Disappearing coolant - Page 4 - Diesel Place : Chevrolet and GMC Diesel Truck Forums
 
Home Forum Market Place Garage Tuning Library DTC Tool Register Vendors
Go Back   Diesel Place : Chevrolet and GMC Diesel Truck Forums > GM Diesel Engines > 6.5L Diesel Engine
Register FAQ Forum Rules My Replies My Threads Advertise

6.5L Diesel Engine Discuss the 6.5 GM diesel engine & associated components. Automatic transmission questions & problems belong in the 4L80/85 - 4L60E - 6L90 Transmission Forum


DieselPlace.com is the premier Duramax Diesel Forum on the internet. Registered Users do not see the above ads.
Like Tree23Likes

Reply
 
LinkBack Thread Tools
Old 03-25-2020, 10:02 PM   #31 (permalink)
cruzer747
Diesel Fanatic
 
Join Date: Jan 2018
Location: No. California
Posts: 148
iTrader Score: 0 reviews

Quote:
Originally Posted by lukeenterprises View Post
Go to a stealership and get a package of this part number: 3634621. Take the radiator cap off when cold and put all of them in. Every 6.5 is supposed to have these. They are specifically for this promblem. The blocks have thin spots and also the head gaskets leak. These tabs are used in almost all the GM’s. No one will tell you this and most mechanics do not know about them.



My buddy was telling me about these pellets. Very interesting and probably a good preventative to keep from Little leaks turning into big corrosive issues. Anyways just a thought while I am lapping my valves right here. I am staring at small plugs in the head under each intake port. Potentially if you were having trouble tracking the leaked to one of the plates in the rear it could be in fact coming from one of these small plugs.

__________________
1994 GMC C3500 6.5L TD crewcab dually utility bed 311,XXX smiles 4" Diamond Eye exhaust, Hushpower muffler, Glowshift gauges, Lubrication Specialist ss oil cooler lines

Last edited by cruzer747; 03-25-2020 at 10:03 PM.
Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 03-26-2020, 12:02 AM   #32 (permalink)
cruzer747
Diesel Fanatic
 
Join Date: Jan 2018
Location: No. California
Posts: 148
iTrader Score: 0 reviews

Quote:
Originally Posted by bk95td View Post
I had it happen twice after only replacing the water pump and not putting a real gasket between the timing cover and block.
So I am reassembling my engine and am at this stage... from the factory there was no gasket. It calls for anaerobic flange sealant and activator. Being that I do not want a leak I am curious what you used. I do not mean to derail the thread and will delete if need be (however maybe it is the source of the leak!) At any rate, I was only able to find anaerobic gasket maker and activator locally. Tempted to try that and avoid the gasket.

__________________
1994 GMC C3500 6.5L TD crewcab dually utility bed 311,XXX smiles 4" Diamond Eye exhaust, Hushpower muffler, Glowshift gauges, Lubrication Specialist ss oil cooler lines
Offline   Reply With Quote Quick reply to this message
Old 03-26-2020, 12:42 AM   #33 (permalink)
Wreckinball67
Sparkplug Hunter
 
Join Date: Sep 2019
Location: No. Calif.
Posts: 1
iTrader Score: 0 reviews

I had a similar issue and discovered it was a cracked block.I have a 98' with only 93k miles and the #8 cylinder had a hairline crack near the top edge. I too was adding water/coolant for over a year. Obviously with only 93k miles I don't drive it often. The crack finally came to light because I didn't start the truck for over 2 weeks and when I finally went to start it, it hydro locked. I pulled all the glow plugs and cranked it over and discovered orange coolant coming from #8 cylinder.
I initially believed it was a blown head gasket and got prepared to replace the head gasket. Once I pulled the head and examined the #8 cylinder I noticed the hairline crack and it looked like perspiration on a very fine line.
I later learned about how this motor was prone to cracks in the rear cylinders due to lack of cooling in the rear cylinders.
I now have a new AM General Optimizer and have only put about 300 miles on it.
Good luck with your issue!
__________________
1998 6.5L
Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 03-26-2020, 02:21 PM   #34 (permalink)
asm225
Diesel Rookie
 
asm225's Avatar
 
Join Date: Nov 2015
Location: Walker, Louisiana
Posts: 36
iTrader Score: 0 reviews

Quote:
Originally Posted by cruzer747 View Post
At the hose coming out of the expansion tank near the radiator cap, (should be about am 8" section that will drain down the inner wheelwell.... put a small container (odwalla bottle or water bottle etc) around the drain hose. Drive it, when you are done with your drive, hop out and check it, if there is water in there then it is coming out the cap/overpressurizing/weak cap. It can be pretty hard to spot the evidence without catching it red handed like this.

