FL5 Civic Type R Coolant Expansion Tanks: Best Options & Buyer’s Guide

[SBX Performance]

I got bored and put together a quick blog on coolant expansion tanks for the FL5 Type R after seeing way too many OEM plastic tanks cracking, leaking, or just looking terrible under the hood.

It’s not a hype piece — I break down:

• Why the factory tank fails
• When upgrading actually makes sense (and when it doesn’t)
• The real differences between PRL, MDR, AIRTEC, Wunderladen, etc.
• What matters for street vs track vs future big-turbo plans

If you’re planning to keep your FL5 long term or drive it the way Honda intended, this is one of those “boring but smart” mods that’s worth understanding before something fails.


Link’s here if you want to check it out
FL5 Civic Type R Coolant Expansion Tanks: Best Options & Buyer’s Guide – SBX Performance


Curious what setups you guys are running and if anyone’s already had an OEM tank let go.

Sponsored

 

[timestamped]

I got Mishimoto’s red for $265 back in April ‘24, it’s gone up in price since then. It comes with the hose fittings welded to the tank and a 1.3 bar cap, if you want to count those as features.

Mishi doesn’t post the capacity, so I’ve asked them if they can measure to verify as I didn’t before installing, but the PRL is really similar in size and shape so I wonder. Installed PRL tank on a friend’s and it’s a nice piece.

 

[turbolag]

prl has a nice sight glass to easily check coolant level. I think mishi has one too. Not sure if radium has a sight glass though.

 

[Nikw91]

PRL as well.

 

[timestamped]

Scott @Mishimoto gave me this response:

We have not tested the capacity, but it is roughly the same as the OEM. Please note that changing the capacity may affect the pressure. This product is designed to work with the Type R motor while maintaining stock fitment and performance.

I wasn’t exactly satisfied with response, and asked them to measure and verify their tank’s capacity.

The stock cap is 127 kPa (1.27 bar), and the Mishimoto cap is 19psi or 131 kPa (1.31 bar).

 

[getRIGHT]

Great write up as always.
I went with the Origin Fab. No regrets

 

[SBX Performance]

I got Mishimoto’s red for $265 back in April ‘24, it’s gone up in price since then. It comes with the hose fittings welded to the tank and a 1.3 bar cap, if you want to count those as features.

Mishi doesn’t post the capacity, so I’ve asked them if they can measure to verify as I didn’t before installing, but the PRL is really similar in size and shape so I wonder. Installed PRL tank on a friend’s and it’s a nice piece.

I also bought a Mishimoto but ended up using MDR instead. I am glad you asked questions to companies this is what needs to happen more and its sad they designed and "built something" but do not know the ins and outs of what they made. For a good company thats sad. Overall Mishimoto is good especially cause it does not have a huge LOGO on it thats why I like it. Please share the answer if they get it for you

 

[SBX Performance]

PRL as well.

Over and over PRL puts out great products that litereally nobody has an issue with! Its def the safe play and looks good and I like the design for sure

 

[SBX Performance]

Great write up as always.
I went with the Origin Fab. No regrets

View attachment 267696

Thank you I am trying to post what people dont talk about much lol Origin Fab is sexy AF LOL can't go wrong with that one for sure great quality too

 

[Nikw91]

Speaking of coolant tanks, anyone changing their radiator caps on the coolant tanks to 1.3? anything to worry about?

 

[apl360]

I got bored and put together a quick blog on coolant expansion tanks for the FL5 Type R after seeing way too many OEM plastic tanks cracking, leaking, or just looking terrible under the hood.

It’s not a hype piece — I break down:

• Why the factory tank fails
• When upgrading actually makes sense (and when it doesn’t)
• The real differences between PRL, MDR, AIRTEC, Wunderladen, etc.
• What matters for street vs track vs future big-turbo plans

If you’re planning to keep your FL5 long term or drive it the way Honda intended, this is one of those “boring but smart” mods that’s worth understanding before something fails.


Link’s here if you want to check it out
FL5 Civic Type R Coolant Expansion Tanks: Best Options & Buyer’s Guide – SBX Performance


Curious what setups you guys are running and if anyone’s already had an OEM tank let go.

Great info thnx

 

[SBX Performance]

Speaking of coolant tanks, anyone changing their radiator caps on the coolant tanks to 1.3? anything to worry about?

Speaking of coolant tanks, anyone changing their radiator caps on the coolant tanks to 1.3? anything to worry about?

1.3 bar cap is fine only if you’re running an aluminum expansion tank and not the oem one or if the car sees hard driving and the cooling system is healthy and properly bled. I would upgrade the hoses too

I actually just ordered a 1.4 cause I have the supporting mods. I could have went 1.3 but I wanted to try it shouldnt be a big deal I have upgraded radiator, hoses, turbo and cooling system

I have COBB radiator hoses in stock if anyone is interested in the upgrade

 

[jedi03]

I got the wunderladen as I like the larger sight glass an the design. Got mine in raw as it was the only available option wjem I orderred. Only have 4k miles on my ITS so far but will swap it out when the stock one fails

 

[SBX Performance]

I got the wunderladen as I like the larger sight glass an the design. Got mine in raw as it was the only available option wjem I orderred. Only have 4k miles on my ITS so far but will swap it out when the stock one fails

Nice that one seems very durable and the sight glass looks good for sure. These OEM ones don’t last long for most people lol keep me updated when you try out Wunderland

 

[k20.dennis]

Definitely digging the Airtec tank.. lesser known brand but it’s a high quality unit!!