TheDieselPage.com Forums
 
The Diesel Page Forums

2020 - TDP's 24th Anniversary
What's New | Feature Articles | Product Reviews | Member's Area | Free Forum Registration
Duramax 6600 Diesel Page | Advertiser's Section | Classified Ads | The Diesel Page - Publications


Go Back   TheDieselPage.com Forums > The Diesel Page Forums > 6.5L Turbo Diesel - Tech Support - Troubleshooting - Performance

6.5L Turbo Diesel - Tech Support - Troubleshooting - Performance 1992-00 6.5L Turbo Diesel - Welcome to the Internet's first discussion forum for the 6.5L diesel engine. Tips on performance, upgrades, cooling, fuel economy, troubleshooting and more.

Reply
 
Thread Tools Display Modes
  #1  
Old 09-01-2020, 10:23 PM
rnash4's Avatar
rnash4 rnash4 is offline
"Ate Up With It"
 
Join Date: Dec 2010
Location: SE Texas
Posts: 59
Default Regarding '97 Cooling Mod

In another forum this statement was made recently by one of their "gurus"....."Running the dual t-stat setup without the BRF (bypass restrictor fitting) tends to cook the #7 and #8 cylinders." And it was stated as an undisputed fact. Wasn't this the reason GM designed the '97 cooling upgrade (w/o BRF) to begin with? To stop head cracking and cooking the rear cylinders? And increasing flow through the heads and block by 74%?
__________________
'95 GMC Sierra 6.5TD C2500, reg cab, long box, 2x4, 4L80E, 3.73 ratio, VIN F, L65, 120K. Mods: DE 4" exhaust/crossover, WW2, PMD relocate, Dmax fan/clutch, HP air filter, Fluidampr, B&M Trans/Diff covers.
Reply With Quote
  #2  
Old 09-01-2020, 10:46 PM
DmaxMaverick's Avatar
DmaxMaverick DmaxMaverick is offline
Administrator
 
Join Date: Apr 2001
Location: CA
Posts: 12,751
Default

Yeah, because more coolant flow results in greater heat. (not)

The "theory" may sound good, but it only looks good on a temp gage. It's the same heat. If you aren't seeing it on the gage, it went somewhere (or, in fact, didn't go anywhere, which is the problem). All else being equal, a higher reading from a temp sender shows more heat moved away from the source. Isn't that exactly what we are trying to do? Hogwash, at its best. The same applies to the "rear head coolant bypass". If you feel better that your gage is indicating a lower temp, you're talking to the wrong end of the horse.
__________________
1985 Blazer 6.2
2001 GMC 2500HD D/A
2014 Chevy Cruze Diesel - Fabulous car, no problems at all, but sold Nov. 2016 @ 55K miles.
dmaxmaverick@thedieselpage.com
Reply With Quote
  #3  
Old 09-02-2020, 03:22 PM
rnash4's Avatar
rnash4 rnash4 is offline
"Ate Up With It"
 
Join Date: Dec 2010
Location: SE Texas
Posts: 59
Default

Quote:
Originally Posted by DmaxMaverick View Post
Yeah, because more coolant flow results in greater heat. (not)

The "theory" may sound good, but it only looks good on a temp gage. It's the same heat. If you aren't seeing it on the gage, it went somewhere (or, in fact, didn't go anywhere, which is the problem). All else being equal, a higher reading from a temp sender shows more heat moved away from the source. Isn't that exactly what we are trying to do? Hogwash, at its best. The same applies to the "rear head coolant bypass". If you feel better that your gage is indicating a lower temp, you're talking to the wrong end of the horse.
Some other sites do have some good info, but a lot of it is aftermarket huckster BS. Lol. This site tends to keep me grounded with honest practical information. Thanks for the reply Dmax.
__________________
'95 GMC Sierra 6.5TD C2500, reg cab, long box, 2x4, 4L80E, 3.73 ratio, VIN F, L65, 120K. Mods: DE 4" exhaust/crossover, WW2, PMD relocate, Dmax fan/clutch, HP air filter, Fluidampr, B&M Trans/Diff covers.
Reply With Quote
  #4  
Old 09-02-2020, 04:29 PM
56pan 56pan is offline
Enthusiast
 
