LB7: Coolant leak.... [Archive] - Duramax Diesels Forum

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whitetrash21
10-24-2008, 07:46 PM
Had this problem for a few weeks. Truck uses about a gallon a week. Thought it might be an injector cup, but these pics says something else. Just saw all the fluid, have never seen it there before. I dont know if I missed it before or if it just started. Doesn't look like a surge tank lid to me as the tank top is clean... no dex stains there.

The first 6 pics are of the spray I can see on the motor and accesories. Drivers side is clean. Could this be the egr cooler doing this??? Heater core line??? Doesn't drip anything on the ground when i park it, but there definately is fluid sitting in there. Seems to me it's only leaking when I'm actually driving around, since if it leaked at idle , there'd be a puddle somewhere.....:confused: Not to mention that at idle, I cant see fluid coming from anywhere.

The last two pics I have no idea what that is. It's plumbed into the intake, and when I started the truck, it was moving in the direction the arrows show. It only did this for about 45 seconds or so and then stopped. It was suggested it be the egr opening and closing to help heat intake air up, thus warming truck?? Thoughts??

I hate emissions controls.....:o

Anyway, thanks for any help.

bullfrogjohnson
10-24-2008, 07:54 PM
have you put a bottle on the coolant tank line and driven it? It definatelt looks like you have some pressure behind that leak

whitetrash21
10-24-2008, 07:58 PM
Which line??? It looks to me like it's either pressure or else it only leaks when i'm actually driving it and the fan or wind is blowing the coolant all over the place....:confused:

Something like that

bullfrogjohnson
10-24-2008, 08:45 PM
Follow the overflow tank cap and there is a rubbe line that comes off and goes down the side of the tank and dumps off excess pressure. Put that line in a bottle and drive around. This will eliminate you pressurizing the collant system.

whitetrash21
10-24-2008, 09:13 PM
Roger. thanks. Try that tomorrow.

Jared Duramax
10-24-2008, 09:34 PM
take a look at your hard line that attatches to the motor from one of the heater core lines above the passanger side manifold i have seen these crack where they have the mount welded on them and cause leaks.

if you do find out you are getting coolant out of your overflow tube based on using a bottle let me know as i have just gone through all of this and feel confident about the cooling systems on an LB7

whitetrash21
10-25-2008, 10:00 PM
~60 miles today. No fluid in the bottle. I'll keep driving it, see if anything shows up.

Jared Duramax
10-25-2008, 10:10 PM
~60 miles today. No fluid in the bottle. I'll keep driving it, see if anything shows up.

how hard did you drive the truck during those miles?

whitetrash21
10-26-2008, 12:14 AM
I only have one way of driving... and that's drive the piss out of it. :D If something is gonna fail and not show, it WON'T be because I'm babying it.

TrentNell
10-26-2008, 12:40 AM
take a look at your hard line that attatches to the motor from one of the heater core lines above the passanger side manifold i have seen these crack where they have the mount welded on them and cause leaks.

if you do find out you are getting coolant out of your overflow tube based on using a bottle let me know as i have just gone through all of this and feel confident about the cooling systems on an LB7

x2 i bypassed the hard line and am now using soft line cause it will crack again if you replace it. my truck did the same thing and then one day it started leaking really bad.

whitetrash21
10-26-2008, 01:06 AM
Forgot to look at that today when plumbing the bottle.:o I'll check it tommorow. Thanks for the help guys.

sweetdiesel
10-26-2008, 01:14 AM
~60 miles today. No fluid in the bottle. I'll keep driving it, see if anything shows up.


thats good and a good test IMO I have a bottle that is used as a overflow constanlty on my one truck just incase it decides to blow coolant on my tires

You could try to pressure up the coolant tank to like 13 psi and let it sit over night and see what the pressure is in the morning if its down you could also pull glowplugs and fuse and then crank it over in the moring to see iff it blows coolant.

or have a real close look at all the coolant lines and water pump

Does it burn white at first start up?

LBZ
10-26-2008, 03:37 AM
I only have one way of driving... and that's drive the piss out of it. :D If something is gonna fail and not show, it WON'T be because I'm babying it.

Sounds like what Kurt said one time "If it ain't coming out of the driveway sideways with smoke rolling off the tires then it ain't me driving":rofl:

Jared Duramax
10-26-2008, 06:38 AM
That kind of sounds like me my truck has never had an easy day of driving:angel::driving:

whitetrash21
10-26-2008, 12:31 PM
thats good and a good test IMO I have a bottle that is used as a overflow constanlty on my one truck just incase it decides to blow coolant on my tires

You could try to pressure up the coolant tank to like 13 psi and let it sit over night and see what the pressure is in the morning if its down you could also pull glowplugs and fuse and then crank it over in the moring to see iff it blows coolant.

or have a real close look at all the coolant lines and water pump

Does it burn white at first start up?


No white smoke at all, even at a cold start. Temps been getting to ~50* here at night and when I start it in the morning, it sounds like an old 12v cummins... Still no white smoke and timing rattle goes away after about a minute of driving.

