The thermostat controls hot coolant flow to the radiator so even in frigid temps, your surge tank is not shocked. The thermostat is closed recirculating coolant within the water jackets until it reaches the opening temp where it slowly opens. It is not an on off deal. Plus it takes time for the engine coolant to warm in the jackets anyway. I just sold a 7.3 with 37.000 miles on it and it had the original tank. My other truck with 294.000 miles is on its original tank and has been to -15F and over 110F ambient and has no cracks to speak of.

 

Cant edit but technically the thermostat slowly opens until thermostat opening temp. Just to clarify

 

Resurrecting old thread ... I'm on my second degas bottle with a crack. Anyone find something better or just spend the $38 for another plastic one from Dorman?

 

What was your second one - OEM or Dorman?

 

Dorman has never been known for quality. My original bottle went 275,000 miles and 13 years before the crack actually started leaking. I have about a year and 20k on my new one Oem Ford and no signs of cracks or discoloration.

 

Rat49f6,
I have thought of fabing one from AL in the same shape. I have the pattern laid out on card board, but have not gone any further. I think folks here would pay for someone fabricating these.

 

My second was OEM. I remember thinking I wanted to buy OE so I wouldn't have to worry about it again. Well here I am worrying about it again! Over the years I've seen the crack grow and now I have a slow leak. Need to get that taken care of before our next camping trip.

I might go back with the part and complain to the guys at the parts counter. That and $1 might get me something off of the McD dollar menu but it might be worth a try...

 

1. Do you see a rainbow on top of your coolant?
2. Did you install a new cap?

 

Not sure, don't think so but i'll check next time I'm around the truck (not my daily driver).

Are you thinking oil leak into the coolant / vice versa? I meant that there is a bit of coolant leaking out of the degas bottle out of the crack.

My last UOA showed no coolant in the oil - that was about 1.5yrs ago.

That I don't remember - I think i used the old one, IIRC the bottle doesn't come with a cap.

GC

 

I bought a new cap at the Irish place when I put in the new bottle. I'm thinking one overheat, fuel/oil in coolant, or a bad cap can get you crack on-high.

 

These trucks do have amazing cooling systems. I was 19K GCWR over Stevens Pass last weekend, with my damaged degas bottle (hole near the top) so it could not pressurize. Engine stayed cool and coolant stayed at the level of the hole.

My second Dorman bottle just came from rockauto and I'll be putting it in when I can do the injector cup job, hopefully in a couple of weeks. Until I have faith the coolant will not get contaminated again by fuel (or oil, shoot I'll probably have my oil cooler let go), I'll be buying the lower cost bottles.

After an injector cup job and oil cooler reseal, I'd probably recommend going back to OEM. That bottle does last, and being able to see through it better to judge coolant condition is nice.

 

That saved me a PM. I guess I'll be installing star washers on my injector bolts this weekend (some are still spinning).