Water Reservoir / Engine Coolant Tank

[Deadmanwalking]

Hi.

When I fill my water reservoir to the maximum level, the water level drops to the minimum level over a 4 week period, car has travelled 1,000 miles during that time. Does this sound about right to you?

Car is a 2006 with 20,000 on the clock. No smoke from the exhaust, oil looks fine if this helps.

[Anonymous]

Nope,mine hasnt lost any in 5 years of ownership.

[JudoKilli]

Mine lost it's entire contents, but that was only because the radiator blew on a long journey. Before that, and since replacing the radiator, it's been at a very constant level.

[2 of the left]

Check your rad and your hoses for leaks!! but don't fill it with water!! -Use coolant

[Deadmanwalking]

When on the minimum level the water looked nice and pink...............so I filled it with water.  s:( s:(  

Should I try *************** or just top up with this coolant that you so highly speak of  s:D s:D    s:D s:D    s:D s:D   Is it just an antifreeze thing or will the water cause other issues too?

[kentsmudger]

You won't get the water out by syphoning, and it will have just diluted your coolant a bit, I believe there is 10 litres in the system, so is hopefully still mostly coolant at the moment - Top up with coolant if it needs it but find the leak!

Quite likely to be the rad - They do corrode and it may well be oozing where you can't see it, under the front plastics. It will only get worse, so investigate before it drops a lot  of coolant and does some more serious damage.

Replacing the rad is not too tough and you can drain the system and fill with proper coolant at the same time.

Some pics that may help - Here

[SteveJ]

Once it has dropped to the min mark, does it continue to drop? I suspect not - there are a number of posts on here about coolant levels and the consensus is each car has it's own preffered level and no matter how much you top it up, it just blows the excess out of the overflow.

My car has been sat at the minimum level (when cold) for 4 years now with absolutely no adverse effect. Provided there is at least enough coolant in the bottle when cold to cover the bottom hose connection then leave it alone.

[Deadmanwalking]

I purchased the car around one month ago. Before buying, I told the garage to take the car to a main Toyota franchise dealership and to get the car serviced and inspected there, which they did. This gave me the chance to speak with Toyota direct and obtain an unbiased view on the cars health, it came up trumps.

Anyway, I ASSUME that Toyota filled the reservoir to MAX (can't confirm as I never looked at it at the time) but one month later on it sat at 3mm's just above MIN level having now actually looked at levels.

So I topped it up 10 days ago and accidently overfilled to just above MAX. Hardly driven the car due to snow since 10 days ago. So in the past 10 days I have driven say 50 miles and now the coolant level has dropped from 3mm's over MAX to 3 mm's under MAX.

PLAN? Keep an eye on the coolant level until it gets just under MIN level. At that point call garage I guess. I think I am having premature kittens in all honesty but wanted your views to help access just how much I should pre-panic.  s:D s:D    s:D s:D    s:D s:D  

Kentsmudger thanks for supplying the link.
SteveJ thanks for info re each car reservoir finding preferred levels. I ran searches but came up with little info.

Thanks to all contributors.

[kentsmudger]

Reservoir does go up and down a bit with heat and use, 3mm is not much to worry about - Make sure it does not drop below min, and only top up with correct coolant if needed.

Sounds like you do not have a major issue    s:D s:D

[Deadmanwalking]

Thanks

correct coolant? Suggestions please.  s:D s:D    s:D s:D    s:D s:D    s:D s:D    s:D s:D

YES.............I really am that rubbish around cars.  s:? :? s:?

[Treboeth]

Mr.T red coolant or some have used Halfrauds coolant.

[onion86]

Halfords professional coolant is fine it's about £25 for 5 litres, if you want to be 'safe' use the Mr T red stuff though but you probably shouldn't mix so have the drain the whole system.  I used it when I had a drippy rad, losing about 1/2 litre every couple of weeks, since I replaced the rad about a year ago I never had to top it up until I re-piped the pipes after taking the turbo out last month  s:) s:)

[frogger]

The fluid volume itself will vary a bit due to thermal expansion; 220ml over 11ltrs as an approximation at full operating temp.

Then the volume of the waterways in the radiator, hoses, block, everywhere will also vary depending on temp, ambient temp, temp of fluid, affect of air cooling, proportion of antifreeze, type of antifreeze, surface tension inhibitors (wetterwater for example), time at temperature, etc.. etc... etc...

To summarise: Theres a few variables at work! If its routinely loosing its level and leaking then worry, otherwise don't worry about the fluctuations. It's normal.

[redarrow]

If this was a mgf ill say head gasket gone, but it a Toyota so i am sitting here and awaiting the end result.

best regards redarrow.

very interesting.

buy now if it a mgf it be pressure tested and not driven at all with loss of coolant the head can go pop.

you say it been sitting in the cold, are you sure that the coolant was bleed properly before you got the car?

according to loads of posts the head does go but usually the radiator is first.

i would defendant get it fixed via the person you buy from because if it a coolant head  related problem that real money.

get the car pressure tested from the garage you got that car, that my advise to be really sure the heads ok.

sorry i no that sounds scary but true very expensive head replacement.

