Cooling System Refuses to bleed

[Lifted92]

I have a 2007 Dodge ram 2500 with the 5.7 Hemi. A couple weeks ago I replaced the water pump due to the bearing going out, I also replaced the Thermostat while I was there. Filled the radiator and puke tank and let the pickup get up to temp with the radiator cap off. Thermostat opened around 205° and sucked coolant down, it was refilled and the cap was put on whenever it leveled off and the heat was hot.

Fast forward to the next day and I lose heat during the massive cold spell and have never gotten it back. I have tried the same bleeding procedure about 3 more times to no avail. During this time the engine ran normal temp with no other issues.

Now a couple days ago after using the pickup for over an hour it overheated on the highway and I cannot make it more than 2-3 miles without this thing overheating. We have since used a pressure bleeder to pull the air out of the system with a vacuum and replace it with coolant and it didn't seem to help in any way. while it was sitting there idling the coolant/engine never overheated but it kept surging out and never really leveled out, however the heater actually got hot this time. Put a new radiator cap on, the system pressurized and I drove it less than 1/4 mile and it overheated again and lost heat in the heatercore at the same time. I know there is flow through the thermostat from when we bled it last but I am completely lost on what to try now.

Does anyone have any ideas what could be the issue and/or how to solve it? Thanks in advance for any help, it sure is appreciated

 

[Fast69Mopar]

I have a 2007 Dodge ram 2500 with the 5.7 Hemi. A couple weeks ago I replaced the water pump due to the bearing going out, I also replaced the Thermostat while I was there. Filled the radiator and puke tank and let the pickup get up to temp with the radiator cap off. Thermostat opened around 205° and sucked coolant down, it was refilled and the cap was put on whenever it leveled off and the heat was hot.

Fast forward to the next day and I lose heat during the massive cold spell and have never gotten it back. I have tried the same bleeding procedure about 3 more times to no avail. During this time the engine ran normal temp with no other issues.

Now a couple days ago after using the pickup for over an hour it overheated on the highway and I cannot make it more than 2-3 miles without this thing overheating. We have since used a pressure bleeder to pull the air out of the system with a vacuum and replace it with coolant and it didn't seem to help in any way. while it was sitting there idling the coolant/engine never overheated but it kept surging out and never really leveled out, however the heater actually got hot this time. Put a new radiator cap on, the system pressurized and I drove it less than 1/4 mile and it overheated again and lost heat in the heatercore at the same time. I know there is flow through the thermostat from when we bled it last but I am completely lost on what to try now.

Does anyone have any ideas what could be the issue and/or how to solve it? Thanks in advance for any help, it sure is appreciated

In a situation like this the first thing I do is remove the thermostat and see if it remedies the problem. The engine will take longer to warm up without the thermostat installed. After the thermostat has been removed top off the cooling system and go drive it and see if it overheats.

I do it this way to eliminate the thermostat from the diagnosis and focus on the remaining pieces of the cooling system.

 

[Dan98]

I have a 2007 Dodge ram 2500 with the 5.7 Hemi. A couple weeks ago I replaced the water pump due to the bearing going out, I also replaced the Thermostat while I was there. Filled the radiator and puke tank and let the pickup get up to temp with the radiator cap off. Thermostat opened around 205° and sucked coolant down, it was refilled and the cap was put on whenever it leveled off and the heat was hot.

Fast forward to the next day and I lose heat during the massive cold spell and have never gotten it back. I have tried the same bleeding procedure about 3 more times to no avail. During this time the engine ran normal temp with no other issues.

Now a couple days ago after using the pickup for over an hour it overheated on the highway and I cannot make it more than 2-3 miles without this thing overheating. We have since used a pressure bleeder to pull the air out of the system with a vacuum and replace it with coolant and it didn't seem to help in any way. while it was sitting there idling the coolant/engine never overheated but it kept surging out and never really leveled out, however the heater actually got hot this time. Put a new radiator cap on, the system pressurized and I drove it less than 1/4 mile and it overheated again and lost heat in the heatercore at the same time. I know there is flow through the thermostat from when we bled it last but I am completely lost on what to try now.

Does anyone have any ideas what could be the issue and/or how to solve it? Thanks in advance for any help, it sure is appreciated

You should have heat regardless of open or closed thermostat. Did the truck overheat when the original pump bering went out?? What your explaining sounds like pressure building in cooling system from the combustion chamber.

Sent from my SM-J260A using Tapatalk

 

[ViolentMouse]

I never saw any mention of opening the bleed screw during filling?

