W-22 Radiator coolant drain plug

[Max Hubrich]

I looked at the radiator coolant drain plug several times over the past few years and was always wondering why it looked like it did?? It is not like the old metal petcock style (similiar to a small Winegard "bat wing" antenna) that many of us dealt with over the years.

I finally figured it out, and oh, by the way, it is located on the lower left corner -- Drivers side, (engine side- facing to the rear).

My mission was to change out the coolant -- along with a good flush.

Before I go any further, I know, unless you completely dissassemble the engine you cannot get ALL the old fluid out-- kinda like changing transmission fluid.

Oemy has a flush procedure on his site -- Tech tips -- that is much more thorough.

I wanted to see the condition of the old coolant before I used Oemy's flush method.



First thing you need is a 1/4" drive ratchet with a 4" extension-





Here is a picture of the "little Devil" white nylon drain plug-- In the open position-- That's coolant coming out.



Make sure the engine is cooled down -- not hot!!

The 1/4" square of the 4" ratchet extension fits into the square drain plug hole.

Now, this is where you must be extra, extra careful---

1- Gently, very, very gently, turn the drain plug just a WEE BIT counterclockwise. You will feel a little "snap"-- It is now unlocked and will start to seep.

2- Now you gently, very gently-again, turn it counterwise a little more (like a quarter, to a half turn) and it is now fully extended--about a half inch (as the picture shows). Go no further-- Do not try to remove it completely-- If you do, you will be probably buying a new radiator!! I understand there is an "O" ring inside the valve that does the sealing.

3- Now move your bucket or pan under the rig and open/remove the radiator cap. Stand back as the fluid will now gush out.


Here is what my fluid looked like---


My fluid was "sparkling clean" no debris, dirt or rust at all.


After 6 refills of water, running the engine each time, with the dash board heater valve set to the "full hot position" this is what the last drain of fluid looked like---




When your all done, the radiator cap should be in this position. The arrows (which I highlighted) should be parallel to the vent tube to the overflow tank. This insures thet the cap is seated properly.



Because my old fluid was so clean I used Dex-Cool (the pink stuff) as the refill type. A completely empty system will hold about 24 1/2 qts. I bought three gallons (only used two) of the full strength stuff and mixed it 50/50 with water.

It took about 4 hours to complete this coolant change because of the run/cool process.

Believe it or not, the hardest part of the whole operation is getting the radiator cap on and off. It has two definite settings and you must push down hard to release it from it's second locking step.

The drain plug itself was a piece of cake!

Good luck to those folks who want to "Do it Yourself",

[Noleakman]

Bottom radiator hose come's off alot easier and makes a quick drain, get's more junk out!

[RetPay2]

Don't forget the block drain.

[Noleakman]

Fill with distilled water and run till thermostat opens and drain again good to go I have heard of people breaking off the plug in the block

[Don and Kim]

OK, I've started my spring maintenance on my coach. I thought I would start w/changing the antifreeze. I opened the petcock and only got 1.3 gallons out so far. Where's the rest of it? Also, where's the engine block drain? Thanks, Don

[DriVer]

Quote:

Originally Posted by Don and Kim Where's the rest of it? Also, where's the engine block drain?

Don, The block drain is in between the #2 & #4 cylinders on the right side of the engine looking from front to rear. Quite a few shade tree mechanics removed their lower radiator hose.

On a Winnebago there will be coolant in the Motor Aid system as well. The heater core will also hold a quantity of coolant as well. Draining all that stuff down may take a little time and effort.

[rogueii]

I did the change, by removing the radiator plug and draining, realized I didn't get it all out, so I used the Flush Kit and Omey's method. Hook up the T in the heater hose and flushed the system clean. I also changed the Hoses while I was at it.

[Max Hubrich]

Roguii---

Good for you--

Did you see any trash in the system, especially when the lower hose was removed?

[Don and Kim]

Follow Up. Finally got around to finishing the coolant change. After only getting a gallon + out of the radiator petcock I hooked up a compressor and pressurized the radiator. There couldn't have been more than a couple of pounds of pressure,but that blew out another 2 gallons. Removing the engine drain plug got the rest of out, probably 5 gallons total. The old antifreeze looked just like the new stuff I put back in. Replaced with Zerex brand of dexcool and distilled water.

[DriVer]

Quote:

Originally Posted by Don and Kim The old antifreeze looked just like the new stuff I put back in. Replaced with Zerex brand of Dexcool and distilled water.

Don and Kim, That good news. Just keep your coolant looking like that all the time and I expect that you will enjoy a healthy cooling system problem throughout the life of your vehicle.

For those with this question or concern, add Dexcool and water to the system as a 50/50 mixture throughout the entire process. Back in the day, I would be glad to stuff 2 gallons on conventional anti freeze into a system and then top it off with water. Not so with Dexcool. The mixture proportion is critical. Adding Dexcool to the recovery bottle later on? ... again use only a 50/50 mixture.

[DonavonP]

Fantastic presentation Max. Thank you!!

[rogueii]

My old antifreeze was clean and clear when I changed it. Had 5 years and 29,000miles. Hoses were in OK shape, but I felt safer changing them out.

[DriVer]

Quote:

Originally Posted by rogueii My old antifreeze was clean and clear when I changed it. Had 5 years and 29,000miles.

rogueii, I think 5 years is plenty of time to have an original load of anti-freeze and it was I believe time to do the change. It would take you apparently 20 years to clock up 150,000 miles or the life expectancy of the anti-freeze.

[oemtech]

The fact that it was "clear a bell" really does mean that it is good. The only way to be sure is to have it tested. But this isn't practical and cost effect for all the various fluids installed on our cars, trucks and motor homes. For me the cost of oil changes, brake fluid and coolant are cheap maintenance. Rear axle lube and tranny fluid are a bit more expensive and don't need to be changed as soon as some of the other fluids.

Example - I have the oil tested (Black Stone Labs $42.50) on my toad (97 Honda CRV - 155k+) and the TBN (Total Base Number) showed I had about 35%-40% of the additive package left at 5k.... But, the TAN (Total Acid Number) was getting high. So, I am back to 3K oil changes and will test the oil again.