Many posts on this when searching, and even more opinions. It could cause warranty issues is all I took away from things.So do we need them as the Hemi ( from what I read) is not direct injection. Ideas, thoughts?
Of the six Hemi Rams that have been in my family, and another four of personal friends I know, none have used any oil between oil changes, at least based on the dipstick. None of these ten are using (or have) used a catch can.
In an otherwise healthy and normally asperated , factory spec. engine, a normally insignificant amount of oil is lost through the Positive Crankcase Ventilation system. Engines driven under normal conditions shouldn't require one. In an engine with elevated levels of piston ring blow-by, or lots of high(er) RPM duty, internal crankcase pressures could result in increased oil lost through the PCV. So there may be situations where a catch can would be a benefit.
If a dealer claims it causes issues (warranty or otherwise), and the catch can has been installed properly, then they're probably a shady dealer and you should probably find a new one.
One downside is the risk of condensed water freezing inside the hose and catch can.
Depending on how long one plans to keep the truck, I might avoid dealing with messy catch cans entirely.
I think a lot of people aren't aware of the difference between port and direct injection, and why it's important to have an air/oil separator (catch can) on a direct injected gasoline engine. Engines with any other injection method than direct injection don't "need" an air/oil separator. They will benefit from having one by keeping the intake and throttle body cleaner. But they are not needed. Direct injected engines do just that, they inject fuel directly into the combustion chamber. So there is no fuel to wash off the back of the intake valves and keep crud from accumulating on the back of the valves. Which can cause all kinds of problems. Poor fuel economy and loss of performance just to name a couple. This can happen in as little as 30k miles. Some manufactures like VW and Audi design an air/oil separator as part of the pcv system, which helps. But is not as effective as a catch can. And even with these systems, they still recommend doing a de-carbonization service at something like 80k miles. Some newer engines have a combination of port and direct injection, in an effort to see the benefits of both technologies. It seems to work pretty well from what I've read.
So I guess, to sum it up...the gasoline engines in our trucks are port injected. So we don't need to have an air/oil separator. But, if you want to keep your intake system cleaner it won't hurt to run one. Just make sure to empty the accumulated liquid periodically.