Anyone installed the MillerCat shield on their Prius 5th gen?

Yes. Miller includes window stickers with the sale of their shields.

I don't think it would hurt to have them on but imho, I don't necessarily think they'll help either. I've seen a lot of videos of thieves quickly approaching cars, jacking them up, and either chopping away or immediately dropping the car back down and moving on. The one's that I've seen aren't the smartest people around and are in a hurry. That's why I say that having anything to block them is a good thing and hopefully they'll move on rather than take the time to make more noise.

As for the painting of them, I don't trust the recyclers either. I believe all they need is a name to register to their purchase who they can then say "they affirmed the trunks of cats were not stolen". To put it simply, I don't believe the ones who cut them off in the middle of the night are the only crooks in this game.

 

I installed these cheap 5/8 inch spring tension hose clamps on the hexes of the mounting bolts, so the thief not knowing that they are there or having long reach pliers are slowed down or stopped.



By that time, they might have cut the back pipe of the cat and the wire of the oxygen sensor, but you might still have the cat and a less expensive repair, especially in a CARB state that requires a replacement equal or better than OEM quality.

 

Unless you had a video camera on your car or a cat stolen, you may never know that a thief had cased your vehicle. A cat shield, painting the cat, or the stickers might prevent a thief.

 

Cat Security™ Unveils Cutting-edge Bi-metal Shield for Gen 5 Toyota Prius | Torque News

 

Just talked to our Toyota dealer and they say that doing so would go against our car body warranty. He said don't do it. Prius 2023 are so low to the ground, he said, it would be hard to get the cat stolen anyway.

 

Interesting. My dealership put in writing that it won’t affect warranty but only with the Miller cat shield because Toyota sells it as a part. I’m still not sure I’m going to do it. I don’t think it matters how close it is to the ground. They jack them up so easily. I think the thieves aren’t focusing on the 2023. Not enough on the road yet. Gen 2 is most profitable.

 

Toyota sells the shield as an option so it isn’t changing warranty. I am not satisfied with the shields sold. Carbide toothed saws cut through most everything except hardened steel or carbide. The shields are easy to cut, even though it goes against the grain to say that. There is nothing drastic there. They even have vent holes to start the cutting in. The thieves just need a little more experience. It’s a shame really there are people like that.

 

Is it worth the extra cost to get the SS version instead of Al, if the main function is to indicate to the would-be thief that this car will take more time to harvest?

 

Good question. With our Gen 3, I had about 6 foot of chain laying around, so I wrapped it round the recessed cut zone, with nuts/bolts securing it at every wrap, and permanent thread-lock on the outermost bolts. Plus engraved VIN. Cost me nothing, but hopefully acts as deterrent, tip would-be thief to move on.

 

This sounds like a great idea. Wish I had someone like you near by. : }

 

You can use promo code "azusa" and save at millercat.com

 

Hey there, I bought a 90 dollar one on eBay, did it myself, and it took around 30 minutes, hardest part being lifting the entire car lol. All you need is either a rachet or a drive with some loctite. Cheers and good luck!

 

Resurrecting this thread for (hopefully) a couple quick questions to those that have DIY’d their cat shield:

I’ll be installing (DIY) the MillerCat PTN59-47231 shield (stainless) soon once it arrives. I’m not huge/super barrel chested, but I’m big with a large chest/rib cage, some oil/filter change 'issues' even with my Chevy Silverado on ramps. I’ve seen this video 2024 Toyota Prius LE 5th Generation Catalytic Converter Cat Shield Install , looks straightforward but I don’t really like his car lift procedure (the 1 x 3T jackstand on driver front side, 3:11 and 4:13 in the video).

To give me “adequate” working room (however many inches that turns out to be), I’m planning on using my plastic ramps, then raising the car via front lift point (the one that’s pretty far back from front facia) with my low profile 3T floor jack and then putting 2 x 3T double lock jack stands (11.25” low, 16.75” high) on front driver/passenger sides.

