Parnelli Joneser

I'm set to replace the cracked expansion tank in my 83 S today (among other things). I've read the various hints and maintenance tips and it looks like I'd be wise to not attempt to open the block drains. I don't have the gaskets, or O-rings that need to be replaced if I do anyway.
Does anyone have an opinion either way? And where can I source those gaskets, if I do?

As background, this car is very much an unknown quantity. The original M28/12 300 hp was replaced by a US spec M28/20 engine but the CIS intake was kept in the car. This was done by the PO because he mistook an oil cooler leak as a engine internal problem. I got the original engine in the purchase.

Thaddeus

I'm facing the same dilemma with my 86, now undergoing timing belt surgery. I'm wondering about "other methods" of getting the old coolant out of the block...

shaaark89

should be very straight forward. i just did it yesterday in the '90. 2 13mm bolts with aluminum crush rings. you may have to apply a bit of pressure but they seem to always let go in my experience (i've done it 7 or 8 times on various cars.) i normally use an offset box wrench to do it.
the crush rings are available from any of the big three. probably could find them locally as well.
make sure you have a big pan to catch the coolant because it will fly out of there.

GlenL

Those plugs have metal sealing rings. You can re-used them if they're in decent shape.

There's really no good alternative to removing them if you want to get the coolant out of the block. The hoses are connected too high to drain much through the radiator or by removing the hoses themselves.

Some have used pumps annd snaked a hose in. Maybe someone who's done that can elaborate.

I'd suggest removing those plugs. Make sure to use plenty of anti-seize when replacing. Fe into Al bathed is H2O is a formula for corrosion.

Rez

Mine come off easy enough. Use copper anti-seize when reinstalling to prevent freezing. It's worth pulling them if you want to do a good flush.

Parnelli Joneser

Thanks for the quick feedback everyone, I'll update later about how the job went.

Bill Ball

I'm going to make the blasphemous suggestion that you do not necessarily need to pull these plugs. Double blaspheme - depending on the softness of the water in your area, you can just flush with your garden hose like crazy until the effluent is super clean, then button everything back up and add coolant. This gives you about a 50/50 mix. That's what I do. [Actually I add just a gallon of coolant then top off with water to get a 75% water mix - water transfers heat better than coolant and 25% coolant is enough protection for any climate zone I may enter.] Flame suit on.

Garth S

Hey Bill,
Is that flame suit big enough for two?
If all I need to do is a coolant change out, or something simple (like repair of an expansion tank) - removal of the thermostat and the rad hoses allows for ample flushing of the rad and expansion tank with the hose alone.
For the engine, wrapping a towel around the hose end and stuffing the most appropiate engine orfice at full blast provides a very good flush: To make it an excellent flush, start the engine while the hose is on and inserted into the pump suction, and the waterpump will add to the flush.
You are correct in observing that nearly 8 liters of water remain in the block: This is no problem if the antifreeze added is of the long life (~5 yr) organic acid type that specifies tap water as the dilutant (not distilled/demin/deionized). ; Add 8 liters and top off with water.

dr bob

Depending on how your coolant has been maintained over the life of the engine, you may decide to not pull the plugs. Bill's suggestion is good if you can be sure there are no rocks/deposits/etc sitting in the bottoms of the block galleys. More than a few listers have reported using a probe to get the debris out of the plug holes so the coolant would flow, after pulling the plugs out. Seems that anything that precipitates out of the coolant wants to do it inside the block.

At least one lister here posted that the torque required for resealing the plugs is a lot less than what the FSM suggests. I don't have the torque value handy, but remember that he mentionsed the FSM value is way too high. So go with "just enough" and avoid breaking off the bolt in there.


Good luck!

Randy V

Most times, those plugs come out fairly easy if the bolt heads haven't been stripped previously.

Don't have a heart attack when you hear a loud 'CRACK' noise as they let loose. This is typical.

I contend that in order to remove any heavy sediment and other deposits that sit in the low areas of the block, the block must be drained and flushed - requiring the removal of those two bolts.

As Rez said, use anti-seize when reinstalling 'em.

UKKid35

I've removed coolant both ways, by flushing as described by Wally previously and Bill above, and by removing those pesky plugs. I couldn't even find them the first time I tried!

When I did find them (months later) I only managed one side initially as the air pump line was in the way on the other side. Someone had used copperease previously but they were still very tight and as Randy says they do "crack" when they break free. Make sure you use a socket and not an open or ring spanner otherwise you will round them and they will never come out.

Big Dave

I've pulled mine a couple of times and re-used them with the same washers. No problems.

Jfrahm

Shop vac. The killer coolant recovery system. It really makes this job easy.

-Joel.

heinrich

they have a habit of stripping, and the angle at which you have to reinstal them is ... dangerous for cross-threading. I avoid it.

geekapalooza

http://nichols.nu/tip154.htm

I did it per Wally's writeup, as I was wary of stripped / broken block plugs. It took longer to flush using this method, but the end result was the same, plus I didn't have to gamble on the block-plugs breaking.

HTH