Say No to Plastic! Mishimoto's Fiesta ST Coolant Expansion Tank

[mishimoto1]

Time to dive into yet another Fiesta ST project! This little Fiesta is getting the royal treatment at Mishimoto; over the last few months it has been fitted for numerous upgrades. If you are in the mood for a recap you can head over to our Mishimoto Directory thread or the Mishimoto Engineering Blog on our website. For now we?ll dive right into our development of Mishimoto's expansion tank for the Fiesta ST.

Stock Expansion Tank

Here at Mishimoto we feel a certain type of way about plastic. It is not that we have a vendetta against plastic, but we see an area where we can improve upon some of the stock Fiesta ST parts. Plastic expansion tanks in general (or any plastic parts) are more prone to failure than an aluminum part would be. Plastic becomes brittle with age, exposure to elements, and the repeated heat cycles in the engine bay. Replacing the plastic tank with an aluminum one not only looks better, but it also would be less prone to bursting or cracking especially as the Fiesta ages. Check out a couple shots of the stock Fiesta ST expansion tank.

Stock Fiesta expansion tank in engine bay

The stock expansion tank is your run of the mill plastic expansion tank. There are no impressive additions from the factory that we would be required to recreate (as seen on some of our other expansion tank projects). Ford did, however, have an interesting design for the inside of the tank. Lets take a closer look at the inside of the stock Fiesta ST expansion tank.

Stock Fiesta expansion tank

Stock Fiesta expansion tank

Internals of stock Fiesta expansion tank

Internals of stock Fiesta expansion tank

Internals of stock Fiesta expansion tank

Internals of stock Fiesta expansion tank

It?s not all bad! The inside design is intricate, featuring many compartments and grooves to prevent sloshing. We will certainly incorporate this style into our design because we want improved function in addition to form.

3D-Printed Version

After a thorough look inside and out, we took some measurements of the stock unit so we could create a prototype version with our 3D printer. The prototype fit nicely into the space for the stock expansion tank and there were no clearance issues with other Fiesta ST parts in the engine bay. Check out some shots of the 3D-printed version below!

3D printed Fiesta expansion tank installed on the ST

3D printed Fiesta expansion tank installed on the ST

3D printed Fiesta expansion tank installed on the ST

3D printed expansion tank in relation to other Fiesta ST parts

3D printed Fiesta expansion tank installed on the ST

Coming Up!

Now that we have confirmed fitment with our 3D-printed expansion tank for the Fiesta ST, we can move on to create an aluminum version for additional testing. Stay tuned for more on this and other Fiesta ST parts in our next post!

Thanks for Reading!
-Sara

 

[frankiefiesta]

Love this.. Saw your mustang gt coolant tank and was hoping one was going to be made for our cars

 

[Hijinx]

So... What benefit does this have?

 

[frankiefiesta]

So... What benefit does this have?

Engine bay bling ..basically just cleans up the look. Aluminum looks better than clear plastic. They can say the plastic has a chance to fail, crack, explode, whatever lol but chances of that are slim

 

[Hijinx]

Engine bay bling ..basically just cleans up the look. Aluminum looks better than clear plastic. They can say the plastic has a chance to fail, crack, explode, whatever lol but chances of that are slim

That's what I was thinking. Why is it so hard to call a duck a duck?

 

[bodytech]

That's what I was thinking. Why is it so hard to call a duck a duck?

you mean that goose thing

 

[CanadianGuy]

mmmmm more bling.

 

[westcoaST]

Plastics have a tendency to crack, especially if exposed to ethylene glycol that has become acidic. The Fiesta ST tank is no different. Once the tank starts to lose its plasticizer, it yellows and becomes brittle. This is the time it can crack and fail. Usually this happens when you are miles from home, not in your garage. I replaced my 2011 Mustang's tank for the same reason. Plasticizers are additives to plastics to make them more flexible. Over time these compounds leach out of the plastic, and the plastic reverts back to its brittle state.

Oh and it adds more bling to the engine compartment, but I do not think that this is its primary reason for being fabricated by Mishimoto. Its kind of like plastic radiator end caps VS aluminum ones.

 

[mishimoto1]

Love this.. Saw your mustang gt coolant tank and was hoping one was going to be made for our cars

So... What benefit does this have?

Engine bay bling ..basically just cleans up the look. Aluminum looks better than clear plastic. They can say the plastic has a chance to fail, crack, explode, whatever lol but chances of that are slim

That's what I was thinking. Why is it so hard to call a duck a duck?

you mean that goose thing

mmmmm more bling.

Plastics have a tendency to crack, especially if exposed to ethylene glycol that has become acidic. The Fiesta ST tank is no different. Once the tank starts to lose its plasticizer, it yellows and becomes brittle. This is the time it can crack and fail. Usually this happens when you are miles from home, not in your garage. I replaced my 2011 Mustang's tank for the same reason. Plasticizers are additives to plastics to make them more flexible. Over time these compounds leach out of the plastic, and the plastic reverts back to its brittle state.

Oh and it adds more bling to the engine compartment, but I do not think that this is its primary reason for being fabricated by Mishimoto. Its kind of like plastic radiator end caps VS aluminum ones.

Thanks for the kind words guys! Of course this product has more than one benefit, the more obvious being that aluminum looks great! To be more specific, we are not expecting the stock tanks to crack or leak especially on such a new vehicle. They should hold up, even if they are plastic, but further down the line as the car ages failure is certainly a possibility. This expansion tank is more for those who want a cleaner look to their Fiesta with the added benefit of removing a part that could fail in the future. Can we call a penguin a penguin?
-Sara

 

[Young L]

maybe a powered coated version for those of us that arent into the bling bling

 

[westcoaST]

I'm sure the aluminum will either be powder coated or anodized to protect it. My vote is for red, blue, or black anodize. Also, how about rounding the edge near the AC line, so its more like the OEM part?

