Dual thermostats - Diesel Place : Chevrolet and GMC Diesel Truck Forums
 
Home Forum Market Place Garage Lounge (2) Tuning Library DTC Tool Register Vendors
Go Back   Diesel Place : Chevrolet and GMC Diesel Truck Forums > GM Diesel Engines > Duramax Second Generation: 2004.5-2005 (LLY)
Register FAQ Forum Rules My Replies My Threads Mark Forums Read Auto EscrowAuto LoansInsurance

DieselPlace.com is the premier Duramax Diesel Forum on the internet. Registered Users do not see the above ads.
Closed Thread
 
LinkBack Thread Tools
Old 04-20-2004, 11:19 PM   #1 (permalink)
Hit Man X
Diesel Head
 
Join Date: Mar 2004
Location: Mansfield, Texas, USA
Posts: 34
iTrader Score: 0 reviews
Send a message via ICQ to Hit Man X Send a message via AIM to Hit Man X Send a message via MSN to Hit Man X Send a message via Yahoo to Hit Man X



I read that these truck have dual thermostats. Can someone explain how this works and why two?


Would there be any reason for a lower temp thermostat in HO applications?


Thanks!
__________________
Diesels are lazy, and they smoke.
Offline  
Quick reply to this message
Sponsored Links
Advertisement
 
Old 04-23-2004, 08:41 PM   #2 (permalink)
GMworldclassmaster
Diesel Technician
 
Join Date: Apr 2004
Location: Houston Texas
Posts: 139
iTrader Score: 0 reviews
Send a message via ICQ to GMworldclassmaster Send a message via Yahoo to GMworldclassmaster

Thermostats (6.6L Diesel Engine)


The thermostats are coolant flow control components. The purpose of the thermostats are to regulate the correct operating temperature of the engine. The thermostats utilizes a temperature sensitive wax-pellet element. The element connects to a valve through a piston. When the element is heated, it expands and exerts pressure against a rubber piston. This pressure forces the valve to open. As the element is cooled, it contracts. This contraction allows a spring to push the valve closed.


The 6.6L diesel engine requires two thermostats for correct coolant flow. The front thermostat is a dual purpose thermostat. The front thermostat controls the coolant flow to the bypass port and to the water outlet. The rear thermostat only controls the coolant flow to the water outlet.


When the coolant temperature is below the rated thermostat opening temperature, the front thermostat valve remains closed to the water outlet and is opened to the bypass port. The bottom portion of the thermostat is raised off of the bypass port while at the same time the top portion closes the coolant flow to the water outlet. The rear thermostat also is closed to the water outlet during engine warm-up. This prevents circulation of the coolant to the radiator and allows the engine to warm up quickly. After the coolant temperature reaches 82C (180F) the front thermostat primary valve opening temperature, the front thermostat primary valve will start to open. The coolant is then allowed to circulate through the thermostat to the radiator where the engine heat is dissipated to the atmosphere. As the engine coolant reaches 85C (185F) and more coolant demand is required the front thermostat secondary valve begins to close the bypass port and the rear thermostat begins to open coolant flow to the water outlet. The thermostats will continue to control the coolant flow by opening and closing. The front thermostat will be fully open when the coolant temperature reaches 95C (203F) the rear thermostat will be fully open when the coolant temperature reaches 100C (212F). The thermostat also provides a restriction in the cooling system, even after the it has opened. This restriction creates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block
__________________
GM World Class Master Tech   (Service and Body)
Shop Foreman
12 years GM experiance
Offline   Quick reply to this message
Old 04-24-2004, 11:28 PM   #3 (permalink)
SAYWHAT
Diesel Master
 
SAYWHAT's Avatar
 
Join Date: Feb 2004
Location: Tomah,WI
Posts: 1,079
iTrader Score: 0 reviews

Minnesota/Western Wisconsin DP Club Member

I was wondering how them two buggers worked together.Asked a few mechanics about the operation of two thermostats and just got funny looks.I thought one just backed the other one up.Wonder what happens if one sticks closed?
__________________
2007 Classic GMC D/A Ext. cab,s.b.,built 11-2006,Di*Priol boost and pyro gauges, Edge Insight CTS,Garmin GPS,MBRP catback exhaust,kitty taking a nap,300* hose permanent fix tranny cooling lines,M/A pump rub kit,Prodigy bc,Reese 16,000 lb. slider 4-way tilt hitch.Luverne SS side steps,Truxedo bed cover,Michelin LTX M/S 2 tires and Bilstein shocks.
Offline   Quick reply to this message
Old 04-24-2004, 11:48 PM   #4 (permalink)
hoot
Banned
 
hoot's Avatar
 
Join Date: Sep 2003
Posts: 4,583

GMworldclassmaster,

How does the turbo cooling bypass valve work?
Offline   Quick reply to this message
Old 04-25-2004, 05:03 PM   #5 (permalink)
Hit Man X
Diesel Head
 
Join Date: Mar 2004
Location: Mansfield, Texas, USA
Posts: 34
iTrader Score: 0 reviews
Send a message via ICQ to Hit Man X Send a message via AIM to Hit Man X Send a message via MSN to Hit Man X Send a message via Yahoo to Hit Man X

Hrm very interesting! Thanks!
__________________
Diesels are lazy, and they smoke.
Offline   Quick reply to this message
Old 04-26-2004, 09:22 AM   #6 (permalink)
ag4gt
Diesel Technician
 
ag4gt's Avatar
 
Join Date: Sep 2003
Location: Middle Georgia
Posts: 327
iTrader Score: 0 reviews

I dont know what happens when one stick closed but I had one stick open (or start opening at to low of a temperature). The engine takes a very long time to heat up and as soon as you come to a stop, like at a red light, the temperature drops about 20 degrees.
__________________
Steven
ag4gt311@gmail.com
'01 3/4 Ton Duramax/Allison Silverado &
'84 6.2L 1/2 Ton Silverado
I have done so much with so little for so long, I am now qualified to do everything with nothing.
Offline   Quick reply to this message
Sponsored Links
Advertisement
 
Closed Thread

Thread Tools

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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
dual thermostats wingman98 6.5L Diesel Engine 10 07-31-2011 02:48 PM
FS: 6.5TD Dual Thermostats - GM Pillow Closed / Archived Marketplace Ads 0 06-22-2011 10:46 AM
Dual Thermostats on a 6.2? palemale 6.2L Diesel Engine 20 12-28-2009 11:02 AM
Dual thermostats? ux4it 6.5L Diesel Engine 9 09-14-2008 06:12 AM
Dual thermostats! Ray,IN Duramax First Generation: 2001-2004 (LB7) 3 09-22-2006 12:22 PM


All times are GMT -4. The time now is 05:43 AM.


Shoutbox provided by vBShout v6.2.1 (Lite) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd. Runs best on HiVelocity Hosting.
© AutoGuide

SEO by vBSEO 3.6.0