Join Date: Feb 2006
Posts: 114
Default

I saw the same post on that forum that rnash4 quoted. My BS detector pegged in the red. Thank you Dmax for a lucid and common sense explanation of this issue.
Reply With Quote
  #5  
Old 09-15-2020, 08:37 AM
Kennedy Kennedy is offline
Long Distance Crew Chief for BMDMAX
 
Join Date: Mar 2000
Location: Loyal WI US
Posts: 10,769
Default

Quote:
Originally Posted by rnash4 View Post
In another forum this statement was made recently by one of their "gurus"....."Running the dual t-stat setup without the BRF (bypass restrictor fitting) tends to cook the #7 and #8 cylinders." And it was stated as an undisputed fact. Wasn't this the reason GM designed the '97 cooling upgrade (w/o BRF) to begin with? To stop head cracking and cooking the rear cylinders? And increasing flow through the heads and block by 74%?
100% Pure BS from an untrustworthy vendor likely from TX who just happens to make said restrictor. This and the "balanced flow" water pump claim make me want to kick these guys in the nuts...

P.S. It's been a while since I have handled one, but I believe the bypass was enlarged on these compared to prior models.
__________________
Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
Reply With Quote
  #6  
Old 09-15-2020, 09:51 AM
rnash4's Avatar
rnash4 rnash4 is offline
"Ate Up With It"
 
Join Date: Dec 2010
Location: SE Texas
Posts: 59
Talking

Quote:
Originally Posted by Kennedy View Post
100% Pure BS from an untrustworthy vendor likely from TX who just happens to make said restrictor. This and the "balanced flow" water pump claim make me want to kick these guys in the nuts...

P.S. It's been a while since I have handled one, but I believe the bypass was enlarged on these compared to prior models.
Just yesterday he told a guy to add the BRF to "balance the flows" to prevent cooking the 7 & 8 cylinders! LOL (It wasn't the vendor from Tx)
__________________
'95 GMC Sierra 6.5TD C2500, reg cab, long box, 2x4, 4L80E, 3.73 ratio, VIN F, L65, 120K. Mods: DE 4" exhaust/crossover, WW2, PMD relocate, Dmax fan/clutch, HP air filter, Fluidampr, B&M Trans/Diff covers.
Reply With Quote
  #7  
Old 09-15-2020, 01:30 PM
Robyn's Avatar
Robyn Robyn is offline
Missy Good Wench ( Moderator)
 
Join Date: Apr 2001
Location: Newberg Oregon
Posts: 10,827
Default

There has been more hocus pokus about the cooling system on the 6.5 than I care to hash out

The GM update to the dual stats and high volume pump worked pretty well.....

Even the original single stat and standard pump was not too bad as long as the radiator was in good shape and the fan clutch was working right....

The rear two cyl's were set with .0005" (Half thou) more clearance on the pistons.....
__________________
(1) 1995 Suburban 2500 4x4
(1) 1997 Astro
(1) 2007 Chevy Avalanche
THIS IS BOW TIE COUNTRY
Reply With Quote
  #8  
Old 09-15-2020, 02:49 PM
sctrailrider's Avatar
sctrailrider sctrailrider is offline
Diesel junkie
 
Join Date: Feb 2012
Location: Pauline, SC
Posts: 552
Default

It wasn't the one from SC either, I call the others out when ever I see those stupid post...
__________________
1993 Chevy K3500

owner - Twisted Steel Performance

porting, ceramic & powder coating

like us on Facebook
Reply With Quote
  #9  
Old 09-15-2020, 03:13 PM
Robyn's Avatar
Robyn Robyn is offline
Missy Good Wench ( Moderator)
 
Join Date: Apr 2001
Location: Newberg Oregon
Posts: 10,827
Default

The part that sucks is that GM should have cast the heads to flow better .....

The 6.5 Turbo cooling system was/is always right on the ragged edge of NOT ENOUGH.....Even when new.

Add some miles and crap in the cooling stack and all bets are off.

Another Fubar was that GM had some really good fan clutches back in the 80's that really came on and would howl like hell until the temps were where they belonged.

People started whining about the noise...so GM bumped the lockup temp up some.

Ya really had to get them cooking hot to get the clutch to bring the fan on hard.

So a whole batch of rigs were unfit to cool well because of whiners.....

Also...many folks would take their rig in complaining the the tranny was slipping.

I got into one of those bru ha ha's

Customer kept telling me his tranny was slipping

No factory tach.

