Which thermostat should I get the 160* or the 180*? Are there any dowfalls to changing the thermostat to a 160 or 180?

 

If you live in a cold area then the 160 might give you some problems at startup and getting up to temp.

 

You should probably wait till you are more heavily modded to worry about the thermostat... it's really a fix for guys that have really changed alot of stuff and are having trouble keeping the temps down. If you lower the temp that the thermostat opens, you really aren't accomplishing much b/c it will take forever for the the computer to go into closed loop - and when you are in open loop, the truck is in 'safety mode' until it reaches operating temperature.

 

so are you saying that a person like myself would really not benifit from having a 180 stat?

 

Your mods are similar to those on my 2003 5.3 (FIPK, cat-back duals, HPP-3) and this is what I experienced before and after a t-stat change:

Before...typical WOT detonation from HPP-3 tune, not able to break tires loose from start without brake stall.

After...no detonation at all at WOT, now able to spin tires for several seconds from start with no brake stall.

I changed to a 160 degree t-stat last weekend. My temp gauge now sits right on 180 at operating temp. It takes about three minutes to fully warm up from a cold start. Temps in S. Fla have been in the mid-90s since I installed it. I believe that a noticeable difference will be realized in warmer climates with a cooler running engine. My engine is definitely making more power running at 180 degrees than at 210 degrees. I'm leaving today for a 1,500 mile round trip over the next week and will see if it has made any difference in fuel economy.

The only comment I have after making the change is that I would like to have the GM bean counter by the gonads who decided to save $1.50 by eliminating the radiator drain valve so I could make him feel about the same as I did when I had to remove the lower radiator hose and let two gallons of DEXCOOL pour all over me.

 

...or I could be wrong...

 

Update: Just returned from a trip from So. Fla. to over 5,000 ft altitude in the N.C. Blue Ridge Mountains. The daytime temp was around 70 degrees with the warmest day reaching 73 degress during the eight day trip. My engine temp gauge never dropped below 180 degrees. When pulling some of the steeper inclines, it would creep up to about 190 degrees. In the mornings with ambient temp about 60 degrees, the engine would still warm to operating temp (180) in just a few minutes. My trip fuel economy average was 18.9 mpg at between 75-80 mph. Best tank was 19.3 mpg.

 

The rad petcock is on the left side of the rad.
I run a hose off the drain
Instead of the core support filling up with coolant and dripping in 300 different places.

I also will be changing to a 160 and a 34 in rad - I will have Allen reshoot my PCM

 

The only thing on mine is a plug where the drian should be. My 03 was made last August, probably the week they quit putting petcocks on them for the 04 models.

 

The computer goes into closed loop pretty fast. Theres no difference between 160 and stock for going into closed loop.

I have a 160 and have verified this with EASE.

If you go with a cooler thermo, just get the 160. It runs at about 172 cruising, and gets a little hotter in stop and go traffic.