Rays01

I am at my hair ends with this problem. My truck even after being plugged in all night will heat up driving down the road about 5 miles from home and peg the gauge and puke antifreeze all over the place. Then the temp gauge will drop and I have no heat as it goes low on coolant. I pulled the radiator and cleaned out the oil crud and relocated the breather tube to back of motor, changed the thermostat to a stant 190 as it was the only one available even from cummins. Changed to a new 16 pound cap, and filled up with all new antifreeze and water at a 50/50 mix. I keep going threw this overheat and refill cycle and Im going broke from buying antifreeze. After I have overheated and refill the radiator, my heater works fine and it stays put at around 190 degrees. Help.....

slim51015

Check your T-stat again if not that, could be waterpump

J BODY

As rare as it is I would be pulling the waterpump off and taking a look. Impeller may be broken away from the shaft.

Rays01

I can see water coming threw the radiator fins when the stat is open. would a busted water pump still do that? It almost acts like the motor comes up to temp but the thermostat is to slow to react. Im ready to trade it in for a mexican blanket and a burro.

Jim Dynomite

Blown head gasket?

...................Jim

Rays01

I do not see any external leakage or water in the oil.

Marine

Are you sure you are getting all the air out of the system?

Jim Dynomite

What about exhaust gas entering the cooling system from the blown head gasket and presurizing the cooling system?

Would this blow your coolant out?

.........Jim

JPR Ram

my money is on the water pump

Rays01

How do you make sure all the air gets out of the block? I fill the radiator up adn it stays put with no bubles etc. Then it starts slowly spilling out until the stat opens, I top it back off and toss the cap on. then as it comes back up towards opening temp again it starts pushing it back in threw the overflow bottle. It does pull antifreeze back out of the bottle but it doesnt fill the system up enough to stay cool. How do I test for a blown head gasket? The cooling system retains preasure over night. wouldnt it bleed down over a few hours? Is a failed water impeller a common enough problem to warrant pulling apart the motor? Thanks for all the help.

J BODY

Well it's sounding more like pulling the water pump may be a waste of time. If you top it off, put the cap on, start the engine....does it build psi fairly quick?

...if so I would suspect combustion gasses are going into your cooling system.....of course, if it holds psi overnight that kind of blows holes in that theory too. Normally if there is a way for combustion gasses to enter the cooling system, once you shut the engine down the pressurized cooling system will then push coolant into the crankcase via the same "leak" where the combustion came from. Keep us updated please....this is an interesting one.

PChouinard

How long has this been happening? Was there any significant repairs or maintenance done prior to this symptom? This may sound stupid, but is your t-stat in upside-down? Definately a tuffy. GL

Rays01

Ok, went and bought another thermostat (napa) 190 degree. It has a brass plug extending off the bottom I am assuming it plugs one of the water ports. While I had the stat out I completly filled the block up with coolant until it was spilling out the open radiator. put it all back together. Its still doing the same thing. It will go from 190 to pegging out the gauge in about 10 seconds and trip the check gauge light. Then it drops back down to 190 about 30 seconds later and settles there for awhile. I know it gets that hot as the cap blows all over. Im lost. Im ready to jerk the radiator out and try flushing the fins out somehow. And yes the stat is in the correct position. I have done no major repairs lately and the oil is within 500 miles of just changed. Its still not showing any moister in oil or exhaust.

yfz450guy

if you want to flush the rad you may want to try this trick i learned during my long haul days.
It’s Cascade! Just put 1 cup into radiator and idle for 15 min. Then flush by running straight water for 10 min. twice and on the last one open the drain while running the hose into the radiator cap hole, making sure that its over flowing and the truck is running. Close the drain and wait a couple of min. to let the truck cool garden hose turned off. Drain the water and fill with 50/50 mix. Remember that it takes coolant about 100 miles of driving to mix if you don’t mix it outside the radiator, or you can buy premix.

Rays01

dishwasher detergent? Thats an iteresting idea. Do I drain all antifreeze out first or add detergent to it before flushing it out? I may try that out.