Installed a tach and romped the rig until all of a sudden the fan started howling like a banshee.

Tach was rock solid....Customer screamed to hell and back.

I bought the rig off him ...Had 20k miles (K2500 Burb)

I ran it 250K miles with zero issues....350 V8 TH400

Sweet truck

Gm's decision to cave to stupid customers instead of educating them was a dumb move..
__________________
(1) 1995 Suburban 2500 4x4
(1) 1997 Astro
(1) 2007 Chevy Avalanche
THIS IS BOW TIE COUNTRY
Reply With Quote
  #10  
Old 09-16-2020, 09:11 AM
Yukon6.2 Yukon6.2 is offline
Enthusiast
 
Join Date: Dec 2003
Location: Yukon Canada
Posts: 1,172
Default

That's the biggest problem...
Education
Nobody does it anymore,just build everything and make rules for stupid humans.
__________________
90 Chev 3500 c/c 4x4,6.2na,400 auto,4:10 gears.DSG Timing gears,main girdle, isspro tach, pyro,boost,oil and trany temp.Dual Tstats, High volume peninsular pump,on shelf, Custom turbo and intercooler 85%complete. Change of plans for the dually, it's going to get a Cummins. Both trucks are Blue 90 4x4 crews
Reply With Quote
  #11  
Old 09-16-2020, 11:02 AM
Robyn's Avatar
Robyn Robyn is offline
Missy Good Wench ( Moderator)
 
Join Date: Apr 2001
Location: Newberg Oregon
Posts: 10,827
Default

Far too many people know absolutely NOTHING about the rig they drive and they are the ones that bitch the most.

The old fan clutches were great./

When the temp got just a whisker above the 190 F mark the fan howled...

That was a great setup.

AND IT WORKED WELL.

Now they put the RED ZONE on the gauge at 260 F

Wrong answer....
__________________
(1) 1995 Suburban 2500 4x4
(1) 1997 Astro
(1) 2007 Chevy Avalanche
THIS IS BOW TIE COUNTRY
Reply With Quote
  #12  
Old 09-17-2020, 09:48 AM
Kennedy Kennedy is offline
Long Distance Crew Chief for BMDMAX
 
Join Date: Mar 2000
Location: Loyal WI US
Posts: 10,769
Default

If I had a 93-96 with single stat and no dual stat setup I'd consider running the big water pump and REMOVE the bypass block off on the OE thermostat.
__________________
Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
Reply With Quote
  #13  
Old 09-17-2020, 03:40 PM
rnash4's Avatar
rnash4 rnash4 is offline
"Ate Up With It"
 
Join Date: Dec 2010
Location: SE Texas
Posts: 59
Default

Quote:
Originally Posted by Kennedy View Post
If I had a 93-96 with single stat and no dual stat setup I'd consider running the big water pump and REMOVE the bypass block off on the OE thermostat.
I have been thinking about doing that on my '95. I don't pull heavy and no cooling issues so far. But whenever my pump needs replacing sure would like to put the HO unit on, less the bypass block off.
__________________
'95 GMC Sierra 6.5TD C2500, reg cab, long box, 2x4, 4L80E, 3.73 ratio, VIN F, L65, 120K. Mods: DE 4" exhaust/crossover, WW2, PMD relocate, Dmax fan/clutch, HP air filter, Fluidampr, B&M Trans/Diff covers.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Cooling Mod, Heater Core Supply Tube johnanc 6.5L Turbo Diesel - Tech Support - Troubleshooting - Performance 1 11-18-2006 12:00 AM
Removal of theoretical cooling #8 & #6 cylinders mod john8662 6.5L Turbo Diesel - Tech Support - Troubleshooting - Performance 62 06-20-2005 07:32 AM
97 cooling mod update 6.542762mw 6.5L Turbo Diesel - Tech Support - Troubleshooting - Performance 1 05-16-2005 07:58 PM
GM 6.5 Cooling Mod Kit Mike Dutton 6.5L Turbo Diesel - Tech Support - Troubleshooting - Performance 3 02-27-2005 08:06 AM
What does it honestly take to run a 14.0 with a Duramax? McRat Duramax 6600 50 08-22-2003 09:15 AM


All times are GMT -7. The time now is 01:24 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Copyright 1996-2020 by TheDieselPage.com - All Rights Reserved