2.5L Question

[UNCC_99XJ]

I know this isn't about XJ's, so I would assume OT is the best place for it. If somebody else feels otherwise, by all means feel free to move it.

My buddy has a 96 Dakota with the 2.5L 4 banger, 5 speed manual tranny, 2WD (yeah i know a real power house). Anyways, we were messin with it the other day and I happened to pull the air filter out and noticed the back 1/4 of it was covered in oil, much like the early 4.0's do with "blow-by". I would have to assume the PCV valve is gummed up (the engine has 130K on it, all orig. parts to our knowledge). It runs ok, does seem to be a little weak on the power side, even for a 4 cyl, but I have a feeling this type of "blow-by" issue is partly to blame for it. To my understanding, isn't the same 2.5L in XJ's as well as YJ/TJ's? I know its probably not the EXACT same design, part for part, but it aught to be pretty darn close. So, where the hell is the PCV valve on it??? I went to napa and looked at their Chiltons manual, and it lists it coming out of the side of the valve cover, near the front of the engine. We pulled that hose off today and no PCV valve anywhere in site.

He's tryin to make this thing last untill April when he's hopefully gettin an XJ, so any help is appreciated. Thanks in advance.

 

[Lincoln]

I'm almost postive those 2.5's are a completely different design and don't share anything with the AMC 2.5.

It might just have an open vent then a vacuum line on the other end of the valve cover to control the pressure. If that is the case make sure the vacuum line isn't plugged nor the baffels in the valve cover where it is attached.

 

[UNCC_99XJ]

wow thanks for the quick response!

I know i've seen a very similar engine in a YJ not too long ago, but i don't know much about them or their history, so dont quote me there.

The setup is it's got one breather line that runs from the back of the top of the valve cover to the back of the air filter box, which is the line the oil is being blown through (obviously), and another line that runs from the drivers SIDE (not on top) of the valve cover, to up underneath the throttle body (but not directly connected to the TB)

Sorry i can't be any more descriptive. I'm not a huge engine gear head yet, but I do know the basics though.

 

[Lincoln]

Check the line heading the the TB and see if it's plugged. That would be the line that always plugged on a Cherokee.

It could just be standard blow by also. If the vacuum line is working correctly check the compression of the motor.

 

[UNCC_99XJ]

We pulled them both and neither were clogged up. Really is starting to get annoying...lol. Other than this little blow by issue, the engine doesn't use or burn a drop of oil. He did switch over to Mobil 1 3K ago for the first time, could that have anything to do with it?

 

[Lincoln]

The mobil one could have broken a lot of crude loose inside the valve cover. Have you pulled the rubber gromet the line goes into? That could be plugged. Also there is probably a baffle in the valve cover. That could be plugged with crap.

 

[UNCC_99XJ]

we're really trying to avoid pulling the valve cover, b/c neither one of us have a torque wrench to put it back on with, but it looks like we may have to, to get a better look at things. Any more suggestions, keep em commin!

 

[UNCC_99XJ]

Well I had to go down to the dealer today and order a stupid actuator for my Jeep, and I asked them about the PCV valve on that engine, and there isn't one. So we ended up ordering new breathers (and a new elbow at the valve cover cause we snapped the old one). Only got one breather (from the VC to the Intake), the other one (from the VC to the air box) has been discontinued, so we ended up having to make our own. New hoses, new air filter, and a newly cleaned Throttle Body, and she's runnin better than ever. Thanks for your help.

-Tim

 

[ren]

the motor in your friends' truck is the Chrysler 2.2/25 assembly. it is mech. the same as the front wheel drive motors in the shadow, lebaron, daytona turbo(hint,hint), and so on. the biggest difference is the motor mounts. ALSO, if the engine EVER overheats, then you can pretty much expect to replace the head, as they are FAMOUS for warpage, and run like total @sh, after they get hot.

 

[8Mud]

There was a thread on Pirate about a guy that used the bell housing from a 2.5 (I think 90) Dakota, to bolt a AX15 up to his four banger.