Advice for completing my coolant flush

[Suzu]

So my Toyota van is sitting in the driveway on ramps with a jug under it, catching the last drips of coolant that came out when I removed the radiator drain plug, and there's less than a gallon of it. When I started the job, the cooling system was full, and it takes more than two gallons of fluid for it to be full. So, where's the rest of that fluid, and how do I get it out?

I read on a Toyota Van Tech forum -- in the context of a thread on another subject -- that: "There's a petcock on the passenger side bottom of the radiator & a block drain on the driver's side front of the engine (see pics below)." Which seems to be saying that I will have to separately drain a "block" (whatever that is). Is this true? I mean, can one not remove all the coolant without opening this other drain thing?

Adding to my trouble is the fact that I can't get the plug I removed back into its hole!

I tried asking the folks on that forum for help but they seem to ignore non-mechanics looking for help with this sort of simple thing. So I ask here... hoping *someone* knows the answer!

Thanks in advance.

[acptulsa]

When you put it on ramps, you raised the radiator above the engine. But that's only part of it. Also, the lower radiator hose on many vehicles does not reach the very bottom of the water jacket, meaning the coolant passages inside the engine. So if you want to change all the coolant, you have to open the other plug.

The block is the engine. It's actually the huge casting everything else is bolted to, but for your purposes, it's the engine. Don't mistake the oil drain plug for the coolant drain--the oil pan is bolted to the bottom of the block. You may not be able to drain it completely on those ramps, since the drain is near the front, but get that loose and you will drain all but about a pint.

If you decide you want to drain it further, back it off the ramps. You can drive around the block without coolant, if it's cold when you start, but don't. But back it down immediately and turn the engine off immediately. Don't even run it two minutes without coolant.

Most radiator drains don't need to be removed; they drain as soon as they're loosened. The engine block drain might be the same way, so if you loosen it and coolant comes out, skip the headache and don't remove it completely.

Did the radiator drain come out easily? Do the threads all look even and make a nice, straight spiral? If the answers to these questions are yes, you probably aren't getting it perfectly straight and lined up right. My dad had a trick that sometimes works: Put the plug in place and turn it counter-clockwise (loosen it) until you feel a little click. Now the ends of the threads inside the hole and on the plug are right next to each other, and if you turn it clockwise the threads should catch each other.

Let me know if that helps! I know it just got dark so I'll check tomorrow.

[oyarde]

I would probably just put in neutral , roll it off the ramps , and dump whatever comes out of the bottom hose and put everything back. I would just drain whatever I get from the radiator petcock unless it is particularly nasty. Check your threads on everything , if they are OK , you just have not gotten lucky enough yet to get it lined up straight. Transmission/radiator metal lines are difficult to get lined up straight too if I recall.

[Suzu]

When you put it on ramps, you raised the radiator above the engine.

No, I didn't. My driveway has a steep slope to it, and the car is level right now. I only put it on the ramps so I could get under there comfortably.

the lower radiator hose on many vehicles does not reach the very bottom of the water jacket, meaning the coolant passages inside the engine. So if you want to change all the coolant, you have to open the other plug.

Once I get the drain plug back in, I can take it off the ramps. Then I can look around for that lower hose, I guess.

Did the radiator drain come out easily? Do the threads all look even and make a nice, straight spiral? If the answers to these questions are yes, you probably aren't getting it perfectly straight and lined up right. My dad had a trick that sometimes works: Put the plug in place and turn it counter-clockwise (loosen it) until you feel a little click. Now the ends of the threads inside the hole and on the plug are right next to each other, and if you turn it clockwise the thread should catch each other.

Let me know if that helps! I know it just got dark so I'll check tomorrow.

The answers were yes and yes, and I'll let you know tomorrow. Thanks!

