OK so since I've been a bit OCD with my coolant level I've been checking it constantly since I changed the tstat and added coolant. Since then I have drained some and added some. Had a bit of puke so I drained a bit and got it to a little below the min mark. Added a bit more to get it to the min mark. Drove today and stopped by a friend's house and popped the hood. No puke but heard the cap releasing some air (at least that's where I think it was coming from) My question is this hiss normal?

2006 F350 4X4

 

You may have a weak cap normal vent pressure is 16 psi. Sometimes the cap neck gets a hair line crack.

 

Coolant expands about 6% when hot, so a warm reading will be wrong. Since system capacity is about 7 gallons, you'll be way off if you check it warm (54 ounces wrong!). You should probably get a new cap, check and fill/drain as necessary COLD, and check it COLD at the next two thermal cycles, and then if it's still having issues, pursue it further. Until then, you might be chasing nonexistent problems.

 

this is the updated degus cap for around 10bucks it can be had
6.0 Degas Bottle Cap (Updated Part)

 

I did put a new one on back in the spring but have had it on and off alot here lately. Probably need to smooth the surface and get a new one again. Tks for the link. Alot cheaper than my dealer

2006 F350 4X4

 

Joke answer first.
You must of put some snake oil in the cooling system
and forgot to remove the snake from it first. It wants OUT!

Now the real answer. Could be the A/C compressor bleeding down.
A/C system will run anytime the defrosters are on and it does
HISS when you turn the engine off. Take the cap in and have
then pressure test it.


Sean

 

Dang snakes!!
I'll look at doing that. Thanks

2006 F350 4X4

 

Well the hiss was from a bad degas cap. I pulled my egr to clean and check for wetness. Intake is dry as a desert. A ton of carbon below the egr valve but thats it. I bought a cap earlier in the year to replace the one that was on it when I bought it due to it puking from the dealer overfilling. Well when I changed the tstat I overfilled a bit and got puke. I picked up another new cap friday and put it on today. I could tell immediately that the old cap was bad as the new one took alot more effort to click. I had read in a old thread about a tsb (I think) in which they mention if you get puke the cap is done. Well I can say that is true myself now.

2006 F350 4X4