I checked anyplace coolant lines run on the front and drivers side... no leaks. I just replaced the pump about 15k miles ago. Pass side lines are all coated in Dex, but i cant tell where its coming from. Wipe it down, sdrive it and its all back:confused:

whitetrash21
10-26-2008, 10:58 PM
take a look at your hard line that attatches to the motor from one of the heater core lines above the passanger side manifold i have seen these crack where they have the mount welded on them and cause leaks.



Not quite sure which lines you are talking about. The two lines in Picture 3 are the heater core lines I'm seeing. One of them goes from the radiator directly to the firewall (the left one). The other does a loop and goes into what I'm seeing is the egr cooler (picture 1) ..... No signs of fluid leaking from any of the hose clamps/hose/hardpoints on any that I can see.

Got about 100 miles on total, still no fluid in the bottle.

sweetdiesel
10-27-2008, 07:30 AM
So the coolant that you are seeing is beig blown from the fan while driving I take it

Wes have you tried just pressuring the system and wiping off the hoses first

I think if you have a external leak that is probably a good thing as compared to internal leak

whitetrash21
10-27-2008, 05:58 PM
So the coolant that you are seeing is beig blown from the fan while driving I take it

Wes have you tried just pressuring the system and wiping off the hoses first

I think if you have a external leak that is probably a good thing as compared to internal leak

Thats what I'm assuming....:confused: Cant tell for sure though.

Haven't tried pressuring the system yet. What would I use to do that??? I have wiped the hoses down. Drove it right after that, flkuid all over them again. Can't tell where it's coming from since I cant see any leaks when it's idling.

You're right about the leak being external, just hope it's not a HG. I kinda doubt it would be as the fluid probably wouldn't be so high up on the motor. Seems to me a HG would be pushing fluid down the block or into the motor.

~200 miles now, still no fluid in the bottle.

Jared Duramax
10-27-2008, 06:07 PM
in your first picture you show the line going to the radiator this is the one i am talking about.

follow this line till it becomes an aluminum line that bolts to the motor

now where it bolts to the moter at there is a mounting bracket that is tig welded to the pipe

at the weld is where i have seen these leak at check this spot but you really need to pressurize the system in order to locate the problem because the fan really blows the coolant around

whitetrash21
10-27-2008, 06:14 PM
in your first picture you show the line going to the radiator this is the one i am talking about.

follow this line till it becomes an aluminum line that bolts to the motor

now where it bolts to the moter at there is a mounting bracket that is tig welded to the pipe

at the weld is where i have seen these leak at check this spot but you really need to pressurize the system in order to locate the problem because the fan really blows the coolant around

Gotcha. I'll check that out in a bit.
Where can I get the stuff to pressurize the cooling system?? Whats a safe pressure to hold it at???

whitetrash21
10-27-2008, 09:22 PM
This the line/hardpoint you talking about?? Looked ok to me. Charge tube under was clean, no dex on it. Line didn't feel cracked.....:confused:

sweetdiesel
10-27-2008, 10:27 PM
Somewhere on this site is a post and link for the coolant tester

Try and google a Dmac coolant tank pressure tester I think max is 13-15 psi
it just screws onto the cap for the overflow tank

you let it sit for a while and see if you can find a leak,the stock system should not exceed this as are stock cap blows off at like 13 psi IIRC

whitetrash21
10-27-2008, 10:59 PM
Something like this work???

http://www.toolsource.com/mv4529-cooling-system-pressure-tester-p-103506.html?sourceid=nextag

You think Harbor Freight might carry a cheapo version of that?? Thanks Simon:)

whitetrash21
10-28-2008, 05:36 PM
~420 miles on the bottle now and still nothing ... I think it's safe to assume that its not pushing out the overflow tube. Fresh spray on the firewall and filter housing though. Still no clue where it's coming from.

sweetdiesel
10-28-2008, 07:18 PM
~420 miles on the bottle now and still nothing ... I think it's safe to assume that its not pushing out the overflow tube. Fresh spray on the firewall and filter housing though. Still no clue where it's coming from.

Wish I could of made it 4.2 miles and my bottle was over flowing:(

I think your safe to say that:)



I seen you found a tool....its handy and I hope you find the leak with it

Jared Duramax
10-28-2008, 07:27 PM
Something like this work???

http://www.toolsource.com/mv4529-cooling-system-pressure-tester-p-103506.html?sourceid=nextag

You think Harbor Freight might carry a cheapo version of that?? Thanks Simon:)

that one wont work i bought that exact one and it wasnt it let me look in the napa catalogue and ill get you a part number

Jared Duramax
10-28-2008, 07:40 PM
SER3700 this will pressure test the cap and the tank (when you buy the adapter)

BK 7003025 this will also work as the pump for the tank but not the cap you can rent these from autozone or advanced i cant remember which one (still need the adapter)

BK 7003034 here is the adapter you need

These are all napa part numbers

sweetdiesel
10-28-2008, 08:14 PM
SER3700 this will pressure test the cap and the tank (when you buy the adapter)

BK 7003025 this will also work as the pump for the tank but not the cap you can rent these from autozone or advanced i cant remember which one (still need the adapter)

BK 7003034 here is the adapter you need

These are all napa part numbers

:rockon: Jared......good info!