[Suzu]

I would probably just put in neutral , roll it off the ramps

Actually, if I put it in neutral it won't move at all, or maybe will roll forward (into the house). My driveway has a steep slope.

and dump whatever comes out of the bottom hose and put everything back. I would just drain whatever I get from the radiator petcock unless it is particularly nasty. Check your threads on everything , if they are OK , you just have not gotten lucky enough yet to get it lined up straight. Transmission/radiator metal lines are difficult to get lined up straight too if I recall.

The fluid looks ok but it has some grit in it.

The drain plug is made of plastic. Sort of soft plastic. I haven't tried to force it. The main problem is how hot it is out there. I really suffer in the heat -- if it's 65 degrees and I'm active, I sweat from my forehead so much that after about five minutes I can't see. Today it hit 90 and when it's that hot all I have to do is breathe in order to blind myself with sweat.

[acptulsa]

Removing the lower hose is good because you can stick a garden hose in there and flush stuff out. But that won't help the engine water jacket drain, so if that's your reason for removing it, don't. It's easy to find; it's one of only two big rubber hoses that connect the engine and radiator, and the only one easier to get to from underneath.

Plastic can get fragile with time and heat. It always tempts me to buy a bolt of the same size and with the exact same threads, wrap some Teflon tape around the threads, and install that.

Check the threads by holding the threads of the plug and the bolt you're thinking of replacing it with against each other and making sure they all line up. Did that make sense? A picture's worth a thousand words, but I don't have one. Your parts store should be able to help you make sure the bolt has the same threads as the plastic thing, if you decide it isn't trustworthy any more.

And if you do reuse the plastic thingie, repeat after me while reinstalling it: I can break this thing with my little finger. I can break this thing with my little finger. I can break this thing with my little finger...

Because once you put the wrench on it, you really can.

[Anti Federalist]

Why are you changing the coolant?

Modern coolant, as long as it tests normal and has not been contaminated, it is usually good for the life of the engine.

Are you having other issues that you are trying to fix with a coolant change?

[Suzu]

Why are you changing the coolant?

Modern coolant, as long as it tests normal and has not been contaminated, it is usually good for the life of the engine.

Are you having other issues that you are trying to fix with a coolant change?

Well. heck, I thought you had to change it from time to time because it gets gunky. You're the first person I've ever heard say otherwise.

No real issues, except it's time for a new thermostat, and I figured it was also time for a change of the coolant. It hasn't been done for a decade or two.

[FindLiberty]

CONSIDER potential chemistry complications depends on the vehicle year: EXPENSIVE Toyota "pink" pre-diluted (or concentrate version expecting 50% with distilled water for older models), may be required for optimum compatibility with system metals and the important seal on the thermostat!

IDK what the best reasonable choices, (Toyota brand or aftermarket version) better read up on it/decide how many years you expect it to serve w/o troubles.

\there are two drain plugs on the engine block. Tricky to estimate how much replacement w/o flush if older version (or if aftermarket) requires dilution.

[acptulsa]

AF is right, but it has more to do with modern engines than modern coolants. Toyota stuck with cast iron blocks longer than most, and most of that 'gunk' is rust from iron engines. If the coolant you've gotten out is more brown than green, you're doing the right thing.

Thermostats have gotten tricky. I don't know if yours has a flat paper gasket or a more rope-like rubber ring. Either way, carefully clean the surfaces of the engine block and thermostat housing without scratching them. If you have flat surfaces, life is good. Use gasket sealer, but don't overdo it. Sealer on one side of the gasket is proper, but if the van is old it's hard to get the surfaces perfectly clean, so cheat and seal both sides.

The new gaskets aren't helped much by sealer. Get the surfaces very clean without scratching them, get the cleaner off (isopropyl alcohol cleans well and wipes/evaporates off well) and install it dry.

If that leaks, try slathering silicone sealant all over it and putting it back on. Good luck!

Be careful to read the label on the coolant. The pre-mix is cheaper per gallon, but a gallon is all you get. The normal stuff is about 40% more per gallon, but you add a gallon of water and get two gallons. Do add water if you get the normal stuff--it doesn't absorb and release the heat well enough without the water mixed in.

