Any Problem with Switching to a 180 Thermostat in a Dodge 5.9L V8? - JeepForum.com

 
LinkBack Thread Tools
post #1 of 6 Old 05-02-2012, 01:53 PM Thread Starter
DECJ
Registered User
2000 TJ Wrangler 
 
Join Date: Aug 2009
Location: La Sal
Posts: 121
Any Problem with Switching to a 180 Thermostat in a Dodge 5.9L V8?

I've got a swapped-in Dodge Magnum 5.9L V8 engine in my 2000 Jeep TJ and I am about to do the plenum plate upgrade to my factory intake manifold.

While I am doing this work, I plan to replace the thermostat. I could of course just go with the same 195 thermostat that the factory used for this engine, but I have previously heard that a lot of guys have gone with a 180 unit.

I would also like to go with a 180 thermostat, however, I want to make sure that I am not going to get into any unintended consequences from a performance perspective by doing this. For example, if the PCM is looking for the engine to come up to operating temperature, I don't want to get into any potential fuel mixture or advance curve issues with the PCM wrongly interpreting the lower engine operating temp as an indication that the engine hasn't fully warmed up yet.

So, if anyone with either a Dodge Magnum 5.2L or 5.9L has switched to a 180 thermostat, or is otherwise knowledgeable about the way the PCM looks at the engine operating temp (as a function of coolant temp), please let me know if you have had any adverse performance problems or whether this move wouldn't be recommended for some reason.

Thanks in advance,
Don


2000 TJ, Dodge Magnum 5.9L V8/46RE auto, NV-241OR Rock-Trac tcase, Full-Traction LA, SwayLOK, 35" MT/R Kevlars on forged Center Line wheels, ARB's/Superior Super axles, etc.
DECJ is offline  
Sponsored Links
Advertisement
 
post #2 of 6 Old 05-02-2012, 02:54 PM
LJameson
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: Central Oregon!
Posts: 3,830
The problem with going to a cooler thermostat is like you said, the PCM will possibly stay in open loop and not operate as efficiently, dumping more fuel into the engine then it should.

Chrysler designed the engine as a whole unit to run as efficiently as possible with a 195* thermostat. And really, all the thermostat will help with is the minimum operating temperature that the engine will run at. During hot days, it will run at whatever temp your cooling system is capable of keeping it at. IMHO, I'd just stick to the 195* thermostat.

1990 YJ-The wheeler
2015 JK- The DD
LJameson is offline  
post #3 of 6 Old 05-03-2012, 08:52 AM Thread Starter
DECJ
Registered User
2000 TJ Wrangler 
 
Join Date: Aug 2009
Location: La Sal
Posts: 121
Yep, you're absolutely right.

Also, here's a comprehensive write-up on the subject on Dodge Forum ... http://dodgeforum.com/forum/2nd-gen-...-and-cons.html

I also received a response from a Dodge service tech on another board I posted to who basically gave a shorter version of the same information that was in the Dodge Forum write-up.

So, since I don't have a tuner/programmer, I am definitely going to stay with a 195 thermostat as I don't need to get even worse fuel mileage.

2000 TJ, Dodge Magnum 5.9L V8/46RE auto, NV-241OR Rock-Trac tcase, Full-Traction LA, SwayLOK, 35" MT/R Kevlars on forged Center Line wheels, ARB's/Superior Super axles, etc.
DECJ is offline  
post #4 of 6 Old 05-03-2012, 09:11 AM
comptiger5000
Registered User
1998 ZJ 
 
Join Date: Jan 2009
Location: Rochester, NY
Posts: 4,556
The PCM will still go into closed loop at 180*. It won't hurt anything to run a the 180* stat, other than maybe a small drop in fuel mileage. However, there's no good reason to do it, as the benefits are minimal. Heck, I'm one of the few running a 5.9 with power mods that still has a 195* t-stat in it.
comptiger5000 is offline  
post #5 of 6 Old 05-03-2012, 09:32 AM Thread Starter
DECJ
Registered User
2000 TJ Wrangler 
 
Join Date: Aug 2009
Location: La Sal
Posts: 121
Quote:
Originally Posted by comptiger5000 View Post
The PCM will still go into closed loop at 180*.
That's good to know as I wasn't sure what the closed loop temperature threshold was.

Quote:
It won't hurt anything to run a the 180* stat, other than maybe a small drop in fuel mileage. However, there's no good reason to do it, as the benefits are minimal. Heck, I'm one of the few running a 5.9 with power mods that still has a 195* t-stat in it.
I get bad enough fuel mileage as it is, so I don't want to add to that . By the way, here's a shot of my 5.9 going into my TJ. It also has a number of power mods as well ...


2000 TJ, Dodge Magnum 5.9L V8/46RE auto, NV-241OR Rock-Trac tcase, Full-Traction LA, SwayLOK, 35" MT/R Kevlars on forged Center Line wheels, ARB's/Superior Super axles, etc.
DECJ is offline  
post #6 of 6 Old 05-03-2012, 09:36 AM
comptiger5000
Registered User
1998 ZJ 
 
Join Date: Jan 2009
Location: Rochester, NY
Posts: 4,556
Very nice!
comptiger5000 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Switching from 33's to 35's do i need to regear mattwillard06 Tires & Wheels 9 10-16-2011 04:52 PM
Switching 5 1/4 to 6x9s my_304_cj7 Audio, CB & Ham Radios, GPS, & Electrical 2 02-25-2011 03:46 AM
Switching Radios - JK to TJ gabbatemarco Audio, CB & Ham Radios, GPS, & Electrical 1 05-27-2010 11:05 AM
Switching Speakers Over...... Cherokeekid88 Audio, CB & Ham Radios, GPS, & Electrical 3 10-26-2008 09:21 AM
Switching engines for a YJ hudelJP Engines & Drivetrain 0 03-21-2007 06:13 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome