I feel like an idiot. After a couple of months I was struggling with the water pump, removing alternator, AC compressor trying to track down the leak.. I finally found it! The front cylinder head freeze plug expansion plug had come out. The coolant was trailing down from there past the upper weep hole.. making me think it might be inner timing cover seal rupture where it mates to the coolant Galley machined into the block. After finding this picture.. bingo! Could be that freeze plug. Went out, took a look and sure enough.. it was just lying there between the head and the inner timing cover.
Problem is.. getting it back in there. I put the original part back in the hole without any RTV and managed to pry it back in place to some degree. Took the thermostat housing back off so I could get a screwdriver and a variety of objects through the little Gap between the thermostat housing galley and the timing covers. Any suggestions how I might be sure it's in there secure. Very little room to work with to hammer on something, can't get anything straight at it. Maybe somebody's found a good solution for this problem?

 

Awsome....

I replaced Mine years ago when I had the cover off. My suggestion is to pull the intake down even the Lower. Replace the KS while your there and you'll thank me later

You'll need to stack up and Glue some washers together until you get the thickness right and they protrude past the plug giving you something solid to pry on. A flex magnet will come in handy.
Other than a short pry bar and some Good Sealant around the plug, youll need to push like hell to get it in there..

 

awesome job!

what a horrible place to put freeze plugs though. if I ever have that issue I'm just going to throw in a 7th gen engine. might as well if putting in all that effort.

 

That douche bag PO. They had a leak and kept dumping in water till it froze. People like that should be exiled and castrated.

 

Thanks guys! What is the KS? Good tip on the washers. Hadn't thought of that. I'm going to try the biggest quarter inch socket I can put in there and run the extension through the gap of the thermostat housing galley. Might be able to hammer it into place that way. Prying against the timing covers makes me nervous as hell. Really don't want to take the lower intake manifolds off. I think the gaskets are over $100. I've managed to pry on it pretty good. But I don't think it's really seated until it's pushed below the bevel all the way around. Now that I've got it wedged in there.. don't want to take it back out for sealant. if I can knock or pry it back in there far enough some black RTV around the outer edge should hopefully be enough to seal it. Definitely a relief to have found it. Should have taken a look up top a long time ago . Hopefully this will help somebody else. If you've got a leak from above the water pump.. it's easy to mistake it for the weep hole. Check the freeze plug! Wish me luck. Thanks

 

knock sensor

IM is very easy to remove. You don't need a new gasket unless it delaminates and even then you can just RTV (spray would be real easy and clean).

 

of course! Duh. I think I may have managed to pry, hammer the plug into place where it is unlikely to come back out. Getting some sealant around it remains a challenge. Thanks for the tip on the gaskets. do these Maxes have a knock sensor issue? Had a Ford F-250 Triton V8.. and they just won't stop knocking . I suspect this isn't a problem with the maximas.. but anytime you've got the upper intake off, it's got to be a great opportunity to go a little deeper and replace the knock sensor. I'll do some research. Leaning your direction. Thanks a lot :-)

 

No. You'll know if it fails, b/c it'll be so slow and run like ****.

 

well she's back together and seems to run good. Needs a radiator. I had looked up top for the coolant leak.. but I needed to get out a mirror to peek in the crevice between the inner timing cover underneath the camshaft where that upper freeze plug is located. If that is leaking it will Trail down the same path as the weep hole. Wished I had found it a couple of months ago. Lesson learned. I managed to pry and knock it back into place without removing the lower intake. Pushed a tool back in there with some Marine JB Weld for good measure. Not leaking. Hasn't popped out yet. But I can't drive her until I replace the radiator. Here she is. The first photograph is the one hose I can't find a home for. It runs to a fitting at the top of the differential. Also.. I managed to get the knock sensor out without removing the lower intake manifold. If your hands are small enough you can get in there. My harness only had one wire running to the sensor. The second lead was capped off. The new one I got didn't fit the harness receptacle. Putting it back in was a b****. Chewed up my hands pretty good.

 

Yep, it grounds to the engine. It's a piezo microphone. Well, good thing it didn't fit, b/c the resistance would've been wrong.
I was gonna recommend JB weld and forgot. Good choice.

 

The hose connected to the trans does not connect to anything, it's just a vent. Remove that bolt and you'll be good.