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Look from under the car up towards the passenger lower corner of the radiator. I have to remove the plastic slide out oil change access panel. My OEM had a 1 inch diameter plastic phillipshead screw. My replacement one has a plastic wing nut. Just remember it will be on the lowest part of the radiator somewhere.

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Having replaced coolant on my boxers many times, I have been searching for the right way to get all the old fluid out and getting as much new fluid in, without having to burp the system for a week after I'm done. I think I have finally cracked it!

 

Draining

 

Drain the radiator as far as possible with the little "faucett", and then detach the lower hose from the radiator. (If you are like me, replace any coolant hoses that you remove, and use stainless steel clamps on the new ones)

Even more fluid will drain from the radiator, and some will drain from the engine block. Detach the upper hose from the radiator, and run clean water through the rad until it comes out of the bottom clear in color.

 

Now, I do not contest that the best way to flush the engine block is by unscrewing the two drain plugs, but these are often seized and could turn into a source of trouble if you strip the threads or if they won't seal tight when you screw them back in. SO, I jack up the rear of the car until the engine block is tilting slight forward, ie. wheels about 6 inches off the ground, unscrew the thermostat housing, and let the old fluid run out through the thermostat opening. (Needless to say, I replace the thermostat gasket)

Run clean water in through the upper hose until clear water comes out of the thermostat opening. Leave the car in this position until it stops dripping water.

 

Remove the expansion tank and flush it, there will be plenty of "snot" in the bottom of it! Rinse the hose too. Install the tank again and fill to the FULL mark.

 

 

Filling

 

Close up the bottom end of the cooling system, ie. thermostat and lower hose. If possible, perform the next phase on a slight incline, car pointing upward.

Get a funnel with about 10 inches of half-inch diameter hose on the end of it and slide this down the upper hose in toward the engine block. I do this because bending the upper rad hose causes it to collapse and that makes pouring coolant into it impossible. Pour your preferred coolant directly into the engine block. Pouring slowly, and pausing along the way will help keep air from being trapped inside the block. It should swallow at about two litres before it starts to rise and threaten to come out of the hose. At that point, attach the upper hose to the rad and continue to fill slowly through the rad cap hole. Once it seems full, start the engine, let it run for twenty seconds and shut it off again. This will dislodge the few air pockets that are unavoidable and the fluid level in the radiator should drop a little after the burp, top it off.

Start the engine again, and let it run until the radiator fan starts running, be patient! When then fan starts running, top off the level in the rad and install the radiator cap - and bleed screw if there is one. During the warm up, a small amount of coolant will spill over the rad filler neck, have a cloth to absorb it.

 

Take the car for a shortish run, just a few miles to get it fully warmed up, and park it on level ground. Check hoses for leaks of course, and let it cool. This will take a number of hours, overnight is good.

In the morning, note the level in the expansion tank, it will probably be a little lower than FULL. Fill to the FULL mark, and you're all set.

 

Obviously, you should check the level in the expansion tank for a few days afterward, but there shouldn't be any problems. Resist the temptation to open the rad cap, this will only interfere

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  • 1 month later...
In both of my cars, there is only one bolt holding the tank down. Remove that bolt and the whole tank comes out without much trouble. I've had good results with hot water and Dawn soap.

 

So after doing this process twice in one week, I'm having the same problem that I first attributed to purchasing a non-OEM t-stat.

 

The car will run fine for about 15 minutes or so, then all of a sudden the temp gauge will spike and the coolant reservoir fills up. Now, I know people are going to say "head gasket" but I'd like to explore some other possibilities first, as there was clearly no oil/contaminants in the coolant, nor air bubbles in the expansion tank, and the heater was blowing HOT when I slid the gauge over. I spoke with my mechanic briefly, and he said it sounds like an air pocket in the system. Is it possible, even after following this tutorial to a T, that there could be air in the system? And would that cause this sudden temp spike after normal operation?

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Quick question--

Do the cooling fans for the radiator operate in tandem? I noticed just now that only the large one came on and not the smaller one.

 

one is the main, one is the auxiliary. Turn on the ac and the 2nd fan will come on along with the first one.

 

nipper

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Well I thought that bubbles in the overflow tank=head gasket. Maybe not. Come to think of it, I recall seeing this almost two years ago when I first got the car and thinking the same thing. I would think after two years with a bad head gasket I'd be having a lot of problems. In all respects, other than the problems I've had of late, the car runs superbly.

 

I did realize that there was a lot of air in the system. Basically, instead of capping the radiator after the fan came on and I topped off the coolant, I waited for the fan to come on again. Each time the fan would come on, the coolant level in the radiator would drop again. I did this a number of times until the level didn't drop much anymore. Just took it for a drive with the A/C cranked, and didn't have any problems. I'll let it cool down overnight, then check the levels in the morning again. Thanks for the help!

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So this thing seems to be taking A LOT of coolant. Guess there was much more air in there than I thought, which is probably why it was overheating. I won't know for sure until I get that bleeder screw replaced and can drive the car a bit.

 

Couple of things I noticed that I'd like to ask if I should be concerned about:

 

1. The bubbling in the coolant, as shown in the video I posted above. I also detect an 'exhaust like' smell from the coolant in the expansion tank. The coolant still looks brand new, and there was never any kind of oil/sludge in the previous coolant, which hadn't been changed in quite some time.

 

2. As the car was warming up yesterday, I checked the tail pipe and there was a bit of water spurting out every now and then. Also a little bit pooled up at the bottom of the exhaust pipe.

 

3. When adding coolant, I followed the technique in the Haynes manual about squeezing the upper radiator hose to expel air. I can sit and squeeze that thing over and over and each time air will come out of the radiator cap and the coolant level will drop a little. I add more, squeeze, add more, repeat, etc. Can there really be that much air in the system? I'm not leaking coolant AT ALL.

 

Anyway, any input on this is appreciated. Of course if I get that bleeder valve replaced, get all the air out, and it still overheats, it's going to the mechanic for what I'm sure will be a head gasket job. But if it goes back to being as reliable and well-running as it has been, should #1 and #2 really concern me all that much?

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Anyone have any tips on cleaning out the coolant reservoir other than a baby bottle brush? Don't have one handy and I'm in the middle of this job right now. Lots of gunk on the inside of the coolant tank.

 

Put tiny, clean rocks in it and swish it around. Around here we call this stuff pea gravel and it comes from the river beds. Rocks about 1/4" in diameter.

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Put tiny, clean rocks in it and swish it around. Around here we call this stuff pea gravel and it comes from the river beds. Rocks about 1/4" in diameter.

 

Dish soap and a warm water works too, shake like a milk shake, rinse with water.

 

nipper

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I use Simple Green and warm water, then push a strip of old rag down in the tank, Get a piece of coathanger wire or an old choptick (handiest tool ever here in Hawaii!) and you can push the rag around to wipe those hard-to-reach corners clean.

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