99 1500 4.8 oil separator options

Amp Wrangler · Feb 25, 2026

I'm getting ready to purchase an oil catch can for preventative maintenance and wanted to check with the experts here to see which brand or type you would recommend.

Appreciate your advice and feedback!

INW-Iron-Steel · Feb 26, 2026

Amp Wrangler said:
I'm getting ready to purchase an oil catch can for preventative maintenance and wanted to check with the experts here to see which brand or type you would recommend.

Appreciate your advice and feedback!

Is this on a stock application or turbo/FI? On a turbo application I would definitely consider a catch can if retaining PCV. On a stock or mild NA build I would not consider a catch can necessary. Are you trying to solve an oil consumption problem? I know early LS applications suffered from excessive oil consumption and oil in the intake. The culprit was said to be the PCV valve. GM released an updated one, the "fixed orifice" valve. After that the PCV was integrated into the valve cover.

INW-Iron-Steel · Feb 26, 2026

Here is the fixed orifice valve. It is quite literally a hollow shell with a small hole drilled in the base

Amp Wrangler · Feb 26, 2026

INW-Iron-Steel said:
Is this on a stock application or turbo/FI? On a turbo application I would definitely consider a catch can if retaining PCV. On a stock or mild NA build I would not consider a catch can necessary. Are you trying to solve an oil consumption problem? I know early LS applications suffered from excessive oil consumption and oil in the intake. The culprit was said to be the PCV valve. GM released an updated one, the "fixed orifice" valve. After that the PCV was integrated into the valve cover.

It currently is 100% stock with extremely low miles. Just considering for preventative maintenance.

INW-Iron-Steel · Feb 26, 2026

I would pull the PCV valve on the back of your driver-side valve cover and see what type you have. If original, it should look similar to the one above and make a click-clack noise when you shake it. If you still have that type I would replace it. The OE type will eventually fail, and that is impossible with the fixed orifice type. Worst case it gets plugged up. You remove it, blast some solvents through it, and re-install.

I am a big fan of the fixed orifice. I put them in everything, including old big cam small blocks. IMO it is easier to tune for a miniscule constant leak than trying to find that exact perfect PCV valve that wants to work with your combo.

Amp Wrangler · Feb 26, 2026

INW-Iron-Steel said:
View attachment 5496

I would pull the PCV valve on the back of your driver-side valve cover and see what type you have. If original, it should look similar to the one above and make a click-clack noise when you shake it. If you still have that type I would replace it. The OE type will eventually fail, and that is impossible with the fixed orifice type. Worst case it gets plugged up. You remove it, blast some solvents through it, and re-install.

I am a big fan of the fixed orifice. I put them in everything, including old big cam small blocks. IMO it is easier to tune for a miniscule constant leak than trying to find that exact perfect PCV valve that wants to work with your combo.

Appreciate that info!

stutaeng · Feb 27, 2026

I put a cheap Amazon catch can on my 06 Suburban LQ4 after I dropped in after doing a DIY freshen up rebuild...the intake was pretty grimy when I was cleaning up the parts for reassembly. I should have also upgraded to the updated valve covers, but I didn't. Seems to be working well: there are a few ounces of oil in it every few thousand miles.

The L59 I swapped into my 99 Silverado runs with nothing extra. I removed the intake once and there was a bit of blonde oil on the intake runners, but wasn't horrible.

Neither of those engines have EGR. I deleted that on the 99. EGR was only on the earlier years GMT800s, GM deleted it at some point.

Now EGR on the previous generation SBC is a really gross job. The EGR dumps carbon and makes a huge mess. Those have that goofy spider injection system so the injectors live inside that upper plenum, under heat, carbon deposits and gas vapors, and exhaust soot thanks to the EGR. The FPR also lives under there and they commonly leak, dumping fuel and causing the engine to run extremely rich and the ECU goes bananas trying to dial back fuel. Seen that numerous times. In my opinion, that's one of GM's worst designs ever. Horrendous. I hate that system!

Amp Wrangler · Feb 28, 2026

INW-Iron-Steel said:
View attachment 5496

I would pull the PCV valve on the back of your driver-side valve cover and see what type you have. If original, it should look similar to the one above and make a click-clack noise when you shake it. If you still have that type I would replace it. The OE type will eventually fail, and that is impossible with the fixed orifice type. Worst case it gets plugged up. You remove it, blast some solvents through it, and re-install.

I am a big fan of the fixed orifice. I put them in everything, including old big cam small blocks. IMO it is easier to tune for a miniscule constant leak than trying to find that exact perfect PCV valve that wants to work with your combo.

The 99 4.8 does have the serviceable PCV valve correct? I’ve read about needing to replace the valve cover with an updated version. Is it possible to tell if I need that without removing the DS rocker cover?

AuroraGirl · Feb 28, 2026

Amp Wrangler said:
The 99 4.8 does have the serviceable PCV valve correct? I’ve read about needing to replace the valve cover with an updated version. Is it possible to tell if I need that without removing the DS rocker cover?

You just need the cover. If your pcv is removable you need the 2009
If it isn’t the you need to check the part number

INW-Iron-Steel · Mar 3, 2026

Amp Wrangler said:
The 99 4.8 does have the serviceable PCV valve correct? I’ve read about needing to replace the valve cover with an updated version. Is it possible to tell if I need that without removing the DS rocker cover?