1. For those that have DIY’d their cat shield, roughly how high did you need to raise the front of your Prius to gain adequate working room in your situation?

2. After you installed it and drove some – any rattles? If so, anything you’d do different on the install to prevent rattles?

 

I put in a MillerCat d.i.y. and l am not big myself, just average. I used ramps, then a special very heavy duty 4x4 scissor jack on the front center lift point to lift the car even more, and then l used two jack stands (one on each side) on the front pinch welds to secure the car (plus chocks on the rear wheels with parking brake set). Did not measure how high l got it, but l would suggest you lift the car as high as you possibly can without compromising your safety of course. Lifting the front is what matters. The problem for me was not getting under the car after jacking, my problem was more having enough space for my arms to grab wrenches and such. So get all of the safe height that you can.

No rattles or problems after installation. Followed the directions except l used feel to tighten the security bolts on the 2 aft located cross braces, as there was no way l could get a torque wrench with the security bit on those bolts.

I too ordered a SS millercat, but it is big, flat, and very heavy, so l exchanged it for an aluminum one (also big and flat, but considerably lighter), just to reduce curb weight. I also painted most of the shield orange, so that it will be very obvious to thieves that a shield is installed. I also took the two decals included and stuck them, not to the body or windows, but under the car (one on each side), kind of at a near vertical angle on one if the plastic underbody covers, so the stickers will be very visible to any thief looking under the car, or attempting to jack the car from the sides.

 

Many thanks on this. Kind of confirmed what I thought – after looking at that ’24 LE cat shield install video, I thought, there’s no way I’m gonna be able to work like that (only 1 jack stand), I need more work room.

Hoping my 3T floor jack at the front lift point can get things high enough for enough safe height with the 2 x 3T jack stands at the pinch welds, we’ll see.

Good to hear on lack of rattles, guess Motor Trend experience (‘after six months and about 8,000 miles of driving, we haven’t noticed any difference in performance. No change in quietness, no rattles, no discernable shift in acceleration or heat”) was valid We Test a Catalytic Converter Shield, the Toyota Prius Upgrade You Never Want to Use .

Received the cat shield yesterday. Like you, my torque wrench probably too big for those aft security bolts, either than or spring for a smaller wrench. I’ll also have to get some proper (more form-fitting) work gloves, my yard gloves too bulky for handling the SS shield, it does have sharp edges. Good minds think alike, am also planning on affixing the warning stickers low vs. on the windows. Not planning on HT paint for the shield but a good idea.

On a (somewhat) related topic – in this thread some have mentioned concern for gasoline particulate filter (GPF) protection. My understanding is that US (and Canada?) models don’t have GPF’s on the 2.0 liter M20A-FXS - is this wrong?. Europe/other countries Prius models a different story, but no GPF (yet) for the Gen 5. Nothing in US owners manual about regen warning/procedure, the VECI under hood sticker has no GPF notation. In the US, I thought that if a vehicle has a GPF it has to be indicated on the VECI, had to be described in EPA/CARB compliance info from the manufacturer.

My ’26 VECI notes DFI (direct fuel injection) + SFI (sequential multipoint – electronic – fuel injection), and EGR (exhaust gas recirculation), and EGRC (EGR cooler), and WR-HO2S(2) (2 x wide range/linear/air-fuel ratio heated oxygen sensors), and TWC(2) (2 x three-way catalysts) – but no GPF.

Toyota’s EPA/CARB Application for Certification 2026 Model Year (for both Prius and Prius PHEV), and CARB Executive Order approvals don’t mention GPF anywhere. Engine Control System Schematic (page 64 for Prius HEV Microsoft Word - FOI_TTYXV02.0H3B_APP_INI_R00(残りバッテリーラベルのみ), page 93 for PHEV Microsoft Word - FOI_TTYXV02.0H3W_APP_INI_R00) don’t show a GPF. Same for the US ’26 Corolla Cross Hybrid with the M20A-FXS.

Anyway, will see how the MillerCat install goes tomorrow.