Low coolant level

[DURAMAX HD 2001]

I have an 01 DMAX last week the low coolant light come on as I left home. I went back popped the hood and found the bottle a little low. I added coolant. Next day the light returned,found upper hose clamp loose,tighten clamp added coolant. Now after a few minutes of driving jud
st when it starts to warm up the heater goes cold and the guage will drop to 160 couple minutes later it will blow warm air and the guage will rise to 200 the fall back to 185. Sometimes at this point the coolant light comes on. I find coolant all over the right side from the tank. I acts like an air lock in the heater core. I bleed of the air and it still acts funny through the first warm up cycle. Seems to have good heat after that and the coolant res has not went low in last couple days. Did I fight an air lock or do I have compression in the block. Any word on injector cup or oring failure. Thanks for any help. This is the best site ever I used to have a user name back in 2001 but forgot it had to reenter. I have about 150,000 miles on her love the ol girl if she does not start costing money.

[DmaxMaverick]

Welcome to the Forums!

No big deal. You lost enough coolant with the leak to cause the issue. If the system is low, it will cavitate the water pump, and it won't prime, and cause the "steam purge" you experienced. When low, the super-heating of the coolant will cause what is in the lines to blow out the tank.

The system needs to be filled an bled. With that many miles, might as well do a flush and fill with fresh coolant and distilled water, or 50/50 premix (about 21 qts). The engine has coolant drain plugs on the left and right sides of the block, just above the oil pan near the front, and a radiator drain.

Bleeding is the key. There is a bleed port on the thermostat housing. Remove it, run the engine at idle until coolant flows w/o bubbles, all the while, keeping the coolant tank above the full level (gravity will help). Once the level stays, and you've replaced the plug, run the engine (tranny in P, with the E-brake on) up to 3000 RPM's (really...it won't hurt) and back to idle in 30 second intervals. Keep an eye on the tank, making sure it stays above the full level, leave the cap off during the process. Do this 3 times, or as many as it takes for the tank level to not move during the rev's. Check for leaks. Repeat the Rev process again once the engine is up to normal operating temp. Replace the cap. Normal aggressive driving will remove the remaining air, and may need to be replaced with coolant if the level gets too low, so keep some handy for a little while. Do not overfill the tank too much, as the excess will just blow out. 1/2" above the "full cold" mark is recommended.

Good luck!

[ 11-27-2005, 06:04 PM: Message edited by: DmaxMaverick ]

[DURAMAX HD 2001]

Thanks for the quick reply. I think this is all that is going on but I just had a hard time getting the air out. Fought it about 5 days total. I tryed to talk myself into compression issue. I will know more after the road trip tommorow. I have extra dexcool in the back. Gope she is ok. If she fails I will update.

[DmaxMaverick]

If you don't do the bleed and rev process, the air will not go away. Hopefully, you don't have other issues waiting to surface. These engines are as durable as they come, and stand up to some severe abuse. Please do report back your results. Good or bad.

[Kennedy]

I'm the pessimist who looks at the model year being 2001 and says head gasket(s) but hope it is not. The funky swings lend to alot of air in the lines which shouldpurge relatively easily to the surge tank. Start it up with the tank cap off and let it hit operating temp. Then put the cap on and see if it still gains pressure after a quick drive.

[Claven]

This is differnt but same topic,my 03 has blown coolant out 2 or 3 times but its only when I let it idle for long periods, I put a pepsi bottle on the overflow hose and It never caught a drop, even with a trip across Canada and back, but let it idle for more than an hour and it will push it out and if I watch the pressure jug I can see little bubbles, I dont suspect head gaskets, but I have read something about reseating the injector cups after having injectors replaced, can someone please explain this for me?

[DURAMAX HD 2001]

I preformed the bleeding procedure as described and got a lot of air out of the system. After I felt I had all removed that I could I let her set all night with the cap off. Next morning drove my 50 miles to work and back with no trouble. It has worked all week without any problems. Hope not to jinx myself here. Thanks for the info. I took the road away from optimistic and had myself talked into the worst.As far as blowing off at Idle I would think that cups or head gasket would do it during any engine speed. If it gets hot and blows off only at long idle maybe fan clutch?

[Claven]

Nope not fan clutch, I put electrics in and removed the factory fan, and I did this long after I noticed this problem, thanks though. I'm 99.9% sure it my injector cups after a bit more research.