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Block Drain Plugs Hard Stuck


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Want to fully drain old coolant. Cannot remove those drain plugs beneath the manifold.

PB Blaster soaked for days. Roasted with mapp gas torch for a very long time. 5/16"

square tool steel cranked with as much force as space will permit. Not one budge, not

even a tiny one. Even danced on one foot with an ostrich feather in my teeth while waving

chicken bones and chanting incantations. Apparently the wrong ones. Does anyone

know the correct incantations? Or any other viable techniques I may have overlooked?

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The blocks are really hot when they screw those plugs in. When it cools down it is for all practical purposes one piece. It's welded in. Try some paraffin. Don't know why but it works better than Blaster or penetrating oil. Get a torch, Oxy-acetylene. A little propane just ain't gonna hack it. Heat the plug and rub paraffin around it. Wait for it to cool. The paraffin melts into the threads. Penetrating oil just burns off. This has worked for me on over half the plugs I've done it to. There were a couple just couldn't get nothing to budge them.

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I had one MJ overheating. Nothing helped. Flushed with hose, pressure washer, everything. Finally removed the front freeze plug. That block was so full of rust, crap there wasn't room for any coolant flow. removed the rest of the freeze plugs and between running hose and a working a cable in the jacket was able to clean it up good. Never messed with the screw in plugs.

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Just to close the loop, I cooked those little bas$$$ds for an hour, soaked parrafin into

the threads, cranked them in both directions, and got absolutely nowhere. I've decided

that draining from those points is vastly over-rated. Got the Prestone flush kit that cuts

into the heater hose, and flushed the system adequately. Got more stuff out of the

heater core (and then not much) than anywhere else. I've installed the Hesco water

pump (with the scroll impeller), the CSF 2671 all metal radiator (Hesco sells it but it can

be had for a lot less elsewhere), and the newer (from 98 XJ) 10 blade fan. Put the correct

(195 deg OEM) T-stat in, and running distilled water with 12oz water wetter. What

a difference! I can dump tons of heat now. Still planning to add the second 10 blade

fan, after thinking through the electrics for a bit. I'm concerned about the first fan.

The 98 XJ donor uses a much heavier gauge (#8 I think) for the fan than our MJ wire,

which looks like only #14. I'm thinking about pulling heavier wire through the harness,

but not looking forward to that task. (Yes, I know I could just add new wire outside

the harness). I don't have an ammeter that range, anyone know what these fans

actually draw? Thanks!

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Thanks Don,

 

I was afraid they could pull nearly 20 amps. With two of those kicking on, plus headlights,

and whatever else is running, I could be nearing the limit of my poor old OEM alternator.

I think they're good for only, what, 65 amps total?

 

Tom

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Thanks Don,

 

I was afraid they could pull nearly 20 amps. With two of those kicking on, plus headlights, and whatever else is running, I could be nearing the limit of my poor old OEM alternator. I think they're good for only, what, 65 amps total? Tom

I think the biggest alternator available on the HOs was the HD 90A; most were 65A-75A. But since you have a 92, the Dodge/ZJ 136A NipponDenso alt below is a cheap and easy bolt-in swap. I did this swap awhile ago and it bolted right in w. no case grinding. Also upgraded my mains cables. It handles both fans, H4 Hella head lamps, A/C on, and full blower no problems. A good upgrade to do on the HOs.

 

vdn11361204.jpg

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Good lead - thanks! I read somewhere that this alternator is

externally regulated, via the PCM. Hopefully the amperage

increase will pose no risk. Kelley's W.I.P. talks about adding

an inline fuse - did you do that also?

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Good lead - thanks! I read somewhere that this alternator is externally regulated, via the PCM. Hopefully the amperage increase will pose no risk. Kelley's W.I.P. talks about adding

an inline fuse - did you do that also?

 

Yes, it's regulated by the ECU based on load demand and battery voltage sensing. Same way the 91-92 MJ HO alts are, and the V8 ZJs and Dodges the 134A alts came from.

 

Yes, I did add the inline ANL fuse (150A if I recall) along w. a set of Kelly's mains cables.

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