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The mkiv Supra Owners Club

Coolant loss


psymon

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Yes ive used the search......

 

Basicaly I have installled an new Koyo rad, and aftermarket coolant bottle. I have been losing coolant through the expansion bottle. Read the forum and have replaced my rad cap with new....

 

I have just run the car for 25 mins, temps are at only half way, fine thats great. But the expansion bottle did lose a bit of coolant.

 

So, have I overfilled the small expansion bottle. Is there a rule of thumb for this level, if you know what I mean. Do we go my the level indicator on this or do we have to make our own level mark.

 

car is not over heating, but can't go topping up every coule of days... I will be running the car tonight , but would like your thoughts

Would a different thermosat be required.

I have an FMIC , this is why i bought a new beefier rad

Thanks

Simon

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Guys,,

Ok went to work last night, 32 mile round trip.... have just checked the expansion bottle and its empty again.... Im running out of fourlife and I still have a problem.

 

I can only presume it maybe a a leak on one of the hoses I disconnected. I its not this what else can I check......

 

Getting pissed off now as I don't know why this is happening

 

cheers

Simon

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Its pretty obvious when coolant leaks due to the residue it leaves, if there is no residue showing then you may have simply had an air lock in it, did you turn the heaters on when you were filling the coolant?

 

If not, then the matrix was probably empty until you turned the heaters on in which case, the water from the tank has dissapeared into the matrix.

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I have Koyo so its all metal...... I have a smaller expansion tank, located next to battery...... mini tank, not alloy

 

I went for a blast today with bout a cm of water in the expansion tank, this is what was left from last night. Thought was, if its not holding pressure then the tank would overflow again right ?

 

Came back, and expansion tank was bout 2/5 full, left car running a further 15 mins, and no more coolant came out to top bottle up so level was stable. Temps are rock steady at half way.

 

Maybe I am overfilling the smaller expansion bottle as its alot smaller than the original.... ?

 

I did tighten up the drain plug by 1 turn too.

 

 

Im thinking maybe I only need about a 1/3 in there and how it goes

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If the system is working OK you shouldn't need to add or subtract water.

The 'cold' level in the tank should always be the same, and the rad should always be full to the brim (only check that cold, obviously!)

 

Don't overfill, the tank needs to have a minimum volume of 'head'.

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Guys

Im still losing coolant from the expansion bottle ?

 

Koyo rad installed.

New TRD rad cap (thought this would cure problem)

Smaller expansion bottle located next to battery

 

Even on short journeys 20 miles it leaks out of bottle even though a small amount. I haven't topped up for 2 days and the rad is still full to the brim.

 

Is it possible my expansion bottle is to small for the volume thats coming out.

 

Would an air lock cause this.

The reason i ask this is that I only put 10 litres in and the stock rad holds 9 ish. Surely the volume would more. I have tried the net but no-one gives figures.

 

Car is not overheating although goes up to 2/3 before the stat opens. Im running with a fmic

 

Any help much appreciated, and thanks for the help so far guys

 

Si

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Could I also add this to the thread as it is a similar topic:

 

When is it best to fill the expansion tank?

 

Engine hot or cold?

On or off?

Where should the level be in the expansion tank when the car is off and cold?

What fluid should put in it? Water/anti freeze?

 

The reason I ask is because I read this thread before I went to work on my car earlier to find my expansion bottle was on the low marker. Took the rad cap off and it is full up to the cap in there. The engine was cold and not been used for over 24 hours.

 

Thanks

 

(and sorry for the small hijack)

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Guys ran the car today and bleed radiator, bit of air came out but not much.

Topped up expansion bottle to a minimum and have just came to work. And you guessed it some coolant on the floor.

 

As stated I have a new koyo rad, new cap and a smaller expansion bottle.

 

My only theory now, is the expansion bottle is too small to hold the amount of coolant of the header in the rad. It is nearly twice the width of std rad....

 

Is this feasable ?

 

If not Im at loss, i don't know what else it could be.....

 

Si

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Ok finally found my problem..... After much scratching of head and headaches.

 

A Koyo radiator gives an extra 30% volume over stock. This equates to an extra 2.85 litres of fluid. This topped off with an FMIC and a smaller expansion bottle, there was basically to much coolant for the smaller bottle to handle.

 

I managed to wedge my old stock expansion bottle back and its been fine. It just don't look pretty , wedged in. So I can either find a small expansion bottle which is deeper and has more volume. Leave the original wegded in ( not relocating it to under light) or, is it possible to link 2 of the smaller expansion bottles together as I can make both of them fit. Thus once the first is full it starts filling the second. In theory this sounds good, but not sure when the coolant coolers if all of it will be sucked back.

 

So a lesson learned, Koyo rad and small expansion bottle is a no go.

 

Its cost me the price of a brand new smaller expansion bottle and a new rad cap to find out an a few hours checking for leaks.

 

Any comments on my twin bottle idea please

 

Cheers

Si

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