Front engine cover/Timing chain leak?
 

Okay I have a 2004 discovery II with 138,xxx miles on it. When I bought the truck, I was able to get a good deal on it because there was a valve gasket leak on it. Before I had a chance to fix it, it started to misfire and eventually got pretty bad. So I pulled the intake and the oil was leaking onto the coils. Since I had the intake off I replaced them and the valve gaskets. Truck ran great, no burning oil smell. About a week later I noticed the smell was back and the occasional puff of smoke from the engine compartment. I took it to a buddies shop and put it on his lift. It seems now it's leaking from the front of the engine But while on the lift I noticed there is also a coolant leak coming from around the same place. Now, I was wondering. What is pressurizing the system to cause these leaks, I'm about to replace the pcv valve, and when get a chance I'll replace the timing chain cover gasket.I'm also going to have the coolant checked for CO2. I would like to know if there is anything else that might be pressurizing the oil system.

Yep, do a gas test and pressure test on the coolant and check the pcv valve.

On an 04 it's almost impossible to get the pvc out without removing the passenger side valve cover and getting to it from under the valve cover, and then under the baffle in the valve cover. You can pull the hose off from the top and see if you can blow air though to see if it's clogged. If it's totally clogged and no air will go through, it will need to be cleaned one way or the other.
a few have succeeded in getting the pcv tube out of the valve cover from the top using vise grips but,most wont budge and you don't want to crush or damage the tube, so first see if it's clogged using air and then go from there
You can try spraying a little brake cleaner or carb cleaner in the small hole where the pcv is hiding in top of the valve cover to see if it will go through. (wear safety glasses, that stuff will blow right back in your eyes)

also check the oil for water (when oil has water it's white and slimy, you'll be able to see if it's in there on the stick probably)

also scan for codes. get your misfire codes. you can have it scanned at autozone or one of the chain parts stores if you don't own a scanner. write all of the codes down and hang onto them. don't let the parts store try to sell you anything to try to fix any codes just yet. most of them don't know much about anything.

check the plugs on the cylinders with misfires for steam cleaning...to see if you are getting water in those cylinders. ( be extremely careful putting the plugs back in, start them back in by hand, don't use a socket and ratchet to get them started in. the threads are easily damaged and you do not want to cross-thread any)

are you loosing coolant? low in the tank? if so how often do you have to add coolant? every day, every week, every 10 miles, 100 miles? a little, a lot?

more things you may need to check but, the above is where I would start.

If you do have a leaking timing chain cover gasket you will lose both oil and coolant. With 140k if your pulling it apart to remove the front cover you might as well plan on replacing the timing chain and oil pump. And then why put an old waterpump back on? Oh and of course you have to drop the oil pan just to remove the front cover. You should also be concerned with possibly of coolant migrating into your oil thru the timing cover..

Let me ask you drowssap I've got an oil leak somewhere up front. It isn't an obvious one however. I know that im getting oil dripping down on the oil filter so I know the o-ring on the filter connection is a possibility. I'm not getting coolant in the oil however.

What makes it hard to track is that the oil drops on my driveway aren't directly under any obvious engine component. But somehow I keep getting oil on my steering damper?

Sorry to derail the thread.

not drawssap but, you may want to check the oil cooler blanking plugs. One of mine was leaking bad once and blowing all over.
just a thought.

@ DiscoRover, had a similar leak on mine and both the oil pressure switch and oil filter adapter o-ring were to blame.

you just have to clean the hell out of it and recheck it, there are a dozen things that could leak. A front cover gasket in not unusual mine when at around 80k