I plan to add oil catch can and do maintenance on my car

Ses Mendel signature . He's a guy from Canada right here on this list and down in his signature are the instructions for all of these things you want to do in step by step probably with photographs and all of that You can set the phone right next to your project and go right to town without any issues parts all of it there are sections here on various catch cans there's not really much to them there's no special technology and catch cans to be real honest about it there are a few places that people put them all contained here on this site I would hate to think somebody would have to type all this out again but there is years of this here.

 

If you want to break it up, maybe start with the intake manifold cleaning; it's the final leg of the EGR. You need to unbolt and lift off the throttle body for this, but it's not necessary to disconnect it's coolant hoses*; they have enough slack that you can shift the throttle body out of the way and tie to the conduits on the side of the inverter.While the intake manifold is off is a good opportunity to clean or replace the pcv valve; it's right there on the block sidewall, mounted sideways on a bolted plaque about the size of your hand.

Do clean the throttle body, using carb cleaner, while it's off.

Then another day you can pull off the wipers and cowl, address the EGR valve and cooler. Coolant hoses* do need to be disconnected from the cooler, but if first drain 2 quarts of coolant from the radiator (into a clean container), the coolant level in the system drops low enough that the cooler will be dry (apart from maybe a few tablespoons trapped).

It's good strategy to do some preliminary stuff when doing the EGR valve/cooler: the lower cooler bracket nut/stud is hard to get to, will slow you down if you leave it till during the main job. Just take it off in advance, both the nut and stud (the latter needs an E8 socket), and leave them off. Everything will be fine without it.

I found backing out the (EGR cooler lower bracket) stud particularly difficult, just due to all the conduits and brackets in the way. I ended up using a compact 1/4" ratchet with E8 socket, so tight I could only do one click at a time. And due to disimilar metals it was hard-turning all the way out.

I would also preemptively remove, lube and reinstall the upper cooler bracket bolt, and the nut/stud combo going through the EGR valve.

Note: with the EGR cooler lower bracket stud/nut removed, you no longer need to remove the rearmost studs, the ones at exhaust manifold connection. This saves additional hassle, and with those studs still on the gasket will be retained, less prone to drop and get lost.

Depending on your mechanical competency, you might want to leave the oil catch can for another time. It took me ages, mainly to get my install dialed in. I would never have gotten through it if I'd done at same time as EGR cleaning. Maybe just do the EGR first, get it complete. rest up, research Oil Catch Cans, install locations, hoses and so on, and just resign yourself to doing a second intake manifold removal for that.

Hands down the most efficient hose connection technique is @danlatu's, in the OCC thread linked in my top signature link. He cuts the PCV hose (between PCV valve and intake manifold, at the middle, pushes on 3/8" brass barb (or Pex) splicers, and 3/8" ID fuel line (SAE30R7 is good, available at most auto parts stores, by the foot). From what I've read, clamps are not necessary with barb splice connections, can actually be detrimental to hose end condition over time.

There are cheap as dirt OCC's, and crazy expensive ones. I went with Moroso 85474, but they're pricey. One gotcha with them: there's large O-ring between it's two halves, very fragile; manufacturer recommends to relube with anti-seize each time it's apart. They did supply me with the spec for the O-ring, and I was able to source a bunch of replacments, cheap.

Where you mount the OCC is an interesting journey. I went with a L-bracket loosely** mounted atop the lower cross-beam, below the intake manifold, and the oil catch can bolted to that. A lot just tuck in the corner at the top, just beside the drivers-side headlight.

Torque values, tools required list, video links, repair manual excerpts, cleaning tips and so on, are in top two links in my signature. (on a phone turn it landscape to see signatures)

* If you're doing a coolant change at the same time, then you don't need to worry about spillage, just drain the coolant first.

** That lower cross beam is the front jacking point on gen 3; it needs to flex, and anything solidly bolted to it will cause stresses, in both the bracket and beam. To alleviate that I put a rubber gasket between the bracket and the beam, and used finger-tight bolted connection.

 

After having done the EGR the first time just a few months ago, I'll second Mendel's * point of doing the coolant change at the same time. There's a bunch of coolant/vent lines running around there and draining the coolant first just makes it easier. That way you don't have to bother clamping off the coolant lines and spilling (much) coolant.

I'm also thinking that maybe a little oil in the intake isn't such a bad thing. I know it runs contrary to the popular consensus, and there's definitely a point where it becomes a problem. If you're cleaning the EGR system and throttle body every 70K miles, it shouldn't be building up to a point where it becomes a problem. I didn't do my first EGR service on my 2011 till 2024, where it had 120K, and there was only about 1/16 to 1/8 inch of oil in the bottom of the dip in the intake manifold. I'm sure the oil vapors helped stick the exhaust particles to the intake passages, but not really that much. Every car since about 1960 has a PCV system.

I keep thinking about the early cars and their oil bath air cleaner systems. Instead of running air filters like cars since the 1950's, these early air filters trapped contaminants in a pool of oil


Yeah, it's messy and disgusting. It's not like there aren't messy things under that hood anyway. It can also trap things that make it through your air filter that you don't want in your engine too.

 

Don't think my links have info on the pcv valve. Attached is repair manual excerpt.

FWIW, I used LOCTITE 243 Threadlocker Blue thread on the PCV valve threads (in lieu of Toyota genuine adhesive 1324, three bond 1324 or equivalent). You "can" use nothing I think, but you may get some oil-bloom around the connection.

Torque value is 15 ft/lb. Socket size I forget, maybe 21 mm?

@NutzAboutBolts video #15 here:

Nutz About Bolts Prius Maintenance Videos | PriusChat

Covers accessing and changing the PCV valve without intake manifold removal. I believe he mentions socket size.