benstoker

I recently put in a new water pump in my '90 Laredo. After burping the coolant system, I let the jeep run for a few minutes while I was putting away tools (it was sitting around 180*F on the temp gauge). When I came out of the garage, most of my coolant was on the ground. After letting it cool off, I climbed under it and found I had blown a hole in the freeze plug under the exhaust manifold. Are these possible to change without removing the motor (i.e. - can i just remove the manifold)?

tl;dr
What freeze plugs, if any, can i change without removing the motor?

austinjoe13

If you don't have a block heater now's the best time to install one!
I don't think its a huge pain..... Idk though.

DFlintstone

Pretty sure they are all on the back and the left. And, yea, I just had my manifolds off and they are right there. Once the air cleaner is off everything is much easier to see and reach.

If I wanted to get at the rear plugs, myself I'd pull the trans. I'd rather deal with that on a jack as opposed to pulling the engine.

benstoker

@austinjoe: we dont usually get temps here in GA cold enough to blow them. it was just rusted through.

@DFlintstone: thanks for the info. I'll start pulling them off tomorrow.

DFlintstone

The front Ex. Man. bolt broke right off for me. Was an hour before I had it drilled and tapped. Also I would have put new O rings on the injectors if I had them. You might want to PB blast the nuts on the header pipe and the manifold bolts ahead of time, have fun!

Firestorm500

The ones on the left side of the engine can be replaced without pulling the manifolds.

You really need a lift to do it, though. So you can get up under there and see what you are doing.

notop46

I just did mine 3 weeks ago.

Pick up a set of Brass freeze plugs (there should be 5 the same size for the driver's side of the motor), a tube of silicone, an intake/exhaust gasket, and a new exhaust flange doughnut. Include injector o-rings if they are more than a few months old.

Pull the air filter, remove the PS mounting bolts but leave the pump in and the lines installed, pull the trottle cable off at the linkage, the fuel line at the front of the manifold (bleed of pressure first using schrader valve), remove fuel rail bolts and lay fuel rail over master cylinder and remove the itake and exhaust manifolds.

Knock/pry out the bad ones, clean out any gunk that you can reach through the openings and flush with garden hoser to remove all debris (assuming you are also doing this outside). Make sure to clean the holes well to ensure good seal. Apply a bead of Silicone around the hole and the cylindrical part of the plug and press/tapthe plugs into place. I think I used a 1-1/4 socket to start mine and then a large washer with a bolt welded to it to seat them below the block surface.

Re-assemble components allowing 6 hours for silicone to cure before adding water/antifreeze.

Hope that this helps some.

benstoker

seriously, you guys are rockstars.

i am assuming the PO had the exhaust and intake manifolds b/c the bolts were quite easy to get lose.

@notop46 - your instructions were dead on. i really appreciate all the info.

Thanks!

buckshot500

EDIT; Just noticed this was already covered by notop46 in post #7

Sometimes the water jacket contains machining chips left over from factory milling. These seem to end up in the lower parts of the jacket right up against the freeze plugs. The chips rust, and that rust works on the plugs to perforate them.

While you have the plugs out, flush the jacket with a garden hose, while fishing around with a wire coat hanger to get all the chips out.

Doing this will also help the engine run cooler in the summer.

DFlintstone

And the crowd cheers! Well done, and thanks for the "chips" tip guys,

Firestorm500

I thought the freeze plugs should be installed dry with no lube, silicone, or sealer between them and the block.

benstoker

I'm not sure about dry versus wet but every mechanic i've talked to says they usually add RTV silicone to the shoulders of the plugs before putting them in so it will smear off on the sockets as they go it. also, the water in the jacket will cause the silicone to cure at a little faster pace that the normal 12 to 24 hours.

@notop & buckshot - it's crazy how much debris ends up in that water jacket. thanks for the tips on cleaning it out.

notop46

No Problem. Glad I could help. Like I said, I was there three weeks ago, so it was all fresh in my memory.

I fought the 3/8" pipe plug for 2 hours before welding a lug nut too it to get it out. I replaced it with a stainless steel pipe plug and plenty of teflon tape. This way, draining the block will be easy in the future.

Firestorm500

Stainless steel can still rust. Might have been better to use a brass plug.

PocketsEmpty

How did you make out with these? I just replaced all plugs in my '98, and to my horror, one popped out on me while driving over the weekend. Hoping my motor isn't completely screwed. I'm going to try brass ones, but first time around they were so hard to press in, I went and got the steel ones. They went in much easier---but apparently too easy. I'd be interested to hear your experience.