If it is managing to burn that much water without pushing it somewhere else then I would think cracked head mostly behind an intake valve?
I did what you suggested, but there is no water in the water bottle. my radiator hose does not stiffen up immediately after starting the truck either. However, sometimes it will stiffen up while driving. this last time when I stopped the radiator hose was stiff. The cap was pressurized when I took it off, but that's not always the case. Still added a gallon of water.

There does not seem to be water leaking from the AC drain hole either

Some coolant splatter on the transmission pan is the only sign I can find
__________________
1994 EC 6.5L stock Dually
1996 EC 6.5 GMC C2500 Kojo tune on stock vacuum controlled turbo actuator, Bosch boost gauge with Glowshift Boost Bolt, 409K miles on stock engine, smokes like a steam boat since I purchased with 300k miles. Still running

Last edited by asm225; 03-26-2020 at 02:35 PM.
Offline   Reply With Quote Quick reply to this message
Old 03-26-2020, 02:46 PM   #35 (permalink)
cruzer747
Diesel Fanatic
 
Join Date: Jan 2018
Location: No. California
Posts: 148
iTrader Score: 0 reviews

Quote:
Originally Posted by asm225 View Post
this last time when I stopped the radiator hose was stiff. The cap was pressurized when I took it off, but that's not always the case. Still added a gallon of water.
That is a good sign, One last thing I can think of to rule out the water loss being a hg problem is to (make sure your radiator cap is clean and tight) after your next drive, hop out, feel for a stiff hose, then let it cool completely down... once cold the hose should again be soft.

Where I live at one of the major auto parts stores, we can rent tools for free (just need a deposit) and they have a cooling system pressure checker there that spins on like a T at the radiator cap and you pump it up like a bicycle tire and when it gets pressurized you may be able to see the water leaking out or hear it. That would be my next step.
__________________
1994 GMC C3500 6.5L TD crewcab dually utility bed 311,XXX smiles 4" Diamond Eye exhaust, Hushpower muffler, Glowshift gauges, Lubrication Specialist ss oil cooler lines
Offline   Reply With Quote Quick reply to this message
Old 03-26-2020, 04:15 PM   #36 (permalink)
Glagulator
Diesel Superstar
 
Join Date: May 2005
Location: Very south TEXAS, Formerly Wisconsin
Posts: 3,861
iTrader Score: 5 reviews

On the back of each head there is a cover plate with 2 bolts/studs that
covers the ports used by the coolant crossover on the front.
The one on the drivers side is below the glow plug relay.
You might check those for leakage.
They use the same gasket as the coolant crossover.
__________________
There are 10 kinds of people in this world; Those who understand binary and those who don't.

99 CREW LONG SRW C3500 work truck 199k+ mi. orig. motor & trans 4.10, modded engine harness, new oil cooler & lines, all new front end parts and poly bushings, trans poly mount, all new brakes.
96 SUBURBAN K2500 wife's truck 210k+ mi. orig. motor & trans, 3.73...
95 C2500 Suburban 6.5td HO w/p, timing set, HB & pulley, all rubber hoses, modded engine & main harness, converted to OBD2, PMD to bumper...
95 C1500 Suburban 6.5td rebuild tranny, convert to DB2, replacing as many parts as I can.
96 C2500 Suburban 7.4L converting to 6.5td w/ DB2, 4L80, 3.73
Offline   Reply With Quote Quick reply to this message
Old 03-27-2020, 12:06 AM   #37 (permalink)
bk95td
Diesel Prodigy
 
bk95td's Avatar
 
Join Date: May 2007
Location: =Annandale MN
Posts: 4,306
iTrader Score: 0 reviews

