headjob redux

[tomjt714]

Okay folks, I'll Just lay it out. Bought a '92 XLT, 4.0, 5 sp. Body beautiful. Stopped for fuel on way home, saw coolant leakage dripping down from back of engine. Ooooch. Wasn't that bad at time. Did the super radiator flush and leakage is medium steady. So, know it's either head gasket or lower intake manifold. When I investigated, hottest and wettest seemed to be at the join of the two (passenger side). Any thoughts as to it being just the lower intake? Also, with 175K would it be just as prudent to refurb heads as I'll be 90% there with lower intake. Operating on shoestring budget. Already got beat on truck, need all advice readily available. Also, what damage can I expect on getting heads shaves, boiled, etc.? By the way, piece of advice... Before buying used Explorer that looks good, pull hose off radiator overflow tank and make sure previous owner didn't epoxy it shut to camoflage probable head gasket problems.

By the way, no water in oil or exhaust. Runs on hi side of normal. Quits leaking when coolant level drops below some? point.

Thanks all.
tomjt714

[malohnes]

Sounds familiar. Most likely a head gasket, but could very well be both loose LIM bolts and bad head gasket. Might also be a bad lower intake gasket as well.

My advice, is to replace head and intake gaskets, clean the heads, unless there is sign of damage and put it all back together. Just remember to obtain new head bolts and torque bolts to specs.

[Anime]

First make sure the leaking isn't just from the heater core/hose connection or something else. Then if you want to be sure where it's leaking from, use some engine cleaner and clean up the head/block area as much as you can, then inspect with the engine running and pinpoint your leak.

If it's not a head gasket and there's no oil/coolant leaks from the heads, you might just want to leave them alone. Generally if there is ANYthing wrong with the heads, it's best to just replace them with new, aftermarket heads. The stock heads, especially the 90TM versions on 91-92's, were not very thick or strong, and are known to crack if they ever get hot from cooling issues. New heads aren't all that expensive, ~$200 per side for a complete unit. If there's no cracks or damage though, you can just put 'em back on and just replace all the gaskets.

If you're doing anything to the heads you may as well replace the rocker arms as well, which causes the valve clatter noise from wear.

[tomjt714]

WaaaHOOOO. It WAS the lower intake manifold gasket. Now, does anyone out there have a good pic of just where to apply the RTV? Haynes does a piss poor job of detailing it. Also, does anyone know of a conversion factor from inch-lbs. to foot-lbs. I'm tore up and can't get anywhere til 2morrow to get a proper inch-lb. torque wrench to reinstall intakes. Have a whopper of a ft.-lb. though. Any ideas?

Did I really ask for inch/lbs - ft/lbs conversion? Sorry folks, I'm only THAT stupid when I'm killing myself to get something to drive to work the next day. Anyhoo, still got much to do. Lower intake says 16ft./lbs - I hit it at 20. Best reliable on me torker. I'll let you know how it turns out. Still got valve covers, Idler/tensioner assembly, godawful octopuss of vaccum-sensor-electrical, and radiator to get back in. Sounds like a sick Monday......

[waskly]

if its a 5.0l where the heads meet the block the corners should be silicone.

[wood1]

Get a proper 1/4 torque wrench.

I smeared a skim of RTV around the water passages of the head and LIM before placing the gaskets. If you have cork gaskets for the front and back of the LIM discard them and use RTV. A good 1/4 bead and run it onto the head about 1/4 inch. It will smear out so don't worry. I had to trim a little bit of the LIM gasket so that the valve cover gasket would sit flat. Also a good smear at the corners of the valve cover gaskets. Also make sure you let it harden up before you start the engine. Over night should do it.

Great that it was the LIM gaskets and not the heads. Good for you!

[malohnes]

Good job! Glad to hear it was not a head or related issue. I followed Wood advice...works fine.

[tomjt714]

Part 3 of headjob. Found coolant leak at rear water jacket, passenger side LIM. Replaced gaskets from LIM up. Everything seemed fine. Old girl even ran I-79 for 16 miles @ 100+. No problems. Did final backflush 2day, put antifreeze/water 50% mix in, freeze plug back drivers side cylinder head pinholed. Am I chasing a ghost? Ready for gal gas/cig. Need vehicle in worst way, any/all thought appreciated. Pretty sure I can get old freeze plug out, replace with compression plug. But am I missing something?

'92 XLT, 4.0L, 5sp. manual

Thanks all.
Tomjt714

[Anime]

You should keep all your related posts in one thread to get the most replies and useful help from the forum. Making a new post for every single step clutters up the forum and makes it so people can't help you out unless they seach for your previous theads. Make it easier on people to help you.

You can just replace the old freeze plugs with new ones. Get the yellow zinc ones if you can. Of course it would have been better to replace them with the cooling system already drained, and then you could have just flushed it that way.

[R&T Babich]

Originally Posted by Anime

...You can just replace the old freeze plugs with new ones. Get the yellow zinc ones if you can. ...

Anime - any issues using brass freeze plugs?
I think most marine engines use them since they don't usually have antifreeze.

[Turdle]

I merged the 3 threads to help everyone stay on track. Please use one thread to avoid cluttering up the site, thanks!!

[Anime]

You can use brass freeze plugs, sure, but they are generally much, much more expensive than steel. Gold zinc plated steel plugs still give decent rust/corrosion protection without the expense of brass. Using engine primer/paint on plain steel plugs after installation is also a good cheap way of doing it.