Thermostat question

N

nycstev

Full Access Member
Joined
Feb 24, 2007
Messages
5,037
Reaction score
0
Location
ZOO YoRk CiTy
Changed this T-stat other day(172 F) . Truck still runs @ 200-205. Bled system once
will try again BUT...... DO YOU NEED TO CHANGE THE PCM ON REGULAR CAB FOR tHIS TO LOWR TEMP? Even so temp was still 200 on highway where fan wouldn' t really make a difference???? ANy ideas?

Steve
 
There has been many discussions on this. I have always felt that if your in summer time weather your truck is gonna run 190+ so I don't see where it helps. In the winter when it's cold outside may be different??:dontknow:

I have the 170 in mine and run 195-210 all the time!!
 
today it was 103 and i was idleing in traffic at about 190-195... i have the stageII
and you could hear the fan... the stock pcm won't cut the fan on eariler to it will
run a little more hot in the summer than a stageII

Sharpi
 
nycstev said:
how bout on the highway? Fan is out of the equation.. what you guys get?
Click to expand...
I live in southeast Texas on the coast. I have the Stage II PCM and thermostat. When the air temp. is above 75^ I typically run about 200 on the highway. I bought the setup in February and was concerned as Spring came along that I'd have overheating problems mid-summer. I haven't.

oldguy
 
Both my R/C and Q/C will not go over 185 no matter how hot its .... even sitting in Los Angeles rush hour traffic.
 
Put a 170 in mine and she still runs 200'ish.Dont worry about it.I thought I did something wrong.Bled the system just like you did.Did'nt matter.I have heard that dc and exteme eng.(B&G) are a little different as far as turning the fan on.have also thought about doing an aux fan setup but may not waste the time and $$.
 
To answer your initial question...the answer is yes. But you don't have to.

You are running right where most of us run temperature wise (unless you have your emergency brake on, still).

Some get worried about the temp of this engine...heat does cause problems, but not at the 200+ degrees you indicate. Remember this is a closed pressurized system. Trouble starts way above the boiling point...like 260+...

You are where you want to be.

Roy
 
I sit at 200 allday. Even the other day when it was 116 degrees, still sat at 200 even! Bled system 2x.
 
Marc T said:
There has been many discussions on this. I have always felt that if your in summer time weather your truck is gonna run 190+ so I don't see where it helps. In the winter when it's cold outside may be different??:dontknow:

I have the 170 in mine and run 195-210 all the time!!
Click to expand...

:dito:
 
Ok I read all you posts. Big thanks to all!
Here's the 60K Question.

WHY DID I PUT A 172 F StAT IN IF ITS STIll Gonna rUn @ 200
LMFAO!:rock: :rock: :rock:
 
My guess is that if you were cruising at highway speeds long enough, your coolant temps would have eventually fallen back toward 172 degrees. it takes a while in hot weather. Temps with a stock PCM will often creep higher than 200 degrees at low vehicle speeds because the fan is not set go to full speed until you are well above that mark. You just aren't getting enough airflow through your radiator to get down near your t-stat opening temp, even in winter.

As WGO alluded, not all Stage II flashes are the same in the fan department. My Boomer flash has the fans come on at about 185 but not reach full speed until 200 degrees, where my coolant temps top out. I run a 180 degree t-stat and bottom out there. The DC flash apparently has the fans come on full by 185 degrees. This keeps coolant temps lower but works the stock hydrostatic, power steering pump driven system a lot harder. And you get more fan noise. It also can make it more difficult during normal driving to get your oil temperature up toward 200 degrees, where it really should be for condensation burn off and best performance. Of course a few full trottle runs up to redline will solve this issue.

I honestly think that if you want to keep coolant temps lower the best approach is to install an electric fan setup. Why we don't have one from the factory is a bit of a mystery. However, lower coolant temps are not all that they are cracked up to be. 200 degrees is quite normal, and even has its benefits. What you really want to do is lower intake air temperature, which dropping coolant temps only does indirectly. Some guys go to methanol injection, especially with FI setups. I think a composite intake (with less heat sink) from the factory or the aftermarket would help a lot.

I can understand your frustration with the thermostat. Especially as it's a &%$#@!! to install...

Just my $.02.
 
Last edited:
Good Marketing Steve!

It is what makes our economy strong!

And we do appreciate your contribution to our way of life.
 
nycstev said:
Ok I read all you posts. Big thanks to all!
Here's the 60K Question.

WHY DID I PUT A 172 F StAT IN IF ITS STIll Gonna rUn @ 200
LMFAO!:rock: :rock: :rock:
Click to expand...

Before the NOS kit I had a DC flash 2 and the 172 T stat , the truck never ran above 200. Here in Houston the temps can reach well over 100 and in traffic in the 110s. When I installed the nos kit I reinstalled the factory pcm but kept the 172 tstat, the truck runs like it ran when I first bought it without any of the above mods. The temps are over 200 deg.s
 
hunter_angler said:
My guess is that if you were cruising at highway speeds long enough, your coolant temps would have eventually fallen back toward 172 degrees. it takes a while in hot weather. Temps with a stock PCM will often creep higher than 200 degrees at low vehicle speeds because the fan is not set go to full speed until you are well above that mark. You just aren't getting enough airflow through your radiator to get down near your t-stat opening temp, even in winter.

As WGO alluded, not all Stage II flashes are the same in the fan department. My Boomer flash has the fans come on at about 185 but not reach full speed until 200 degrees. I run a 180 dgree t-sat and my coolant temps bottom out there. The DC flash apparently has the fans come on full by 185 degrees. This keeps coolant temps lower but works the stock hydrostatic, power steering pump driven system a lot harder. And you get more fan noise. It also can make it more difficult to get your oil temperature up toward 200 degrees, where it really should be for condensation burn off and best performance. Of course a few full trottle runs up to redline will solve this issue.

I honestly think that if you want to keep coolant temps lower the best approach is to install an electric fan setup. Why we don't have one from the factory is a bit of a mystery. However, lower coolant temps are not all that they are cracked up to be. 200 degrees is quite normal, and even has its benefits. What you really want to do is lower intake air temperature, which lowering coolant temps only does indirectly. Some guys go to methanol injection, especially with FI setups. I think a composite intake (with less heat sink) from the factory or the aftermarket would help a lot.

Just my $.02.
Click to expand...

tHANKS!
 
VNM PWRD said:
Both my R/C and Q/C will not go over 185 no matter how hot its .... even sitting in Los Angeles rush hour traffic.
Click to expand...
Jt Thats weird because Mine In stop and go traffic does 200 even:dontknow: However on the freeway 170 to 175:rock:
 
nycstev said:
Ok I read all you posts. Big thanks to all!
Here's the 60K Question.

WHY DID I PUT A 172 F StAT IN IF ITS STIll Gonna rUn @ 200
LMFAO!:rock: :rock: :rock:
Click to expand...

It does do it job On Mine atleast. with the stock t-stat I was always running 205-210 even on the freeway:dontknow:
 
I will add this. The 6 speed in the RC is a definite plus when at highway speeds. These motors seem to like Low rpms in regards to temps.

I can run along at 70 in 5th and watch the temp gauge drop slowly, but usually never below 195ish. If I put it in 6th it will drop rapidly down to 185ish!!
 
Yup, yup, yup.

6th gear while pretty docile, is wonderful for mpg and temperature.

It is just so psychologically difficult to engage.
 
You must log in or register to reply here.

Latest posts

Support Us

Become A Supporting Member Today!

Click Here For Details

Random Media

At the park
2013 08 25a1%20Dodge%20Viper[3]
Viper Filter
032
Back
Top