[Suzu]

CONSIDER potential chemistry complications depends on the vehicle year: EXPENSIVE Toyota "pink" pre-diluted (or concentrate version expecting 50% with distilled water for older models), may be required for optimum compatibility with system metals and the important seal on the thermostat!

IDK what the best reasonable choices, (Toyota brand or aftermarket version) better read up on it/decide how many years you expect it to serve w/o troubles.

\there are two drain plugs on the engine block. Tricky to estimate how much replacement w/o flush if older version (or if aftermarket) requires dilution.

I have utterly failed to understand what you wrote. Sorry... The car is 29 years old and the coolant is bright green, 50% water.

[acptulsa]

I have utterly failed to understand what you wrote. Sorry... The car is 29 years old and the coolant is bright green, 50% water.

Ah, A series four. Don't worry about what he said, he's talking about newer engines. You're doing the right thing getting the coolant out. I think those are the older, easier thermostat gaskets.

[Anti Federalist]

I have utterly failed to understand what you wrote. Sorry... The car is 29 years old and the coolant is bright green, 50% water.

If it's that old, with standard green coolant, yeah, you're doing right, especially if a service item (thermostat) is involved.

Flush it out as best you can and refill with 50/50 green coolant mix.

Make sure it gets fully up to operating temp before calling it full.

In other words, make sure the thermostat is fully open, and coolant flowing, and the radiator full, before you put the cap back on.

[acptulsa]

Right. And I don't envy you working on that engine up under the front seat.

But mostly, get out there at dawn and beat the heat. In other words, go to bed!

[Anti Federalist]

AF is right, but it has more to do with modern engines than modern coolants. Toyota stuck with cast iron blocks longer than most, and most of that 'gunk' is rust from iron engines. If the coolant you've gotten out is more brown than green, you're doing the right thing.

Thermostats have gotten tricky. I don't know if yours has a flat paper gasket or a more rope-like rubber ring. Either way, carefully clean the surfaces of the engine block and thermostat housing without scratching them. If you have flat surfaces, life is good. Use gasket sealer, but don't overdo it. Sealer on one side of the gasket is proper, but if the van is old it's hard to get the surfaces perfectly clean, so cheat and seal both sides.

The new gaskets aren't helped much by sealer. Get the surfaces very clean without scratching them, get the cleaner off (isopropyl alcohol cleans well and wipes/evaporates off well) and install it dry.

If that leaks, try slathering silicone sealant all over it and putting it back on. Good luck!

Be careful to read the label on the coolant. The pre-mix is cheaper per gallon, but a gallon is all you get. The normal stuff is about 40% more per gallon, but you add a gallon of water and get two gallons. Do add water if you get the normal stuff--it doesn't absorb and release the heat well enough without the water mixed in.

Oh, and to add to this, make sure you put it the right way.

Some makes, it is possible to put them in backwards.

Here's a generic view:



The pointy end without the spring faces toward the radiator hose and radiator.

[FindLiberty]

...good points - right side up too!

Yea, that 29 year old model does not "require" either crazy expensive
PINK Toyota coolant versions to maintain optimum performance and life.

No worries there - probably all brass construction! Distilled water keeps
the mineral deposits from plugging the core passages, but at 30 years
it's either ok or not at this point. Green or florescent yellow juice is good.

Newer ones are a little fussy:

The science is inside the passages of a new Toyota and it all gets spoiled
if accidentally filled up with traditional green juice; doing that will forever
diminish heat transfer due to a tiny bit of subtle surface corrosion inside
the radiator and heater cores and/or damage their tricky plastic end cap
seals. Tricky aluminum/plastic combination points are all just itching to leak.

The seal I mentioned is inside the thermostat (not the gasket).
IDK what combination of brands of thermostat and coolant are
best matched to preserve that tiny piston seal, but if it breaks
down, that thermostat will fail to build up enough pressure to
open up as the temperature rises... It may be just fine, or you'll
find out in a year or two if the engine starts overheating (even
in cold winter weather) and you face frequent replacement
of the thermostat every couple years. A crap-brand thermostat
that fails in 15 months is something I try to avoid. My Toyota
OEM thermostats have worked fine for 15+ and 25+ years...

