Recently I had the head gasket and injector's and the cups replace due to a coolant leak. I've now had it back for about three wks and it still loosing coolant. The top hose is not hard after run for awhile and I've bought a new rad cap also and if you take the cap off while running there is no bubbles in the res. tank. I'm lost anybody got anything?

 

Well, think of all the places coolant goes and think of what signs it might leave. Start from the radiator and progress through each part of the entire engine back to the radiator. Did you have the head magnefluxed while it was off? (You would have mentioned that.) Apparently you don't have any overheating going on until the coolant is nearly gone.

Radiator: signs of leakage top, bottom, left, right, front back.

Lower radiator hose: Seepage at either end or drops in the middle. Sometimes leaks don't appear until the engine is good and warm.

Water pump: Leakage on the front of the engine.

Heater tubes: Rust and moisture.

Heater coil: Moisture in the cab floor or on the windshield when using the defroster.

Oil cooler: Moisture behind the oil filter mounting area, water in the oil.

Engine cooling jacket: Leaks at the front or back of the block, moisture in the tail pipe or steam in the morning with a cold engine, water in the oil. Also, super-heating the coolant and boiling it out while you drive.

Head gasket: (already changed) Water in the oil, super-heating the coolant and boiling it out while you drive, or leaking it into the oil.

Head: It might be warped and changing the gasket will not seal well around cylinders 3 & 4. A crack in the right place might cause coolant to get sucked into the cylinders with the intake air.

Thermostat: moisture around the thermostat housing.

Upper radiator hose: Moisture at either end or the middle.

Radiator cap: (already changed) coolant reservoir overfilling.

I have probably missed a couple coolant paths. Good luck. Sometimes coolant leaks are tough to find when they are not completely obvious.

Dean.

 

thanks bub I'll have to go through the list I'm just at my wit ends.

 

I've found the best way to inspect something is to clean it. Once you get inside wiping and brushing every part, you find things you didn't see when just observing it.

 

i would check your oil after letting it sit for a few days the coolant will settle on the bottom of the oil pan because it will seporate from the oil i would also take a oil scan and send it in to see what they say they find in your oil. it is possible there is pitting in one or more of the cylinder walls and its leaking in the small pin holes. if the wrong coolant was used or no coolant just straight water was used, pitting in the cylinder walls is very comnon in diesels. how fast do you loose the coolant? if your not noticing anyhing on the ground when its parked then i would say your probably burning it or evaporating it out of the engine.

 

i go through about 1 jug every 330 to 350 mi

 

That is a lot.

Have you tried running with the radiator cap loose? I've done that before to keep the internal pressure from building up and forcing coolant out.

If you are still losing coolant, then you could have a crack or gasket problem.
If you stop losing coolant, then you have a simple leak somewhere.

 

so your loosing a 1 gal around every tank of fuel? i would just start it on a clean cement pad and let it run for a hour or so and if you dont see any leaks on the ground. its going in your oil pan or your burning it, if you dont see anything on the ground obvoiusly. is it makind oil?

 

try putting a coolant pressure tester on it and watch for any leaks

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i also just checked gm tech web site check the egr cooler

 

get it pressure tested, how many miles are on the tuck right now?