Getting Hot

[motormayhem]

Over the last few days my truck has been running hot. It did this about a month ago and I changed the T-Stat and it fixed it (went from a 190 to a 180). After that it never went over 190. This week I have done about twice my normal driving and noticed it gets to 190 a lot easier and has been peaking at about 200 and will stay there for a while before it starts to cool. The temps outside have gone from mid 80's to mid 90's in the last week or so but should the temp fluctuate that much? The radiator fluid is rust brown color and about 3 months old. I flushed the system with hose and got the radiator repaired/cleaned completely in january. Then I filled it up with distilled water and antifreeze 50/50 mix. Keeps getting rusty though. Why is it running hot and whats up with all the rust? When I flushed it I ran the water till it was clear out the block on both sides.

 

[Westech]

could be fan clutch failing or the radiator starting to plug up.

 

[transman]

Hate to say it but it could indicate a failing head gasket. Allowing the t-stat to get air bound and not open properly. bring the motor up to temp and check for continuing air bubbles in the overflow tank . not good.

 

[motormayhem]

Hate to say it but it could indicate a failing head gasket. Allowing the t-stat to get air bound and not open properly. bring the motor up to temp and check for continuing air bubbles in the overflow tank . not good.

There is no water in the oil, the coolant level stays the same, and it doesn't smoke out one pipe only. I will watch for bubbles when I get it all put back together (doing a flush and water pump). The fan clutch is pretty solid when the truck is cold and a little less solid when hot, but I can still only throw it maybe 1/4 a turn when it is hot.

 

[Barrman]

This is going to sound backward, but going down to a 180 thermostat might have hurt you. the 190 kept the coolant in the engine longer. That allowed the radiator to transfer the heat out of the coolant in the radiator. Now, the coolant is just flowing faster through the radiator because the thermostat is open more.

Make sense?

My 715 has a 396 big block in it. I had heating issues during parades and low speed trails because I dont' have a fan shroud on it. I went from a 180 down to a 165. 220 was hit if I slowed down for lights and such. I put in a 185 and it never sees over 185 now unless I am doing long slow mountain climbs. Just something to think about.

 

[motormayhem]

Anyone know if gmb waterpumps are good. I have the radiator out as it was leaking just a little and I am getting it fixed under warranty. I am going to do a new water pump and when I bought the truck it had a gmb waterpump sitting in the back sealed in it's box. Is this a decent pump? I know there is a bad pump out there that doesn't move water well and don't want to add to the problem.