Did your new thermostat have a tiny hole in it? if not, I always suggest making a single 1/8 hole near the top of any T-stat to allow air to escape.

There is a bleed screw, that must be open when you fill the system with coolant, and when the system is full, coolant will come out of said bleed hole. reinstall bleed screw, continue to top off.

When you had the pump off, did you check for erosion behind the pump? if the timing cover was badly rotted out, a new pump can spin all it wants and still barely move fluid.

Losing heat, could be a lack of flow, a huge air pocket.

Knowing you have overheated it, and still have overheating issues, you need to go to NAPA and get an engine block test kit. It comes with a blue fluid, that changes color when it detects combustion gasses.

You will remove some coolant from the vehicle so it doesn't push coolant into the tester and contaminate the fluid. Put the tester in the coolant filler neck and fire up the vehicle, if the fluid in the tester turns from blue to yellow, you popped the head gaskets when you overheated it. if it does not change colors, then try a new T-Stat and bleed the motor properly from the bleed port when filling.

 

[Dodge 1500 4X4]

What condition is your radiator in, check your temp with a IR temp gun your top hose temp will be hotter being returned from the block, and your lower will be cooler being cooled by the fan and the radiator, if its the same temp suspect a clogged radiator core.

 

[Lifted92]

You should have heat regardless of open or closed thermostat. Did the truck overheat when the original pump bearing went out?? What your explaining sounds like pressure building in cooling system from the combustion chamber.

Sent from my SM-J260A using Tapatalk

The water pump bearing never actually went out in a dramatic way or anything. I happened to catch it by grabbing the fan one day and it had some wobble to it. Before replacing the water pump everything worked 100% everything started once the pump was replaced.

 

[Lifted92]

What condition is your radiator in, check your temp with a IR temp gun your top hose temp will be hotter being returned from the block, and your lower will be cooler being cooled by the fan and the radiator, if its the same temp suspect a clogged radiator core.

I can physically feel the top hose is quite a bit hotter after the engine is up to temp, so the radiator is doing it job and it worked just fine all the way up until I replaced the water pump

 

[Lifted92]

I never saw any mention of opening the bleed screw during filling?

Did your new thermostat have a tiny hole in it? if not, I always suggest making a single 1/8 hole near the top of any T-stat to allow air to escape.

There is a bleed screw, that must be open when you fill the system with coolant, and when the system is full, coolant will come out of said bleed hole. reinstall bleed screw, continue to top off.

When you had the pump off, did you check for erosion behind the pump? if the timing cover was badly rotted out, a new pump can spin all it wants and still barely move fluid.

Losing heat, could be a lack of flow, a huge air pocket.

Knowing you have overheated it, and still have overheating issues, you need to go to NAPA and get an engine block test kit. It comes with a blue fluid, that changes color when it detects combustion gasses.

You will remove some coolant from the vehicle so it doesn't push coolant into the tester and contaminate the fluid. Put the tester in the coolant filler neck and fire up the vehicle, if the fluid in the tester turns from blue to yellow, you popped the head gaskets when you overheated it. if it does not change colors, then try a new T-Stat and bleed the motor properly from the bleed port when filling.

The thermostat did have a small brass "valve" that lets air through to help bleed it, and as far as I can tell, on these 3rd gen truck Hemis there are no bleeder screws or anything similar like there is on the 4th gens.

When we had the pump off everything looked almost pristine, I made sure to dry coolant out of passages and blow them out along with scraping the mating surface clean with a razor blade.

When it overheated it got only to the point where the check gages light dinged at me and I immediately shut it off and coasted to a stop on the side of the road, so it never got dangerously hot. I have since checked the oil and coolant and there is no milkshake whatsoever which leads me to believe that the head gasket isn't blown or anything. However, when the pickup is idling when we try to bleed it, a few quarts of coolant gets pushed out of the radiator (we were able to use a funnel and make a seal acting like an expansion tank so none of it overspilled on the ground) and if it is shut off then is sucks the coolant back into the system.

 

[Lifted92]

Thanks for the help on this guys, but the plot thickens as we have found some more strange symptoms. We replaced the new thermostat with a new NEW thermostat hoping that might be part of the issue but it was not. But we have noticed the following things,

1. The passenger side heat gets hot but the driver doesn't. if you switch the location it blows it will get cool on both sides until the engine hits about 3000-4000 RPM and the passenger side will get hot again

2. The last test drive it got hot (halfway between operating temp ang H on the gauge) but it never did over heat

3. When I would stop and take off hitting 5000+ RPM I could physically see the temp gauge drop by a small margin

At this point the only thing we can possibly figure is that maybe the impeller is slipping on the shaft and not moving enough coolant combined with a large air pocket.

