Engine coolant drain plugs

[Bitsyncmaster]

I've never removed my engine coolant drain plugs. Will these be a pain to remove? Should I use my air impact for this. Guess I will need to get that socket with the square fitting after all.

[EdR5150]

Got the proper external square socket? Got access to the drivers side one?

I couldn't get any leverage on the passenger side one with the car on the ground. I couldn't get good access to the drivers side one with the exhaust and cat in the way. Carburetor Bill was always talking about galvanic corrosion fusing those plugs to the block. I also remember reading DPI Josh saying he found a crack in the block starting at a plug. But, I've heard Dave S say he's never had a problem removing them. Either way, I gave up on those plugs.

[Ozzie]

Mine came out, but with a breaker bar, one side was tougher than the other.

Was interesting because the plug came out, but no coolant came out. huh??
I looked in and found 30 years of sediment on the plug hole.
Picked at it carefully, started seeing a little drip of coolant come through, then a little more picking and finally the stream of coolant broke through. Cleaned it all nicely before I re-installed the plug.

[jmettee]

Both of mine came out fine with a normal 3/8" drive ratchet. Since I'm cheap & innovative, I took a large bolt & ground it square with a grinder to make a square socket for those plugs. Worked like a charm. I made it a snug fit to minimize the chance of rounding the plug.

Mine also had sediment, but not enough to clog the hole. They started dripping while I loosened them.

FYI, the copper washers are the same as the one on the oil drain plug.

[Morpheus]

On both my cars, my experience was similar to Ozzie's. The end of these plugs tend to corrode and become one with the block. A couple of taps with a punch broke the corrosion free and coolant flowed everywhere.

Accessibility is tough with the cat and oil filter in the way, but I suppose with the right extension you should be fine.

[Jason]

I just did mine a couple of weeks ago. Probably the first time they've ever been removed. I used a breaker bar and square socket. It took a scary amount of force, but they both came out without any problems. I did end up leaving the drivers side one in until I had the engine out of the car and the exhaust off. Since the engine was coming out anyway why struggle with access.

[Bitsyncmaster]

Thanks for all the good info. Was that plug a 5/16" square? I'm thinking of grinding a allen head socket to fit. Will need to keep it cool when grinding so the temper stays in the tool.

[tgraham]

Was that plug a 5/16" square? I'm thinking of grinding a allen head socket to fit.

The 8mm square drive used for the stock oil plug can be used on these engine plugs (maybe a 5/16" too since it's awfully close, but the 8mm definitely works).

Travis

[jawn101]

So I assume you guys are all taking these plugs off to do coolant flushes.. how do you pressurize the motor and flush out the water jackets? What do you use? I'm guessing distilled water?

[Morpheus]

I only un-plugged mine to drain the block. I have no idea how to flush the water jacket.

[stevedmc]

I only un-plugged mine to drain the block. I have no idea how to flush the water jacket.

Remove the lines connected to the water pump and blow it out with compressed air. Or you could remove the thermostat and blow air in one drain hole. The moisture will work its way out the other end.

[Bitsyncmaster]

Passenger side came out no problem. It gushed out and really flowed when I removed the bottle cap. My car has 28 K miles. Coolant look pretty clean.

[Bitsyncmaster]

Here I thought the drivers side was easy. The plug I pulled had some oil come out (above the oil pressure switch). I don't even see the coolant drain plug. This plug HAD a hex drive.:strongman:

[Morpheus]

​Post a pic?

[Bitsyncmaster]

​Post a pic?
I had to find my eye loop to read your reply.:elmo3:

Do you mean a photo of the plug or where it came from?

[dmc6960]

Here I thought the drivers side was easy. The plug I pulled had some oil come out (above the oil pressure switch). I don't even see the coolant drain plug. This plug HAD a hex drive.:strongman:

Yea, that was an oil passage. The driver's side is near impossible to get at with the CAT in place. It'll have a square drive just like the passenger side.

[Bitsyncmaster]

Yea, that was an oil passage. The driver's side is near impossible to get at with the CAT in place. It'll have a square drive just like the passenger side.

Thanks. Guess I don't need to pull that plug. I was just going to do a flush if I saw any build up in the cooling system before I install the new radiator. Guess I will weld a hex nut on that plug I damaged.

[DMCMW Dave]

Yea, that was an oil passage. The driver's side is near impossible to get at with the CAT in place. It'll have a square drive just like the passenger side.

Don't you people have socket extensions?

[Bitsyncmaster]

Don't you people have socket extensions?

I did not get far under the car. I guess you could see it that way.

[Morpheus]

I had to find my eye loop to read your reply.:elmo3:

Do you mean a photo of the plug or where it came from?


I'm not sure why my font size shrank down like that, sorry.

I was referring to where the plug came from.

[Jason]

Just in case this helps, since I have a stripped block handy....

12596

[Bitsyncmaster]

Just in case this helps, since I have a stripped block handy....

12596

Thanks. Now I know where to look.

[EdR5150]

I decided to try the coolant plugs on my junkyard 3.0 PRV. I had previously soaked them in penetrating oil. Access couldn't be easier since the engine is on a stand, without exhaust. With a breaker bar, socket extensions, and the Snap-On external square socket, they came right out.
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There was a buildup behind the left one that I had to break through with a screwdriver.
1260512604
One the right side, a black coolant mess gushed out. I can also see a thin shimmer of oil on the coolant but hopefully that's oil that the coolant washed off the block.
12603
I put a thin amount of antisieze on the plugs, and loosely reinstalled them.

[Bitsyncmaster]

Don't you people have socket extensions?

Once I knew where it was, it was easy removing it. Same results, coolant gushed out. Just used a long extension. It's right above the CAT but can only be seen if you can get your head up there.

[DMC5180]

In the mid 80's, Volvo installed Drain valves in place of the block plugs starting with the 760 series. The Valve looked like a larger version of the cooling system bleeder valve. You could attach a hose to it.