It's a strange but effective kitchen experiment boiling water
with several suspect thermostats simmering away, some not
opening properly as the water slowly reaches their particular
design temperatures... been there, done that. lol

[Suzu]

I don't expect to be able to afford to keep repairing this van much longer so I didn't bother with the OE thermostat. If I get another year out of the car it will be worth it. Even if it holds up mechanically, the rust is taking over. I knew when I bought it brand new in 1987 that this would be my last car.

[DaninPA]

Why are you changing the coolant?

Modern coolant, as long as it tests normal and has not been contaminated, it is usually good for the life of the engine.

Is this true for a 2005 Nissan?

[acptulsa]

Is this true for a 2005 Nissan?

It's true of ethylene glycol anti-freeze/coolant, and always has been. The reason they make more of a point about it these days is the main thing that contaminates coolant is rust. The auto industry is increasingly switching from cast iron engine components, which rust, to aluminum alloy, which does not rust. Other things can contaminate it too, and more of those are also being eliminated from cooling system construction in recent decades.

In 2005 Nissan produced a variety of engines, some of which had cast iron blocks and some of which had aluminum blocks. If you're too secretive to even tell us if your Nissan is a car or a truck, you get to do your own research from there...

By the way, AF is not wrong when he talks about 'modern coolants', as they have rust inhibitors added which can allow them to prevent oxidation in iron engines--thus preventing their own contamination. So, if you're sure the coolant never got watered down, you're probably fine either way.

[ChristianAnarchist]

And I don't buy this crap about needing "pink" coolant in any car. I think they are only doing it because of "environmental concerns". While I am concerned about the environment as well, I doubt that cars today are "incompatible" with the green stuff. That's probably a scare tactic to get people to but the more expensive stuff. I don't think it's a good idea to mix the two. If you were doing a service that required draining all the coolant and wanted to replace the pink stuff with the green stuff I very much doubt there would be any problem. Metal is not likely to react to ethylene glycol (active ingredient used in the green stuff) and indeed, it really is not that bad for the environment (used to de-ice aircraft). The only other parts of an automobile to come in contact with it would be rubber in the hoses and gasket materials. These items have long been formulated to be compatible with ethylene glycol...

[acptulsa]

A conspiracy theory in a thread about changing coolant.

That's RPF for ya.

I'm not saying you're wrong, CA. Totally feasible.

[JK/SEA]

you'll never get all all that coolant out just by draining radiator. The engine has water jackets that keep coolant from getting completely out. If you're going to do it, do it right.

[acptulsa]

Well? We don't get a progress report?

[Semper Vigilans]

Any time you change coolant in a car, use distiilled water, and whatever coolant in a 50/50 mix as recommended by the manufacturer.

Unless it's a pre-2000 GM engine and is less than 75,000, then convert to the green stuff and keep it flushed every year...

[Suzu]

Well? We don't get a progress report?

I'm having trouble removing the old thermostat. I need a longer socket extension. May pick one up today. Also, the box that I thought had the new thermostat in it turned out to be empty. It was in the car for over a year.... I must have taken the thermostat and put it in a "safe place" where it would be "easy to find". If it doesn't turn up soon, I suppose I'll have to buy another.

[ChristianAnarchist]

I'm having trouble removing the old thermostat. I need a longer socket extension. May pick one up today. Also, the box that I thought had the new thermostat in it turned out to be empty. It was in the car for over a year.... I must have taken the thermostat and put it in a "safe place" where it would be "easy to find". If it doesn't turn up soon, I suppose I'll have to buy another.

Damn I hate it when that happens. There are times I'll take something and move it from a place it was for years to another place where "I'll be able to find it" and of course, I can't find it...