Posted: Apr 03 2011 at 5:59am | IP Logged

When idling for an extended amount of time(ie.long traffic delays),temp. starts rising.I flushed the system,replaced water pump,fan clutch,and thermostat.Still doing it.I did notice that the lower portion of the fan shroud is gone.Could that be the culprit.

Other than said conditions,seems very good while moving or at a traffic light-I drive it pretty much daily (small town/not alot of traffic delays).First noticed it when out of town and traffic was stopped at a tunnel-got off the last exit before entering the tunnel,got up to hiway speed and temp came down to normal.

Posted: Apr 03 2011 at 6:26am | IP Logged

Missing shroud piece could be the problem.  However, the radiator could be really blocked up.  Did you own this truck since it was new?  Did you buy it used?

I would certainly try to find the lower shroud piece at a "junk" yard.  If that does not solve the problem, I am going to go with a crudded up radiator.  If hard water was used,the coolant left in too long, etc during the life of the truck, no flush is going to remove the buildup of crud in the heat exchanger tubes.

Posted: Apr 06 2011 at 6:28am | IP Logged

Am4wag, now make sure that you use distilled water and change the coolant on a regular basis.  There will be crud in the block as well and it will move around more now that you have better flow.  I'd check the coolant every couple of weeks and if it starts looking dirty, I'd change it out.  You might even want to run a flush with an oxalic acid cleaner if there is a lot of rust showing up.  Works gret but make sure you follow the directions so that any excess is fully neutralized and flushed out.

Glad the solution worked!

Posted: Apr 06 2011 at 5:26pm | IP Logged

Left the truck at work yesterday/drove another vehicle home.Drove the truck back home today-first time on the road since replacing radiator;which is a mixture of 50-55mph.,and some small town lights/stops,and 25-40mph..On the 50-55 runs,I noticed the temp.guage needle holding around an 11:30-12:00 position,and a couple of times up to around a 1:00 position..Pretty much the opposite of what it was doing before replacing the radiator.

Now before I go any further,I want to make mention that now that it's warm,I'm not using the heater;and Boomer,I used Zerex 50/50 for Asian vehicles coolant.I'm just wondering if the radiator hose(s) could be collapsing (upper mostly) since there's more flow,as I really don't know just how firm they should be (?),and can't exactly observe them while driving.

Posted: Apr 06 2011 at 10:09pm | IP Logged

..

Worry more about the lower hose collaping. Some vehicles have a large spring in the lower hose to prevent collapsing.

Have a good one.. before they're all gone..Don S..

Posted: Apr 07 2011 at 6:20am | IP Logged

SO are you saying it now runs cool? (Pretty much the opposite of what it was doing before replacing the radiator).  Lakota is right,  Lowers often collapse, particularly as they get older.  The rubber gets flabby and as the water pump pulls, the suction collapses the hose.