I don't think it makes a difference. The pressure on the block drain plugs is from the coolant in the engine, which is still full to above the water pump, where the hoses go to the radiator. When you drain the radiator first, you only drain it, the bottle and the coolant in the engine above the hoses.

Matt

 

6 of 1 half dozen of the other. the block is still going to hold a lot of coolant no matter if you drain the rad first or last.

But that said, I would drain the rad first so you wont have to lay in any spilled coolant from the gushing block drains

 

Either way, it sure beat how I did it the first time before I started to hang around here.

I grabbed a bucket, a funnel, and disconnected the lower radiator hose. Talk about taking a bath in antifreeze… that funnel didn’t even stand a chance. I have to admit it was quick, but messy.

I didn’t know that stuff was toxic until watching 60 Minutes later that day. They ran a story about a wife feeding jell-o laced with antifreeze to off her old man.

I immediately showered after that aired.

 

IMHO the order is not important but it's a good idea to have all of the drain plugs out and the cap off at the same time, at some point in the process. IIRC I did the rad, then the block, then more came out at the rad.

 

THANKS to all for the great comments, feedback and tips. Excellent information!!

 

While all the drain plugs are out, it's proabbly not a bad idea to stick a hose in the coolant reservoir and flush the system out a bit. At least, that's what I do.

 

Finished draining my coolant this week after doing a RMS/clutch R&R: with the car on a hoist, reinstalled the rad plug after draining and filled the system with clean water until a healthy flush flowed from the block drains ... then drained the rad, and repeated a second system flush.


As we know the system holds ~16 liters/4 gal, no pre mixing done ... simply dump in 2 jugs of antifreeze, and top up with water as specified by the coolant container. A 50/50 mix will handle the far north, so good anywhere.

 

Garth what coolant did you use??

 

Hey Stan,
Looks like I made the same wise choice as Dwayne .... the Prestone as shown in post 1 .... with the exception that our northern supply is the colour of moose urine - not the same old conventional lime rickey ...

 

Many of us are unfamiliar with the color of moose urine. We lead sheltered city lives, and all the moose hang out in lodges just up the street from the elks and JC's.

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I'll second the recommendation about replacing the radiator drain plug. Cheap to do, fragile when crispy, and likely to fail on the loneliest highway sometime soon. At the same time, the reservoir cap is a replacement candidate. Cheap, very easy to change, helps keep the car cooler. Really! Orfder the genuine Behr cap from your supplier when you order the plastic radiator plug.

My experience with our "self-burping" systems is different from Stan's. Car nose down, fill the reservoir to the top. Start the car and let it warm up some. As the guge comes up, I rev the engine a few times to push entrapped air out of the top of the water bridge. Fans coming on is a sign for me that circulation is correct through the radiator and it's OK to put the cap on and clean up. Monitor coolnat reservoir level for a few dys of driving, top up as needed.

I use the Zerex G-05 at low dosage here in the warmer SoCal climate, a gallon of coolant to a little more than three distilled water. I alaos use one or maybe two bottles of Water Wetter in the mix.

The block drains deserve a bit of sealant/anti-sieze, and new aluminum seal washers if you use anti-sieze. I lke plumbers thread sealing paste with teflon, in a tube, for this duty. A little smear of Hylomar or HondaYamaBond on the threads will do the trick as well. With the sealant, you only need 15lbs/ft of torque on the block drain bolts since the threads are doing the sealing rather than just the aluminum washer.