Quote:
Originally Posted by cruzer747 View Post
So I am reassembling my engine and am at this stage... from the factory there was no gasket. It calls for anaerobic flange sealant and activator. Being that I do not want a leak I am curious what you used. I do not mean to derail the thread and will delete if need be (however maybe it is the source of the leak!) At any rate, I was only able to find anaerobic gasket maker and activator locally. Tempted to try that and avoid the gasket.
I wouldn't use the anaerobic sealer. A gasket is foolproof and won't leak if you just replace the water pump in the future. My theory is that after so many heat and cool cycles, the mating surfaces are not perfect enough for anaerobic sealer only. Anarobic sealer gets very brittle with age and will crack when the water pump bolts are loosened.
__________________
91 K2500LD reg cab 6.2 4L60 deceased at 310k
92 k2500hd 6.5 4L80E std cab died of frame cancer285 k
4- 93 k2500hd 6.5 2-4L80E 2-NV4500 2-ex-cab 2 std
94 K2500HD 6.5td 4L80E new reman engine
94 K2500HD 6.5td NV4500 Std cab LB
2-94 K1500 Ex cab 6.5TD 4L80E 1-LB parts truck 1-SB
94 k25000 Suburban 6.5td 4l80E
95 tahoe 2 dr 6.5 4L80E needs HG or engine
95 k2500LD 6.5 4L80E std cab bad trans
95 k2500hd 6.5 4L80E ex-cab
2-95 K2500 Suburban 6.5TD 4L80E both need engines
97 k2500hd 6.5 4L80E std cab
97 k3500 C&C 6.5 4L80E std cab needs engine
98 k2500 hd 6.5 4L80E std cab bad trans
Offline   Reply With Quote Quick reply to this message
Old 03-28-2020, 02:37 AM   #38 (permalink)
Wooddog2010
Diesel Rookie
 
Join Date: Jul 2018
Location: TX
Posts: 37
iTrader Score: 0 reviews

I would bet to say that you do have a cracked head. The 6.5 are very prone to it. I was doing a rebuild at 230000 miles. Truck drove smooth before tearing down but did have that mysterious coolant disappearance. After doing precups I took it to have heads resurfaced and the machinist dusted the head. It had hairline cracks between the cylinders. He suggested either a new head or put irontite in it. So I opted for the irontite. It's really cheap.. 14$ the machinist had it on hand. So I knew then it was ok to use in my engine. Haven't had to fill coolant res since. I guess when your head is cracked like mine was. It goes out the tailpipe as vapor. Look up irontite. I used the reccomended all weather kind. Had clean coolant and used as indicated. He said not a permanent fix but he didn't want to take my money and scam me on resurfacing heads that were cracked. He said chances of finding used heads that weren't cracked is slim. ... new ones expensive. He said not to pet a dead horse but I love my 6.5 suburban
__________________
1995 6.5 turbo diesel suburban
Offline   Reply With Quote Quick reply to this message
Old 03-28-2020, 03:05 AM   #39 (permalink)
cruzer747
Diesel Fanatic
 
Join Date: Jan 2018
Location: No. California
Posts: 148
iTrader Score: 0 reviews

Quote:
Originally Posted by bk95td View Post
I had it happen twice after only replacing the water pump and not putting a real gasket between the timing cover and block.

So to be clear was this twice with anaerobic sealant or something else?
Or two different engines and water pump jobs?
__________________
1994 GMC C3500 6.5L TD crewcab dually utility bed 311,XXX smiles 4" Diamond Eye exhaust, Hushpower muffler, Glowshift gauges, Lubrication Specialist ss oil cooler lines
Offline   Reply With Quote Quick reply to this message
Old 03-28-2020, 10:06 AM   #40 (permalink)
guybb3
Diesel Veteran
 
Join Date: Feb 2004
Location: Tewksbury, Mass.
Posts: 5,860
iTrader Score: 0 reviews

Quote:
Originally Posted by MojaveMuse View Post
maybe the cap isn't seating right allowing the coolant to boil off and escape?
No, mine is loose all the time and it didn't lose any until the water pump REALLY started leaking

__________________
96 1500 4x4 suburban F-series engine
3 to 4 inch exhaust
Oilguard bypass oil filter with additional permacool dual remote oil filters adapted to take two 1 1/2 quart Mobil 1 m1-403 filters---10.5 quart capacity now
B&M Deep Tranny Pan
Remote fuel filter with 1R-0749 CAT 2 micron filter or Donaldson P551000 and 200 watt electric pad heater
Walbro FRB-5 Lift Pump
Dipaco Remote FSD with #9 resistor behind bumper
1999 High capacity (opt K47) Air box-Amsoil EaO filter
AT&T Turbo-Vacuum pump deleted
4 wheel disc brakes-4 headlight on Mod
Member #1 of The Diesel Place Black Belt Club
---------------------
got RXT X 300? hang on!!
Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Diesel Place : Chevrolet and GMC Diesel Truck Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

PLEASE READ! You must check your email inbox for the confirmation link to complete registration. Please check your spam box if you do not see the email in your inbox.

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 email address for yourself.
Email Address:

Log-in



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



All times are GMT -4. The time now is 07:50 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Shoutbox provided by vBShout v6.2.1 (Lite) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd. Runs best on HiVelocity Hosting.
© AutoGuide