Looking at Rudy's degas bottle from the side... no pitch angle, smaller sight glass.





Now that Rudy's Diesel is a reseller of Mishimoto products, is the Rudy's degas bottle even available from Rudy's anymore? The photo above was from eBay, on a sold out listing.

Perhaps Rudy's is no longer importing / reselling their own branded bottle anymore, and resells Mishimoto instead?


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I would be more inclined to buy Sinister Diesel products if they didn't engrave their name and logo all over them. It appears as if their bright blue bling can be avoided at least on the degas bottle (but not on the coolant filter head).

The aftermarket engraving is a point of pride for both the vendor as well as many buyers, who like to display the bucks they've blown under the hood.

But unless the vendor has a CARB E.O. # for the product, their laser etched name serves as a homing beacon for a bureaucratic witch hunt.

 

That looks very similar to the Mishimoto unit, however for the price that could be a winner assuming it fits correctly.

https://www.ebay.com/itm/Rudys-Silve...-/173649943697

 

They make a grey one also but I don't mind a little color and bling under the hood.

 

Like CAC couplers, some consideration might be given to material properties of afternarket aluminum degas bottles.

Of interest is how the degas bottle is subjected to fatigue cycles. The degas bottle is essentially a pressure vessel subjected to both thermal and pressure cycling, as well as vibration and racking when rumbling over rough terrain.

Most vendors of aftermarket aluminum degas bottles advertise that theirs are made of 6061, with the exception of one, who states that their bottle is made from 5052.

6061 has a higher yield strength, is harder to bend, easier to machine, and is more thermally conductive, dissipating more heat.

5052 has a higher fatigue strength (96.5 MPa 6061 versus 117 MPa 5052, calculated using 500,000,000 deflections below the yield strength) which means 5052 is more elastic, more tolerant of fatigue cycling, and not as brittle or likely to crack. It is also easier to weld, and therefore more likely to not have weld defects.

Aluminum pressure vessels are more typically made of 5052.

New Ford trucks are made of 6061.

I'd still prefer a clear bottle, but if I had to choose between the two alloys in a degas bottle application, I'd be inclined to go with 5052, due to the degas bottle being an "expansion" tank, subject to dimensional changes from thermal and pressure cycling.

 

This must be the reason i couldn't find it on Rudys website, they must have discontinued them. That's to bad , it seemed like a good product, at a reasonable price, but I do not know what grade aluminum it is

 

Just got confirmation from Rudy's that their unit is no longer being made. Recommended the Mishimoto unit which they do carry at $289. The PSP is a beautiful unit but $389 is show truck only money!

 

There is supposedly another one offered by Rhino Diesel Product that is supposed to be of good quality but at a cheaper price but I haven't found what that price is and how to contact the individual other than on Twitter or something like that. I heard it mentioned on this video about the guy talking about the Mishimoto one he just purchased. He mentions the other option. I'd be curious to find out more about it.....

 

I've got one of Rudy's units which is waiting for me to clear the garage out so I can do both the degas bottle and the IH water pump at the same time.

 

Adding more follow up in comparing features and functions of aftermarket aluminum degas coolant reservoirs:

PSPDiesel degas bottle:

• 5052 aluminum, which I consider a plus for fatigue cycling, formability (bending without fracturing), weldability (less likely to have weld defects)
• Made in USA in Connecticut by Moroso, under an exclusive private label agreement with PSPDiesel. This is a HUGE plus. Moroso has been in business for 52 years. (This product ONLY available through PSPDiesel)
• No longer has PSPDiesel emblem tig welded as a separate tag to the top, Instead the logo is laser etched directly on the top. (neutral to negative)
• (Either way, the logo is a negative, but laser etching directly to the top can conceivably create weak spots, depending on depth of etching, thickness of material, and pressure cycle exposure)
• Has tiered top, with a high point for "degassing" and expansion, as opposed to a flat top. (a plus)
• Has a vertical pitch that matches the factory angled pitch of the stock bottle (a plus that none of the other aluminum tanks have, which are all just straight up and down)
• Has a stiffening gusset on the mounting foot (a plus that none of the other aluminum tanks have, although the need for the gusset with an aluminum foot has not been established)
• Does not have any internal baffle. (a BIG negative, and the no-go deal breaker for me). The OEM tank (and even the Dorman tank) are baffled internally for reasons.

