Nomad

Hi All, I just bought a '97 Cherokee 4.0 Sport. The PO put on an aftermarket air intake, but opted not to reconnect the hose that runs from a tap off down stream of the air filter to the top of the valve cover (to the CCV air inlet). So currently ambient air is being sucked into the eng vs clean filter air.

Is this hurting my engine? I am thinking that moinsture and everything else is being drawn in there. Please let me know your opinons?

Thanks!

4jeepers

You should reconnect the hose as without it pressure can build in the crankcase causing oil leaks etc.

dukie564

absolutely necessary. You're sucking dirt and such directly into the engine internals that way. Either find some way to connect it to the air filter, or buy one of those mini cone filters at the auto parts store to put on there.

Nomad

Thanks, just wanted to make sure. Odd because the guy I bought it off knows his way around jeeps pretty well... he claims it does no damage at all. Can't see how that could be though...

freegdr

the rear hose must go to vacuum source it sucks out crankcase pressure when at idle or constant speed the front hose on the valve cover must be connected to filter box orair inlet tube or you will blow oil out dip dtick tube or into charcoal canister or next weekest link like valve cover gasket

Nomad

I follow what you're saying on the rear hose being the vacuum source, but if the front hose is disconnected air will still be pulled in won't it (just not filterer air). So, I wouldn't think pressure would be an issue, just potential grit in my eng.

At this point, is there anyway to ck for damage done? I will install a hose tomorrow, but my main concern is what damage has occured? Runs perfect, oil appears clean, no leaks anywhere...

Anything else I can do?

Thanks!

freegdr

you will not have suction from the hoses on the valve cover the will blow air out from crankcase pressure which these hoses puul out to releave the pressure the motor creates when running

EVcherokee

Incoming air should always be filtered. Theres no way to determine any damage, but any noticable damage is unlikely unless you've been in some severe dust for extended periods.

Probably the most important role of CCV and PCV systems in to vent fumes(exhaust) from natural blow-by in the crankcase. The fumes, if not vented, can make your oil acidic and attack bearings, weakening them. This happens anyway and its one of many reasons to change oil regularly, but not venting your crankcase makes this happen quicker.

If you have excessive blow-by, like many of us do, the CCV system can become overwhelmed and not work properly, its simply not designed to move that much air. Switching to a PCV system I don't think can be done because of all the stupid electronics, but heres some ideas:

One option is to use one of the first crankcase ventilation systems used, called a draft tube. Basicly you run an valve cover filter on the front hole(or run it to your air box), and run the rear(the one that goes to your intake) to a hose that goes for a couple feet under your rig. These only draw crankcase air when your moving down the highway and not as effectively as a PCV or CCV system, but if you have excessive blow-by, it will vent over pressure and oil that usually carried with it. I'm currently running a draft tube because of blow-by issues and oil was seeping down my intake tube and fouling my AIC motor and making a mess in my intake.

Another way to vent the crankcase involves welding a tube at an angle on your exhaust system(usually the collectors) with a backfire valve(s) on it. I don't know enough about them to say anything about their effectiveness, but I've seen them on a lot of older classics and drag cars. I suspect they only work well on higher RPM motors.

An advantage of running either a draft tube or a scavenge system is that your not sucking all that crap into your motor. Intake and valves will stay cleaner longer and plugs stay cleaner as well. If you can, stay with the CCV system because it creates a vacuum in the crankcase helping with leaks, but more importantly, improves performance and MPG's.

jasonzeh

get a small breather filter, it should push right into the inlet if you use a pcv groumet

dukie564

you're a bit behind pal...

smithj

Wold the rear tube, if missing, cause the engine to basically crap out if accelerating.