I'm guessing a freeze plug, can't see up past the MM, it's a pretty good leak at temp. Anything thing i should know about this repair on 4.0 motors before tearing into it? I a little surprised at 116k miles a freeze plug would fail,,,gregg
Coolant leaking under manifolds
- Thread starter Brokeass Boater
- Start date
I can't think of anything else under the manifolds other than the freeze plugs. It may be worth it to put some UV dye in there just to make sure.
That is a little odd, because I can't remember the last time I heard of a freeze plug failing on a 4.0.
Not to say it isn't possible, just highly uncommon.
That is a little odd, because I can't remember the last time I heard of a freeze plug failing on a 4.0.
Not to say it isn't possible, just highly uncommon.
Do you have a block heater? If it was installed incorrectly or has corroded, it could leak. The block heater (or the freeze plug normally used for it) can be accessed by removing the power steering pump (you shouldn’t need to drain or disconnect it, just move it aside).
If you live somewhere where it routinely gets cold, this would be a good time to install a block heater. (It simply replaces a freeze plug.)
If you live somewhere where it routinely gets cold, this would be a good time to install a block heater. (It simply replaces a freeze plug.)
No block heater. Really really bad timing for me with all the irons in the fire I have right now. You guys have a time estimate for this repair that I can use to figure in when I can free up some time and tackle this. I hate working on a repair as time presents itself, I like blowing it out and be done with it,,,gregg
It depends on where it is. If it's the front driver's side freeze plug, you can get to it by unbolting the power steering pump and bracket. Otherwise I suspect you'd have to pull the headers, though I've never really took a good look at how to do so.
Pulling the power steering pump and getting under there and replacing it would be about 3 hours. That's what my block heater install took if I added some time to remove the pump.
Removing the headers and repairing plugs would likely be a 6-10 hour job. Get a new gasket, and consider installing an aftermarket exhaust header if you don't already have one, as the factory ones are known to crack. Look around and see if there are any other projects you can do while you have them off. It's not the easiest thing to remove them.
There is also a block drain below the freeze plugs behind the exhaust pipes. This block drain, if I recall correctly, takes some odd metric square size (8mm or 10mm I can't quite remember).
Pulling the power steering pump and getting under there and replacing it would be about 3 hours. That's what my block heater install took if I added some time to remove the pump.
Removing the headers and repairing plugs would likely be a 6-10 hour job. Get a new gasket, and consider installing an aftermarket exhaust header if you don't already have one, as the factory ones are known to crack. Look around and see if there are any other projects you can do while you have them off. It's not the easiest thing to remove them.
There is also a block drain below the freeze plugs behind the exhaust pipes. This block drain, if I recall correctly, takes some odd metric square size (8mm or 10mm I can't quite remember).
I suggest some UV dye in the coolant and a UV light. This should help you pinpoint exactly where the leak is coming from.
There is a head gasket below those two manifolds also. Confirm that the coolant isn't coming down from there. It would suck to pull off the manifolds and then have to go right back and pull them again.
Update on the cooling issue and more discoveries and of course a question. The coolant is traveling along the top of the flange of the oil pan, I'm guessing the water pump is the source of that. I need to get a fan pulley tool to get the fan off to pull the water pump, the fan clutch nut wants to be difficult. I'll run into town tomorrow and pick one up. The valve cover had been weeping so I replacIed it, decided to replace the manifold gasket too. It wasn't leaking, I figured why not, since I have no history of maintenance on this rig. Yes it's a pain in the ball sack, but it's all new and done. When I had the intake off I noticed there was oil build up in the runners of the head and inside the intake. Cleaned/ flushed everything thing up and is clean now. I didn't pay any attention to the plastic elbow on the valve cover when I had it off, just cleaned the gasket surface and installed it. Is that elbow a vent or true pcv, one way valve? I don't think I have ring blow by, all cylinders have 170-175psi. I google that elbow and saw some said it was and some said not. Also saw that some said it was common, sure seems like there are a lot of "common" issues with jeep s, lol. You boys here have a better pool of hands on jeep experts then the other forums.Any thoughts on oil in a 2006 4.0 intake?,,, gregg
Every engine has a certain amount of blow by. I think that there is no pcv valve. Just an elbow going to the air tube. I had an old Ford Escort (
)that loved to blow oil into the intake also
. I spliced an extra pcv filter inline. The Escort had a regular pcv and breather, but it wasn't enough. I think the Chevy LS engines have a similar problem and they put an inline oil trap on the vent tube. That could be your answer. Then you will also be able to gauge just how bad the problem is. They are made to trap the blow by oil and be emptied out periodically. Hope this helps.
)that loved to blow oil into the intake also. I spliced an extra pcv filter inline. The Escort had a regular pcv and breather, but it wasn't enough. I think the Chevy LS engines have a similar problem and they put an inline oil trap on the vent tube. That could be your answer. Then you will also be able to gauge just how bad the problem is. They are made to trap the blow by oil and be emptied out periodically. Hope this helps.
Thanks for that, since I don't know any thing about the maintenance history and near as I can tell from searching the web, I don't have a real problem. I think I'll leave the scavenging system as is and just check it periodically going forward. I'm guessing that a previous owner didn't change the oil like they should of and there was some excessive light ends running thru the manifold. No sludge build up under the valve cover, that was good to see. Went to O'Reilly s yesterday, free use of the fan clutch pulley holder and got the water pump changed out and thermostat. We had our Mothers day get together with the kids, so I couldn't finish putting the fan and shroud on, I'll get that done today. Thanks gentleman for the feedback,,,gregg
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