I remember a time i was told because my coolant was all running out all the time in the end i  had water in the back car just encase, i was quoted £900 ahahahha yee £900 full skim new head the lot, but guess what i found it to be the hose on the reservoir bottle.
and that was rover them self what divs, it cost me 29p for one jubilee clip on the hose.

what you need to pressure test the radiator from the reservoir bottle to see where the leak is or no there one.
http://www.ebay.co.uk/itm/Detector-Radiator-Cooling-System-Pressure-Tester-Set-/120712181989?pt=LH_DefaultDomain_3&hash=item1c1b01b8e5
if you get one please ask there a Toyota fitments.

you can also make one, just use a bike pump with a pressure gauge ,then a reservoir cap for the car, then add a bike valve to the cap, screw it to the car reservoir, pump the gauge up keep it to a preferred number on the gauge,if it goes down after 2 minutes there a pipe leak in the system now find it. (all for around £15 home made)

My coolant never moved, had the car around 7 months, no problems with that part of the car fingers cross .

[Anonymous]

It won't be the head gasket,I have only heard of one of them going on an MR2 and that was after the car emptied all its coolant system and steam was coming out of the engine cover.

[redarrow]

so it pipes and radiator a leek.

[Wabbitkilla]

It would be worth removing the frunk plastics to take a look at the radiator - any pink deposits mean that it's starting to leak.

[redarrow]

Could be the coolant pipes there self underneath, are they stainless steel on a mr2.

as what i can see nope, another mod can be made then.

best regards redarrow.

[Chris H]

Dont mean to divert away from this thread,but,redarrow,as a previous owner of an
mgf,you need to do away from that car and concentrate on the "2".....you are becoming
"mgf tunnel vision".......dont take offence.........  s:roll: :roll: s:roll:

[Anonymous]

I have a 200. Spyder with120,000 miles on it.  I had never had fluid loss from my reservoir  , had low fluid light come on.  Filled it with coolant, replace the cap on reservoir, no further problem.  Caps wear out, allow fluid past overflow.  Cheap fix, even if not problem, worth doing anyway.   s:wink: :wink: s:wink:

[Deadmanwalking]

Strangest thing has happened in that the replenished water (put in a couple of weeks ago) which quickly dropped from 3mm's above to 3mm's below the MAX line has now returned back to just above the MAX line.

Now that the snow has gone I am using the car once more and have done perhaps 300 miles since topping up. I guess that the cold weather is causing the water to contract? Water has not frozen though unless it freezes deep down in the reservoir tank as its remaining in liquid form on the surface.

To be safe should I ******************  and replace with coolant do you think?

cheers

[Dyn-Evo]

Little bit of a hijack here, but still coolant-level related...!   s:wink: :wink: s:wink:  

Can I just ask how much coolant a stock MK3 system expands by when it is hot?

Assuming the level is at "Max" when cold, how much above that will the level be (immediately) after a 100 mile run....?

Cheers!

[AckersMR2]

Strangest thing has happened in that the replenished water (put in a couple of weeks ago) which quickly dropped from 3mm's above to 3mm's below the MAX line has now returned back to just above the MAX line.

Now that the snow has gone I am using the car once more and have done perhaps 300 miles since topping up. I guess that the cold weather is causing the water to contract? Water has not frozen though unless it freezes deep down in the reservoir tank as its remaining in liquid form on the surface.

To be safe should I syphon out and replace with coolant do you think?

cheers

Mine was half way between MAX and MIN when cold, so I topped it up to MAX about a week or so ago and when I checked it at the weekend, again when cold the level is now about 10mm above the MAX line?
I'm no mechanic but thinking about it now doesn't the cars heating system get its heat from the engines coolant system? In which case depending on what setting the cars heater is on will affect slightly the level in the coolants expansion tank? I.E. heater on coolant level lower, heater off coolant level higher?
I'm sure some technically more informed than me will confirm/put me right on this?

[Deadmanwalking]

Quick UPDATE as I still need an explanation please.

Checked the coolant this evening and the coolant level had returned to MIN, groan. The car is parked on a slight incline so I figured I would drive home and check again on a flat surface.

So I arrive home 60 mins later and leave the car for one hour. Checked the coolant level and it was still on MIN. Felt the reservoir bottle, which was slightly warm, and thought.........OK lets remove the lid, it's safe.

As I unscrewed the lid there was a sharp loud liquid exploding sort of noise coming from inside the bottle. It was over in a flash and having now removed the lid, the water level had returned to MAX.   s:? :? s:?    s:? :? s:?    s:? :? s:?  

Has someone got a full explanation for this please?

[kentsmudger]

Hot water expands - cold contracts. In a sealed system like ours the expansion increases the pressure quite a lot (preventing it reaching the boil) . Rubber hoses can expand a bit under pressure and the air in the top of the system expands too, pushing down on the water.

The water gets shunted around the radiator or not depending on the thermostat temp and around the heater matrix dependant on the controls.

The upshot of all this is that the level in the water reservoir (or expansion tank) will rise and fall in different conditions and as long as it stays between Max and Min, you have very little to worry about.

Also, as you have discovered, you must take care removing the cap from a warm bottle, as the pressure is high and the water within the engine block can still be quite hot. As the pressure is released, the water can boil quite suddenly.

Keep an eye on it, and don't let it drop below Min - Top up only with proper fluid if needed - If it gets above Max or under too much pressure I believe it will vent, so no point in over-filling.

If the level is not continuing to drop past Min, and you have found no dripping, I still don't think you have a major issue.