(Home) Bubbles in water & final level

I refilled with water after replacing the turbo and I have the engine running & the cap off to allow air pockets to get out. However someone said the air bubbles I see might be due to blown gasket.
The oil doesn't look contaminated with water and the water doesn't look contaminated with oil.
What do you all think?
Also do you all get the level of water to remain at the top of the neck after a drive my level seem to be consistently at about the level of the thermostat.

- (#8606) Peter Dawson, 20 May 03 3:24

If you have filled your system with only water, ie no antifreeze, And you are running the engine with the cap off, the boiling point of the water will be 100°C and the bubbles in your system are what you would see in a saucepan of boiling water. This is the saturated air that has been released from the water as it nears boiling point.

If you haven’t already, Add some antifreeze, replace the radiator cap, and run it gently for a while. Make sure you check the level of coolant in the expansion tank, and when the system is cold, the filler neck. Do this every day until you see the coolant level in the filler neck stabilise.
If you have used tap water, the air that water has in it will be released over time, and this is why you need to keep a close eye on it.

By the way the thermostat is on the bottom end of the engine. If your coolant drops to this level, you have a very big leak, and to top up the neck would require quite a few Litres of water!

Hope that helps
dave Bright
- (#8607) dave Bright, 20 May 03 3:52

I'm assuming there is still some antifreeze left in the system. The bubbles occur at cold.
Hmmm...I thought it was the thermostat but I am refering to the 'lump' at the other end of the small diameter pipe from the cap...the 'lump' has two electrical push-on connectors (temperature sensors?).
In all the time I've had the Masterace the level always appear to stabilise at around the vicinity of this 'lump' (guessing by the amount I put in each time - very small) - what is this 'lump' so I can call it by its proper name?!

- (#8608) Peter Dawson, 20 May 03 4:07

Level.
The level seems a little low, but if its always stabilised there then it may be ok. It would be worth checking the operation of the radiator cap and expansion tank just in case though. Your cap may not be allowing the coolant to return when it cools down after a run.

Bubbles.
When did you last change your coolant? What colour is it? Is it clear, wishy washy, or strong in colour?
Are the bubbles small, and gentle in the filler neck, or are they big, causing violent eruptions?

- (#8609) dave Bright, 20 May 03 4:30

Toyota call it "outlet" , the thermostat housing is called, wait for it, "inlet".

- (#8610) Clive, 20 May 03 4:31

The vehicle has had a history of water expulsion from the expansion bottle over the past two years when I've gone fast for around half an hour. Toyota have looked at it - pressure test, flush out & replace coolant - with no effect. I have read on ACE Answers it could be the fan, head gasket or the radiator cap - I have now replaced the radiator cap but have not tested it. I haven't tried testing the fan I am not confident I know what to do but I'll revisit ACE Answers to try and find out but I don't fancy using my wife's hairdryer - I'll get in trouble.

Level
how do I check operation of cap & expansion tank?

Bubbles
Coolant changed within last two years. It's mainly clear with very slight hint of green or blue.
The bubbles are of same size of pipe diameter or half size. The bubbles are fairly gentle. They're not continuous. I've just added a bit of water, revving raises the level and the water returns to a lower level so I top up - it happens a couple of times then stabilises. I bubbles now happen intermittently.

- (#8611) Peter Dawson, 20 May 03 5:29

“The vehicle has had a history of water expulsion from the expansion bottle over the past two years”

Ok lets try to sort this before anything expensive happens.

First Change the coolant. Anything up to 50% water and 50% antifreeze will do.
Drain the old coolant. Fill with clean water and a chemical flushing agent, run the engine at temperature for 10 minutes. Allow to cool, drain system. fill the system with clean water and run for 10 minutes. Drain the system again. Get a 5Litre bottle of antifreeze. Pour half of it into your system SLOWLY. Add the same amount of water to the system. Top up the bottle of antifreeze with water, and slowly add as much as you can. This maintains a 50/50 concentration of antifreeze.
Gently run the engine until its up to temperature and the thermostat opens. Also turn both heaters to hot, and turn on them on.

Next check the operation of the radiator cap.
Never remove the radiator cap from a hot engine. Severe scalding may result.
Start with a cold engine.
Check the level of coolant in the filler neck, and top off as necessary.
Check the level of coolant in the expansion tank is between the high and low marks when cold, and place a mark on the side of the tank.
Start the engine and allow the temperature to reach its normal position.
Check the level of coolant in the expansion bottle when Hot. It should have risen slightly. Now place a mark on the side of the tank.
Allow the engine to cool off again, and check that the level in the expansion tank drops from the Hot mark to near the cold mark.
A couple of hours or more is required to allow the coolant to cool off enough to suck back some of the coolant in the expansion bottle. The longer time you allow, the more the level drops.
If the level does not drop from the hot mark, then the radiator cap is faulty, or the hoses are leaking, or the tube in the tank has become disconnected.
Don’t be tempted to check the expansion bottle tubes by sucking on them. Antifreeze is poison., even a small amount will make you very ill.

