everything else seems to be working fine then you've probably found your answer.

Again, it's easy for me to spend your money for you, so just know I've been wrong before. My wife reminds me all the time.

[Dannyboy1966]

Originally Posted by Blessed66

A radiator may be in your future. I'm not sure how hot it's getting in your neck of the woods (It's 93 degrees F as I'm posting this, in Texas), but typically the hotter it gets, the more problems related to inefficient cooling you'll experience.

Without knowing much about the length of your ownership, driving habits, and several other factors - I would guess that if you're just now seeing this problem, and the temperature is pretty warm, you might be doing well to invest in a radiator. It's your money, so please don't take this as a definitive answer because it's tough to troubleshoot across states, but if you're suspecting the radiator, it would probably be a good place to start.

My logic might be faulty, but it's like this; your radiator is the heat exchanger of the engine. Hot coolant gets cooled by the incoming air and helps to maintain operating temperature (along with everything else in the cooling system). If it's weak, or subpar, the hotter it is outside - the less effective it becomes. It sounds like you already think the radiator is the culprit, and if everything else seems to be working fine then you've probably found your answer.

Again, it's easy for me to spend your money for you, so just know I've been wrong before. My wife reminds me all the time.

Yeah Blessed 66, it's been in the mid 90's here too (Kansas City Kansas), and rain, My god it's been like a steam sauna since we broke into the 90's. Don't worry about hurting my feelings telling me I might need a new radiator, I already have come to accept the idea, thats what I'm gonna need. Just I'm a tight a$$, and don't like spending money. LOL
Thank god I don't have the little wife anymore to remind me how stupid I am sometimes.. LOL

[tucsonjwt]

If you have a stock 350 engine a 2 core radiator should be enough. The last time I checked you can get one online (or locally) for about $120-$140. I gave up on having radiators rebuilt because new ones are relatively inexpensive. Also, you might get $35-$45 for your old radiator core (you should separate the brass/copper parts from any steel framework prior to taking it to the scrap yard.)