 

[MyGoKart]

Of course this product has more than one benefit

This expansion tank is more for those who want a cleaner look to their Fiesta with the added benefit of removing a part that could fail in the future.

Wait what?

 

[westcoaST]

Wait what?

Read my post, page 1. Plastic tanks that hold ethylene glycol will eventually crack, then possibly leak, and need to be replaced.

 

[MyGoKart]

Read my post, page 1. Plastic tanks that hold ethylene glycol will eventually crack, then possibly leak, and need to be replaced.

Okey!

Plastics have a tendency to crack, especially if exposed to ethylene glycol that has become acidic. The Fiesta ST tank is no different. Once the tank starts to lose its plasticizer, it yellows and becomes brittle. This is the time it can crack and fail. Usually this happens when you are miles from home, not in your garage. I replaced my 2011 Mustang's tank for the same reason. Plasticizers are additives to plastics to make them more flexible. Over time these compounds leach out of the plastic, and the plastic reverts back to its brittle state.

You never said they eventually crack. You said they have a tendency to crack. And you gave some Elementary school chemistry lesson about how you know more then Ford Engineers.

Besides, I wasn't talking to you. The only advantage to these is that they look cool under the hood. Trying to market them as preventative maintenance is false.

 

[westcoaST]

Okey!



You never said they eventually crack. You said they have a tendency to crack. And you gave some Elementary school chemistry lesson about how you know more then Ford Engineers.

Besides, I wasn't talking to you. The only advantage to these is that they look cool under the hood. Trying to market them as preventative maintenance is false.

I am a Materials and Process engineer. I see you've never heard of plastic overflow containers fracturing after years of use. Just my two cents. Sorry if I offended you.

 

[CanadianGuy]

I agree with [MENTION=411]westcoaST[/MENTION] on his statement but my agreeance is based on personal experience as many of my previous vehicles were well pass there 10 years of age. I saw some plastic brittle, no different than the hoses. They may not crack until they are vibrated or hit by a hand when a wrench slips (ask me how I know). I would than go to a wreker and get more tanks be it windsheild wash, power steering, radiator or brake fluid. I am not saying all my vehicles had that problem but I would say 1/4 of them did various makes and age. Those I liked I was proactive, those I did not JB weld was handy.

 

[MyGoKart]

I am a Materials and Process engineer. I see you've never heard of plastic overflow containers fracturing after years of use. Just my two cents. Sorry if I offended you.

Sweet. I've owned plenty of cars with Plastic overflow containers and had several crack. Quick trip to BMW dealer $35.00 later, New revised design. You're making it sound like every single one out there will eventually fail and that Mishimoto is the god save all. Doesn't sound like the type of logic an Engineer (!!!) would use.

I agree with [MENTION=411]westcoaST[/MENTION] on his statement but my agreeance is based on personal experience as many of my previous vehicles were well pass there 10 years of age. I saw some plastic brittle, no different than the hoses. They may not crack until they are vibrated or hit by a hand when a wrench slips (ask me how I know). I would than go to a wreker and get more tanks be it windsheild wash, power steering, radiator or brake fluid. I am not saying all my vehicles had that problem but I would say 1/4 of them did various makes and age. Those I liked I was proactive, those I did not JB weld was handy.

Point noted, Keep wrenches away from overflow tank 10+ Years from now.

 

[westcoaST]

Sweet. I've owned plenty of cars with Plastic overflow containers and had several crack. Quick trip to BMW dealer $35.00 later, New revised design. You're making it sound like every single one out there will eventually fail and that Mishimoto is the god save all. Doesn't sound like the type of logic an Engineer (!!!) would use.


Point noted, Keep wrenches away from overflow tank 10+ Years from now.

That is why I said they have the tendency to crack in my original post. I think you are reading more into my post than I intended. Sometimes, when the plastic part cracks, the dealer no longer makes or has replacement stock and you are forced to use JB weld or a junk yard. I'm really not trying to make it sound like all of these parts will fail, only that the potential exists for failure, based on the physical properties of most plastics and plasticizers. I really don't think I said Mitsubishi was or is the god save all. Plastics will last for several years in harsh environments, such as the overflow container on the ST. There will be some that fail sooner than others, some that fail later (Bell curve). I'm not promoting any one product line, just providing information, based on over 40 years of experience. I only have one Morimoto part on my FiST, the baffled OCC that I purchased before they decided to make a custom fit one.

 

[MyGoKart]

That is why I said they have the tendency to crack

"Will Eventually Crack". You went so far as to analyze the chemical consistencies of the plastic Ford has used.

I think you are reading more into my post than I intended.

You regulate my Reading?

Sometimes, when the plastic part cracks, the dealer no longer makes or has replacement stock and you are forced to use JB weld or a junk yard.

Sure, for a 1960's MG. - This is a Globally sold 2014+ Car using one of fords most popular Engines.

I'm really not trying to make it sound like all of these parts will fail

That is Exactly what you said earlier. Stop Back Peddling.

only that the potential exists for failure, based on the physical properties of most plastics and plasticizers.

Read this and try not to laugh.

Plastics will last for several years in harsh environments, such as the overflow container on the ST.

That is not what you said. Heck you even threw your Engineering job (!!!) into this mess.

There will be some that fail sooner than others, some that fail later (Bell curve).

Durrrrrrrrr

I'm not promoting any one product line,

And I'm not bashing their parts. But arguing that this solves any kind of problem is a Joke.

 

[dyn085]

And I'm not bashing their parts. But arguing that this solves any kind of problem is a Joke.

^ Exactly this.

On a side-note, will there be a sight glass so that people can see how much couldn't is/isn't in there or will you have to remove the cap every time to check it?