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Losing Coolant When Towing

tanman_2006

tanman_2006

Just a farm kid...
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Location
Seiling, Oklahoma
I have put ~300 miles on the 06 LBZ w/ 171,000 miles pulling our swather around. The swather weighs in at ~18K and trailer another ~5K. runs 55mph in 4th like it theres nothing there (well you know what i mean).

Moving to a new field yesterday ~80* out side into 25mph head wind got the cooling fan to come on @230 and temps went back to normal boost was spiking 25 on hills low to mid teens normally. I coated the front of the swather in Antifreeze :mad2:.. I dont see any leaks but smell coolant in the engine bay. Added a gallon of water drove around all morning and the level never changed :skep: . The overflow tube is still full of dust and hasnt had water leaking out. Is it possible I have a bad radiator hose that isnt leaking until I get a large load on it?

Water pump is 7 months old ~20K miles.
 
I would start with changing the pressure cap on the reservoir. If your coolant was a good 50/50 mix to increase your boiling point to where it should be, its not now since you added water.
 
Gotta be a sign of where it came from. Pull the air box and look at the return hosefrom the overflow tank to see if it rubbed through on the CAC. I have a pic of that from mine but it's in my home box. Checc the EGR cooling line and down low on the driver's side on the block.
Look at this thread while you're at it.
 
Heater hoses esp at firewall. Heater core?

Small hole in radiator that normally just evaporates.

Air pocket in engine?

Defective new/reman waterpump? The seals can leak and then clear up for a little while.
 
Here's the overflow return under the air box. I got to mine with a piece of heater hose before it rubbed all the way thru.

Overflow.jpg
 
Thanks mike I say your thread when i searched and already checked that. I have rub makes but in no way are they through the hose.

Layed under the truck and pulled the skid plate to see/feel any moisture on the front (water pump area) and didnt get anything.

I was alil heavy on antifreeze (by over a gallon). The idiot that I had finish my WP R&R when i went out of town and didnt have time to finish kept adding coolant until it was full and I only got 1/2 gallon of water in after I got the air out.

Could the extra coolant cause the problem?

Pulled 40 miles today and didnt loose a drop! Its gonna drive me nuts....
 
tanman_2006 said:
Thanks mike I say your thread when i searched and already checked that. I have rub makes but in no way are they through the hose.

Layed under the truck and pulled the skid plate to see/feel any moisture on the front (water pump area) and didnt get anything.

I was alil heavy on antifreeze (by over a gallon). The idiot that I had finish my WP R&R when i went out of town and didnt have time to finish kept adding coolant until it was full and I only got 1/2 gallon of water in after I got the air out.

Could the extra coolant cause the problem?

Pulled 40 miles today and didnt loose a drop! Its gonna drive me nuts....
Click to expand...

Sure sounds like a water pump to me. Water pumps are famous for not leaking and then leaking BAD and then not leaking again until they finally let go and dump it all out in express fashion. Look for any signs of a yellow or brown powder below and behind teh water pump as DEX-COOL tends to leave rust like stains when it dries.
 
THEFERMANATOR said:
That don't mean it's still good. There are NUMEROUS problems with aftermarket and even some AC DELCO waterpumps on the LBZ going out in just a few days.
Click to expand...

X2. New problem. Never assume new parts are good parts.

I changed a leaking radiator out once. After everything was put back together the water pump was dumping coolant and then suddenly quit leaking. The seal manages to seal back up somehow.

Heater cores and radiators leak and then stop as debris can plug or nearly plug the hole for awhile.

If the heater core area and AC drain area is clear and the same for the radiator - I would suspect the water pump seal. You may have to remove the fan to get a good look at the radiator.
 
When there are no signs of losing coolant but its going and your head gaskets are ok this is a common symptom of duramax's especially the lbz's and only presents in trucks that are towing moderate to heavy loads or high hp/tq and being romped on.

you are losing coolant between the block and the rear cover where the trans bolts to. coolant flows through that rear cover and there are two orings that seal it to the block. when you are applying "a lot" of torque you get a small amount of separation between the block and rear cover and that 10-20 psi of coolant pressure pushes out. you can lose up to a cup on a decent uphill grade if you are towing a decent load.

i will try to find a picture of a test i did on a dyno to show this happening. i put my truck on a water load dyno used for testing semi-tractors with new motors under load. it applies a desired load consistently while you maintain desired power and speed.
 
Helluva call there Kyle. I had not heard of that before. Is there a fix? (No doubt it would be a good bit of labor). Or just be aware.
 
I saw some residue on the bottom of the tranny and wrote it off as being blown back there from a possible leak up front. I am going to say I have the bell housing leak.

I did find a spring clamp leaking that I will change for a good hose clamp.

I grossed 38K last night loaded with hay doing 60 mph. Is that considered moderate to heavy? lol
 
yep then thats yer problem right there. there is a solution but it is not worth it IMO. http://www.duramaxdiesels.com/forum/showthread.php?t=25476

you might be able to prevent it by using a heavier thickness o-ring but you have to pull the motor to replace them, and its not a fun job. when i built my motor i tried using grey rtv as well as the orings to provide a better seal and it did not work.
 
btfarm said:
Just make sure you can stop all that in a hurry Tanner. With that kind of load I'd stay below 60. WAY below....
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I normally stay 50-55 and not on heavily traveled roads. Based on power i could go 70 all day but stopping does worry me. My trailer isnt overloaded at that weight based on axles but the trucks springs are nonexistant at that point, time for custom springs and/or firestone air bags.
 
tanman_2006 said:
I was alil heavy on antifreeze (by over a gallon). The idiot that I had finish my WP R&R when i went out of town and didnt have time to finish kept adding coolant until it was full and I only got 1/2 gallon of water in after I got the air out.

Could the extra coolant cause the problem?
Click to expand...

Anti-freeze is not nearly as good as water for transferring heat, so your engine will tend to run hotter if there is not enough water in the mixture. If the seal leak is related to the temperature of the coolant, then I could see where this could make the leak worse.
 
i don't recommend firestone bags anymore after a bad experience, if i were you i would get a set of 3500 mason dump springs and overload bump stops. the only problem you will run into is your short bed frame does not have the pre drilled holes for the overload bumpstops. you will have to measure and drill your own.

as far as the firestone bags, i could never get one to pop as hard as i tried and i loaded up over 30k gross for thousands of miles. with the bags cranked all the way up around 90-110psi to prevent the 2500 springs from squatting, the ride was so stiff i bent the hitch (a class v reese titan) and the section of frame it was bolted to on a rough section of highway in nebraska.
 
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