Jared Duramax
10-28-2008, 08:17 PM
i went through all of this i bought 3 diffrent pressure testers to come up with what works but in the end it all got returned :D i will some day buy the correct tools

Jared Duramax
10-28-2008, 08:21 PM
the part numbers have been added to the Part numbers section:angel:

sweetdiesel
10-28-2008, 08:25 PM
the part numbers have been added to the Part numbers section:angel:

Cool as i use that for section for alot of my info

Jared Duramax
10-28-2008, 08:27 PM
Really?.......Me too!!:rofl:

whitetrash21
10-28-2008, 11:51 PM
SER3700 this will pressure test the cap and the tank (when you buy the adapter)

BK 7003025 this will also work as the pump for the tank but not the cap you can rent these from autozone or advanced i cant remember which one (still need the adapter)

BK 7003034 here is the adapter you need

These are all napa part numbers

Thanks a bunch for posting those. I'm going there tomorrow to pick up oil/filters... gonna see if I can pick one of these up.

One question: Will I be safe in purchasing the two BK parts only?? Seems to me if the cap was bad, it'd have coolant sprayed on the top of the tank or in the bottle (which it isnt) .....

Thanks again Jared and Simon. Really appreciate you helping me out....:hug::)

Jared Duramax
10-29-2008, 01:15 AM
i would probably say that the cap is fine but it probably wouldnt hurt to test it while you are at it. just remember that the cap blows off at 15 lbs and has a working pressure of 13 lbs

whitetrash21
10-29-2008, 01:50 AM
Ok. Will do. Thanks

clayt171
10-29-2008, 12:21 PM
Another way to try to pinpoint the leak is to use rags. Wire tie them in different areas to see where the spray is comming from. Be careful that they stay away from parts that get really hot or that move. Just attach them in various places and the one that is the wettest is the closest and what ever side has the most dex on it should point at the leaking area.

whitetrash21
10-29-2008, 09:30 PM
~550 miles, removed bottle and found leak. Stopped at Alligator today and we snooped for a bit. Turned out to be a hose located directly under the charge line coming from the turbo. I think it was part of the EGR cooler, not to sure about that though. Had a small crack in it, probably only opening when the EGR became active which would explain it not being found while idling.

Checked out those parts while at NAPA today. The Pump was ~$110 and the adapter was ~$70. Thanks for posting those.

Thanks to Chad also, for taking the time to help me. Appreciate it, bud. :hug::)

Jared Duramax
10-29-2008, 09:32 PM
i am glad to see that you figured it out. i know from experience that cooling issues suck but when they are fixed you feel so much better

whitetrash21
10-29-2008, 09:43 PM
Oh yeah :D

Now, how to get the jellified 5 gallons of coolant off the exh manifolds, down pipe, frame, trans pan, oil pan, heads, filter housing, etc, etc...... That stuff makes a mess and its nasty once its superheated.....

Jared Duramax
10-29-2008, 09:47 PM
Dawn and a pressure washer;) thats how i got mine off

whitetrash21
10-29-2008, 09:49 PM
I'll give that a shot. Thanks Jared.

Kat
10-29-2008, 10:15 PM
Good to hear that you got it fixed :D

Alligator
10-30-2008, 08:33 PM
That schiz is still on my hands? :rolleyes: Anytime Wes, thanks for helping with the tire rotation on the Rubicon.:hug:

Alligator
10-30-2008, 08:34 PM
~550 miles, removed bottle and found leak. Stopped at Alligator today and we snooped for a bit. Turned out to be a hose located directly under the charge line coming from the turbo. I think it was part of the EGR cooler, not to sure about that though. Had a small crack in it, probably only opening when the EGR became active which would explain it not being found while idling.

Checked out those parts while at NAPA today. The Pump was ~$110 and the adapter was ~$70. Thanks for posting those.

Thanks to Chad also, for taking the time to help me. Appreciate it, bud. :hug::)

It was part of the EGR cooler for sure Wes.

slowlmm
10-30-2008, 09:10 PM
That jiz is still on my hands? :rolleyes: Anytime Wes, thanks for helping with the tire rotation on the Rubicon.:hug:


:eek::rofl:

LBZrcks
10-30-2008, 09:15 PM
:eek::rofl:

:rofl::rofl::rofl::rofl:

sweetdiesel
10-31-2008, 08:20 AM
It was part of the EGR cooler for sure Wes.


Awsome News Wes! Now remove that silly EGR cooler:D

Jared Duramax
10-31-2008, 08:47 AM
EGR's are:gay:

Alligator
10-31-2008, 12:16 PM
:eek::rofl:

Nice Tommy, you got me haha:p