Anyone wanna buy a truck? LOL

 

[RonJon '06]

Is it possible the thermostat was installed upside down? If you end up replacing the water pump again there should be a bleeder screw on the front though I've never actually used it. If it's just a stubborn air pocket the other thing you can try is have the truck parked on an incline with the nose up when bleeding the air out of the system. Good luck!

 

[Lifted92]

Is it possible the thermostat was installed upside down? If you end up replacing the water pump again there should be a bleeder screw on the front though I've never actually used it. If it's just a stubborn air pocket the other thing you can try is have the truck parked on an incline with the nose up when bleeding the air out of the system. Good luck!

The 2nd thermostat we installed I made sure the little brass valve and hole was at the top. I've also looked this thing up and down and I cannot find any bleeder screw like the 4.7s have or the newer 5.7s have. The link is to the water pump I got and as far as I can tell there is no bleeder there either. We'll try bleeding it on an incline next time

https://www.oreillyauto.com/detail/...-new/cp7168/4526128/2007/dodge/ram-2500?pos=1

Thanks for your help!

 

[alpinegreenneon]

There is a tool called the UView Airlift that is recommended by FCA for several of their other vehicles. Other manufacturers also recommend it. It uses compressed air to make a vacuum, then you insert a hose into a bucket of coolant and turn a valve and it sucks in the coolant without any air bubbles. There is a gauge that shows if the cooling system will hold a vacuum. If it doesn't, there is a leak somewhere. I have one that I bought on an eBay auction used for $40. It works the first time with no need to check the next day.
There are a bunch of YouTube videos about it.

 

[Lifted92]

There is a tool called the UView Airlift that is recommended by FCA for several of their other vehicles. Other manufacturers also recommend it. It uses compressed air to make a vacuum, then you insert a hose into a bucket of coolant and turn a valve and it sucks in the coolant without any air bubbles. There is a gauge that shows if the cooling system will hold a vacuum. If it doesn't, there is a leak somewhere. I have one that I bought on an eBay auction used for $40. It works the first time with no need to check the next day.
There are a bunch of YouTube videos about it.

That is the pressure bleeder I was referring to, The instructions said to let it pull to 23inHG, however we could only pull 20inHG & hold before the upper and lower hose collapsed because there aren't springs in them. It didn't seem to make any difference at all

https://www.oreillyauto.com/detail/...95/2007/dodge/ram-2500?q=coolant+vacuum&pos=7

 

[alpinegreenneon]

Does your tool show that your cooling system holds vacuum? It's normal for the hoses to collapse.

 

[Lifted92]

Does your tool show that your cooling system holds vacuum? It's normal for the hoses to collapse.

It wouldn't pull more than 20in HG but we let it sit and it held there for over a couple minutes. then we drew coolant into the system through the tube

 

[Dodge 1500 4X4]

It wouldn't pull more than 20in HG but we let it sit and it held there for over a couple minutes. then we drew coolant into the system through the tube

Please verify the Radiator is cooling, go to autozone they have a IR Temp gun and have them check to upper radiator temp and the Lower radiator temp if its not at least 50-60 degrees cooler the radiator is clogged.

 

[crash68]

you probably need this coolant system bleed tool..

 

[Lifted92]

I have now done multiple tests and there is no exhaust gasses in the coolant and I have tried bleeding it while on ramps with the filler neck at the highest point and nothing has changed. Tempted to go through and replace EVERYTHING in the cooling system of this damn pickup

 

[GTyankee]

I would first burp the hoses going to the heater, maybe removing the hoses as close to the water pump as you can, maybe tie the ends up above the radiator, then take a water hose & a nozzle & put the nozzle into the return hose & turn on the water valve on to a low pressure, until clear water comes out of the supply line.
Then pinch off the heater hoses with either hose crimps or needle nose vice grips that have tape wrapped around the metal teeth.
Then slip the heater hoses back on & tighten them back up.
That should insure that no air is in those hoses or the heater.

If that does not get rid of the air bubbles, then you have a leak somewhere. In that case i would think about using DYE to find the leak

 

[CorDog009]

I was going to suggest ramps, since that's what I had to do a couple of times, but you already did that. After the second time I could hear air bubbling and gushing around inside the radiator, removed cap and topped it off and mine finally purged all the air out.