Riddle me this

[Aretoo]

My truck puked coolant for the 2nd time today. Yes I am going to replace my cap and check my pressures. Here is the part I find interesting, and why I am posting the question, it only does it when I leave the truck plugged in overnight. At home I have it on a timer for 3 hours before I leave for work. I work a 24 hr shift so before I go to bed for the night I plug it in. The only 2 times it has puked has been when plugged in overnight. I have run it much harder other times without it puking. Any ideas? If the heater somehow causing pressure to build in the coolant system being plugged in that long? Any Ideas??

[04cr450]

good question never seen this before. I dont think that would have anything to do with it but im not a pro.. I would think if it is puking you have issues that dont pertain to a engine block heater.

[F250SixOH]

Hook up a pressure gauge and then plug the truck in for a few hours. See if it builds pressure.

[Aretoo]

Originally Posted by 04cr450

good question never seen this before. I dont think that would have anything to do with it but im not a pro.. I would think if it is puking you have issues that dont pertain to a engine block heater.

That is why I find this so puzzling. I am currently running Matts SRL that is dialed back a little due to excess smoke issues. I have run hotter tunes than this and also run the truck much harder than I did this am without an issue. It has only done it when the truck has been plugged in overnight.

[twoicebergs]

Does it puke overnight or after shutting it off, or does it puke after you ran it the day you plugged it in? What is the ECT after plugging it in? These should be mutually exclusive events, unless your heater can make you coffee. It is probably just coincidence you noticed it on those days.

[Qholic]

Nathan, is the puking after you start the truck and ran it for awhile or while it is plugged in? My thoughts are that if it's after you ran it for awhile and the t-stat opens the hot coolant meets up with the cooler coolant and somehow there is a pressure build up. I know not very scientific but just my 2 cents.

[Aretoo]

Originally Posted by twoicebergs

Does it puke overnight or after shutting it off, or does it puke after you ran it the day you plugged it in? What is the ECT after plugging it in? These should be mutually exclusive events, unless your heater can make you coffee. It is probably just coincidence you noticed it on those days.

I have been checking it after each time I run it to see if there is a pattern. Drove it for a week with no puking after the first time. Drove it to work yesterday checked it at work no puke. Plugged it in last night at 2300, unplugged it this am at 0700. Coolant temp when starting this am was about 115F. Drove it home (20 miles) didn't even run it hard. Checked when I got home and it had puked on the way home.

[twoicebergs]

I guess we will have to wait for the new cap. Although, I wouldn't expect it to puke for such a short, soft drive, even if the cap was bad. It might be a good idea to put a pressure gauge on it right away, with the new cap.

[kinnisoj]

It pukes because it over heats. You leave it plugged in at nite,get it all nice and warmed up and by the time you reach work it has reached higher temps than it would have if you would of left the house with a "cold" motor.

[kinnisoj]

About now your saying no way....but this panned out to be true with my truck.