Bubbles
small amount of bubbles is ok

- (#8612) dave Bright, 20 May 03 5:59

Just a quick note Peter,
Before you start filling up with the coolant mix, change the thermostat, and thermostat o-ring seal. This could be one of the causes of your coolant loss. Use proper Toyota thermostat 30mm opening and seal mind, phone your local dealer with the details from your vin plate and they will send the right parts.

- (#8613) dave Bright, 20 May 03 6:46

Thanks Dave, I forgot to say that the Toyota garage changed the thermostat as well when they did the work.
I'm off on my trip tomorrow so may not have time to do everything you say. But thanks for all the notes - I will certainly do it on my return.

- (#8614) Peter Dawson, 20 May 03 6:58

Peter.
“mainly clear with very slight hint of green or blue” sounds like to little antifreeze to me. This is what increases the boiling point of the coolant, so if you are going off in your Masterace tomorrow, drain some water off and poor more antifreeze into it. 2-3 litres should be enough. This and your new rad cap may just do the trick. good luck.

- (#8615) dave Bright, 20 May 03 7:08

Thanks for that extra bit of advice - will report back in a while.

- (#8616) Peter Dawson, 20 May 03 13:12

Just to report that I took the townace onto the mainland and in a week travelled around 500km often a couple of hours at a time at around 70mph - the temp needle STAYED BELOW normal the entire time (previously expelled water after 20-30 minutes above 60mph).

I didn't have time to drain the water and put in extra anti-freeze - naughty boy! - also I didn't want to waste it expelling out the expansion tank as before.

So the answer to my expellation problem would appear to be simply the replacement of the radiator cap. Interestingly the lack of anti-freeze did not appear to be a contributory factor.

The other thing is the level in the expansion tank rose after a drive i.e. not returning to the rest of the system. I thought the tube entering the tank was possibly too long perhaps touching the base of the tank so I replaced with a slightly shorter tube and hey, presto the level was dramatically lower after the next drive.

I think I am losing a little bit of water so I am looking forward to changing the coolant, adding anti-freeze and seeing what happens. I'll have the opportunity of taking it out for a good run in a couple of weeks.
- (#8903) Peter Dawson, 3 Jun 03 7:04

Hi Peter
Glad to hear that your cooling system is much improved, and thanks for the crucial “guess what? I finally cracked it” post. All to often this is the missing link on Ace Answers.

“Interestingly the lack of anti-freeze did not appear to be a contributory factor.”
Pure water boils at 100°C. Put it under 15psi and the boiling point increases to 120°C.
50% antifreeze only increases the boiling point by 8 or 9°C at any pressure, so the main thing is a 15psi radiator cap, and that seems to have done the trick. When you do change the antifreeze though, change the thermostat and o-ring seal with proper Toyota ones as well.

A small amount of water loss could well be the water venting the saturated air at high temps, so keep an eye on it for a while.

If you have an automatic gearbox, it would be a good idea to have a specialist check the condition of the ATF. As this has been an on going problem for a few years, the Successive and excessive heat cycles may have cooked the oil. Smells like burnt toast I’m lead to believe.

dave Bright

- (#8904) dave Bright, 3 Jun 03 8:09

Dave
Thanks for your comments and additional note about the ATF.

Why are you recommending the thermostat to be changed?Is it usual practice to change the thermostat when changing the antifreeze? I had only intended to change it if there were any major problems or the temperature needle was adrift of normal - both of which do not now appear to be present.

- (#8905) Peter Dawson, 4 Jun 03 6:23

Peter
The cooling system of the Aces is finely balanced, and it only takes a small deficiency to unbalance it to the point of overheating. As it sounds like the radiator cap was the cause all along, and Toyota have changed the thermostat recently, it may not need replacing. Its still a good idea to remove the thermostat and check it, so its best to have a spare one just in case you find that there is a problem.

I recently removed my working thermostat when I changed my coolant, and found the central barrel had a lot of new and shiny scratch marks on it. A sure sign that it was nearing the point of failure, and I also found that it appeared to be incorrectly fitted. The thermostat was not inside the o-ring seal.

Hope that helps
dave Bright

- (#8906) dave Bright, 4 Jun 03 6:59

I see. Thanks for your help.

- (#8907) Peter Dawson, 4 Jun 03 10:46