Sinister Diesel

• Made in USA, in California. This is a big plus.
• Internal baffle(s). Another plus.
• 6061 material (neutral to negative theoretically, but may be entirely immaterial in field performance )
• Aluminum corrodes. Powder coating mitigates this. Their powder coating is bright blue. (a plus for some, a turn off for others)
• Has sloped top, with an upper chamber significantly higher than cap. A plus, combined with the baffle, to maintain an air space at the top of tank
• Still investigating as of this writing

Mishimoto

• Flat top design from a single wrap over, rather than a 3 tiered top
• This top design results in a lower gas ceiling space than what Ford originally designed
• Using the upper mounting tab as a reference point, the distance from said tab to topmost part of tank is lower in Mishimoto than any other tank
• The ramifications of this notable deviation from Ford's degas bottle design are still being investigated, but will likely not result in an answer without testing
• The Mishimoto tank is internally baffled
• Mishimoto's Wrinkle Black finish is the most visually attractive and non-chalant when clean, but stains readily with white cloudy streaks from hot coolant (as seen in YouTube video)

 

I have a hard time thinking of supporting a company (Sinister) that copyrighted the color “blue” for truck parts......

Ive been reading this thread but hoping I never need it’s advice. Knock on wood.

Figured I would throw a few links in here to the parts in discussion. It seems the Mishimoto is currently the cheapest of these options at around $290. These should be listed in the order of price.

Mishimoto
https://www.mishimoto.com/ford-power...egas-tank.html
Mishimoto at Riffraff
https://www.riffraffdiesel.com/mishi...le-7-3l-99-03/

Sinister gray
https://sinisterdiesel.com/i-2408818...7-3l-gray.html

PSP
https://pspmotorsports.com/i-3050539...oir-99-03.html

 

(Additional notes have since been added in the preliminary aftermarket degas bottle feature comparison posted earlier above.)

As of this writing, even while undaunted by the high price of these three options, I am not convinced that any of them match the physical characteristics that Ford incorporated into the factory degas bottle. The 3 most prominent physical characteristics are:

1. The ultimate gas chamber height above the upper radiator tank, the road side nipple, and established water level line
2. The internal baffling dividing the degas bottle into flow and slosh controlled chambers
3. The angular canting forward of the lower portion of the tank away from the FEAD. (Front Engine Accessory Drive)

Therefore, I will most likely purchase and pressure test a Motorcraft / Ford degas bottle. At least I won't burn my hands on hot metal.

If the Moroso made, PSPDiesel branded degas bottle was internally baffled, AND, rather than just a sight glass, instead had a site TUBE (like other Moroso made degas bottles, similar to the generic cylindrical degas bottles that PSPDiesel used to have Moroso make for Fummins retrofits), then I would have bought the PSPDiesel tank. I even offered to pay extra on top of the full retail price of the tank to have the site tube added by Moroso at time of manufacture (before I came to realize that the PSP tank had no baffling inside). No dice. I made the same offer to Sinister. No dice. No custom work.

The obvious fact here is that one could buy several OEM degas bottles, and about a dozen Dorman degas bottles, for the price of one of these aluminum tanks, especially the tank that I might have selected, if it had all the physical characteristics I observed in the factory tank, and would like to have in any tank. Since appearance is not one of the requirements to fulfill in my application, and since I apparently cannot throw enough money at the vendors to become a custom customer, replacing plastic appears to be the best option for me. Thanks to the OP for inspiring this probe into the aftermarket options available.

 

I sold the truck a year or so ago but loved the Degas bottle. It did develop a leak in a weld and was replaced with no questions asked. I will be ordering one for my new 6.7 when the tax returns come in.

 

I tried the Dorman and the threads for the cap would not seal, tried 2 new caps...ordered an oem from riffraff no problems.

 

I ordered a brand new one from Clay about a year ago when I was doing the big overhaul. That OEM bottle lasted maybe 2 months before the seam split. Clay refunded it no questions asked. I went the Mishimoto route and have been happy with its performance. Been on for about a year now. I do wish they offered a bigger window into the health of the coolant but I'm happy to report that my Blackstone results found no coolant in the oil. So for now I will roll the Mishimoto. I do have the original bottle on the shelf just in case, along with the OEM alternator and starter.