jsp9r

I've had a 2004 Suburban 1500 4wd for 5 years or so...has about 200K miles on it at this point. Toward the end of last summer I started having reduced AC effectiveness when stopped at stoplights on very hot days and you could start to see the engine temps climb above their usual spot as well. I replaced the fan clutch and it resolved the problem. But it also made the truck sound like it had a turbine engine under the hood, and there was a dramatic reduction in power over all. It was so bad, in fact, that as fall came around and the outside temps dropped down I put the original "bad" fan clutch back on so the truck was more driveable again. This spring, I bought a second new fan clutch under the assumption that the first replacement unit I got was DOA and had failed in an 'always engaged' mode. The second one I bought from a different supplier and different brand just to cover my bases. This second new fan clutch has the same problem in that is seems like it is always engaged and the truck is not much fun to drive. What am I missing here? It was never like this before the first fan clutch replacement. As a worst case option Im thinking of converting to an electric fan setup but it seems like there should be a simple solution here.

Thanks for your wisdom!
Jeff

subfan597

If trial and error is wisdom, my recent experience may help. Recent high outdoor temps had my temp needle rising too, especially when idling. I Youtubed a few videos and found one where the guy removed the fan and clutch, layed the assembly on the table with the clutch facing upwards and soaked the bi-metal coil in PB Blaster for a couple hours. It is this coil that expands when hot air hits it and opens the valve in the clutch which allows a fluid to flow between moving parts, effectively engaging the clutch and increasing fan speed till it reaches a 1/1 speed ratio with the engine. The increased fan speed draws more air through the radiator to keep engine temp at that usual spot that you mention. This coil can get corroded and fail to open the valve properly. I did the same, and it appeared to help for about a half hour and the dang thing did it again. I had just replaced the thermostat, hoses and coolant so it wasn't that. Then it dawned on me that I could not recall ever back washing the radiator with a garden hose. I took out the plastic intake housing between the air filter and the engine (2 metal bands), and the upper fan shroud (2 screws and 4 plastic connections). I then thoroughly hosed the radiator from the engine side a few times. The water on the ground was plenty dirty so I did it again till the water puddle cleared. I put everything back together, took it for a long ride but this time the temp needle stayed put. I appears that the dirt on the radiator fins acted as an insulating blanket that kept the radiator heat from being dissipated by the air flowing through it. So it appears it was a combination of 3 things, higher than usual outdoor air temps, a corroded and sticky bi-metal coil, and a dirty radiator that couldn't remove heat efficiently. Knock on wood, so far, so good...and it didn't cost a dime. As a big believer in keeping it simple, try this out yourself with your original clutch. As to why you have problems with your new clutches, all I can think is that they are the wrong parts., but I really don't know for sure. And by the way, be sure to cover the exposed intake on your engine as well as the opening on your air filter housing before you spray...like I forgot to do. Like I said, wisdom follows trial and error.