Coolant spraying... What is going on?

[snailexpress]

If you didn't purge air properly it can cause spot overheat in the rear part of the block and head. Drain some coolant and start over to save engine.

[Rawze]

(10-25-2017 )Waterloo Wrote:  Ok, did the overhead, installed new CAC, put everything back together, went to start and I have coolant spraying everywhere! Coming out of the coolant bottle, and somewhere else. I shut it down, thinking WTF! Now what!

When I took the coolant bottle off to replace the CAC, I drained about three gallons of coolant out of the system to drain the bottle. I filled it up after getting everything back together and burped the motor.

I looked all over the motor, pressure tested the cooling system, nada.

Restarted the motor, purring like a kitten, the coolant is keeping its level in the bottle. Sits overnight, and pressure has built up in the system near as I can tell. Could it be something as simple as a bad radiator cap?

Now I start it today, and same thing! Spraying coolant everywhere, after sitting overnight. Restarted and all is fine...

Don't tell me a head gasket.

Thats a typical prostar problem. here is why it acts so strange ...

The heater core in the cab of the truck is at a higher level than the coolant tank. It is quite common when excess amounts air gets into the coolant system, it gets trapped accumulates in the heater core and blows about 1.5 gallon or so of coolant out the cap. Run the truck for a while, and the coolant level will show 1.5 gallons low,. so what does a good truck owner do? -- Fills it back up. -- Then the cycle repeats.

This explains the strange behavior, but leaves only one question.... Where is the air coming from that is building up?


Well, since it happened all of the sudden after draining the system and then putting back the coolant...

* Did every single drop you took out go right back in when you filled it up? -- If not, then there was an air pocket and that is a really bad thing on a wet liner engine. I have seen my share of engines destroyed by people not burping the system correctly. Personally, I use a vacuum pump and fill the coolant system from the BOTTOM OF THE RADIATOR after pulling a full vacuum on the entire coolant system. When you do this, every single last drop of coolant goes back into the system and there is no possibility of an air pocket.

If you have an APU, the problem is much worse and all the air from the APU and lines can damage an engine 20 minutes down the road after you think you have it all back in.


My suggestion,... drain about 3-4 gallons then pull a full vacuum on the system. Make sure the vacuum holds, and it is not sucking air from the compressor, turbo, or some place else. I have even seen them suck air at the thermostat housing gasket under vacuum when helping others here in the past. Pulling a full vacuum on the coolant system should be standard procedure if you ask me.

After pulling a vacuum, fill the system back up from the BOTTOM drain plug (without letting air in) or pour a gallon in then pull as much vacuum as you can, pour more in, pull vacuum again, and keep doing that until it is topped off.

Run the engine with the cap off until it gets to 185-F and stays there for a good 5 + minutes (total run time about 25-30 minutes). Make sure it does not need more coolant.

After purging all the air, ensuring its topped off, and everything is right,.. put the cap on and test drive it. If it happens again, you have a serious issue that was most likely caused by not burping the system properly the first time.

[Rawze]

(10-25-2017 )Waterloo Wrote:  ...
I took the coolant bottle off to replace the CAC
...

Its too late now,.. but ....There was no need to drain the coolant at all to replace the CAC in the prostar. You should have just disconnected the bottle at the mounts and let it hang.

[Waterloo]

(10-25-2017 )snailexpress Wrote:  

(10-25-2017 )Waterloo Wrote:  I have not tried with the cap off. I start the motor cold, cap on, she sprays, I shut her down, and immediately restart, no issue on the restart with cap on or off. The system itself does not seem to be building any pressure other than what would normally expect, a bit of water cavataion in the bottle. I put my hand over the coolant jug top for a few minutes, I felt no pressure on the palm of my bare hand at all.

You didn't read Cummins coolant fill instruction.
What it says -
Close the bleed valve on the upper radiator pipe, or install the
pipe plug. Do *not* install the coolant pressure cap at this time
* Start the engine and allow it to reach an operating temperature of
85°C [185°F], or until the thermostats opens.
* Shut the engine off and check the coolant level. Adjust the coolant
level, as necessary.

If any drained coolant remains after filling, there is an air pocket in
the system which *must* be purged. Allow the engine to reach operating
temperature and top-off the system with coolant.


NOTE: Proper fill and deareration of the system is critical to
EGR cooler life.

Yep, that is how I do it. And I have the petcock at the top crossover pipe from the Thermostat.

[Waterloo]

Yep, heater core... All makes sense now. Thanks Rawze, I will pull a vacuum on the system, I have the tools... And I have not driven the truck yet, she is not leaving the driveway until this is fixed. I tell ya, it does not take much to upset these trucks.

And you are correct, not all of the coolant went back in. Dumb ass mistake on my part, I should have figured this out by myself. But, that is how we learn and the reason for this site. ;-)

[Rawze]

(10-26-2017 )Waterloo Wrote:  Yep, heater core... All makes sense now. Thanks Rawze, I will pull a vacuum on the system, I have the tools... And I have not driven the truck yet, she is not leaving the driveway until this is fixed. I tell ya, it does not take much to upset these trucks.

And you are correct, not all of the coolant went back in. Dumb ass mistake on my part, I should have figured this out by myself. But, that is how we learn and the reason for this site. ;-)

I have even seen where repair shops make that mistake and kill someones engine.

Worse case scenario, you can drive it somewhere if need be with the cap loose + a rag zip-tied over the neck to hold cap in place after it pukes out some coolant and the system settles. That is, as long as it shows a few inches or more above the bottom of the bottle.

[Waterloo]

(10-26-2017 )Rawze Wrote:  

(10-26-2017 )Waterloo Wrote:  Yep, heater core... All makes sense now. Thanks Rawze, I will pull a vacuum on the system, I have the tools... And I have not driven the truck yet, she is not leaving the driveway until this is fixed. I tell ya, it does not take much to upset these trucks.

And you are correct, not all of the coolant went back in. Dumb ass mistake on my part, I should have figured this out by myself. But, that is how we learn and the reason for this site. ;-)

I have even seen where repair shops make that mistake and kill someones engine.

Worse case scenario, you can drive it somewhere if need be with the cap loose + a rag zip-tied over the neck to hold cap in place after it pukes out some coolant and the system settles. That is, as long as it shows a few inches or more above the bottom of the bottle.

I thought of that, driving without the cap, but figured it would be something simple and wait to hear from Rawze.com. Besides, everyone is 5 or 6 weeks out on appointments. I have the AirLift to pull a vacuum, just need a fitting for the radiator to fill from the bottom, I'll find what I need at Home Depot or the local ACE Hardware. I figure I will just change out the coolant and get her ready for winter. That old TriPac (2007 Model) of mine is a continual source of coolant loss, and I have a mishmash different coolant brands in the system over the past few months. The new TriPac is waiting for me at the ThermoKing Dealer, they can't fit me in until Dec 18th for the install. Lack of mechanics, can you believe that? LOL!

I'm about ready to quit trucking and go to mechanican school, seems like I do that as much or if not more than drive.

[yamajason]

(10-26-2017 )Waterloo Wrote:  ...

How is the mechanican school of Rawze coming along? How did that AirLift kit work out for you? Learn any new tricks for filling/purging coolant system?

I found this thread while researching ways to Prime a Diesel Engine that does not have a Priming Pump/Lift Pump. I remember helping a guy at the truckstop that ran out of diesel and the mobile service guy had a vacuum pump like
https://youtu.be/SGIRz7cf9SM

I would like to find a vacuum pump that would work for Coolant Pulling and Fuel Priming.