Reason I'm asking....with the clutch fan back on and a 180* t-stat my truck cruises between 200 and 210 and idles as high as 225*. My water pump has about 100k miles on it. I just picked up a new one today, but does anyone know what happens when one goes bad? Do the gradually lose the ability to efficiently pump water? Sucks, because I have a brand new 180* stat in there, and the new water pump is the 05+ style, so I have to buy ANOTHER thermostat.

 

Was your new engine running cooler before?

 

I had a 160* stat and e-fans on the old engine. Would run between 190 and 200 in hot weather and idle in the 190's.

 

I'm going to say thats about normal. with my 160 stat, mine cruises around 175-180. At idle in this heat will creep on up to 200-210.

 

I don't think it's normal. I have a 34" radiator in there. My mom's 2000 Suburban with the 27" radiator and clutch fan NEVER got past about 215*, either at idle or when towing up a hill at WOT 2nd gear at 60 mph/5500 RPM for 5 minutes straight. I understand my setup is a totally different animal, but it shouldn't get that hot when idling....

 

you might still have small air pocket...ive been fighting with mine a few days and finally think i have most of it out. i was seeing 225* at 40 mph cruise speed and 240 at one point now that i drained and started all over 190-205 and 197 idle.oh yeah thats with the 160*stat.with that new engine it might be normal...

 

I'm running the 34 inch radiator too, but with electric fans. Do you have the fan shroud installed?

 

Yes I do.

 

Do you have the little hole on the thermostat facing up? If the stat doesn't have a hole, I would drill a very small one and put it at the top when installing.

 

The only water pump failures I know of are the impeller spinning off the shaft=overheating immediately. Or, seal going bad and leaking coolant out of the weep hole in the bottom.