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MG MGF Technical - Water Level

What is the correct level for the coolant in the expansion tank? The reason I ask is that everywhere says the seam line on the tank but my level is always about one inch lower,the fluid is just in the bottom of the tank if I top it up after a short drive it always reverts to the lower level.When it is at the lower level it stays like this for evermore. Any Idea's
Thanks
Simon
Simon Kaye

Simon.
As far as I am aware that the correct level is the seam, why do you top up after a short run, are you losing coolant, a small leak from the tank just below the seam maybe.

When it's warm the level will rise, expansion, and drop back to the original, set, level when cooled down.

Shouldn't really need to top up unless you have a leak or faulty pressure cap.

Adrian
Adrian Clifford

I would say that if there is coolant in the expansion tank and it does not drop below the lower level that you mention then it is OK BUT do check it when hot as well as cold.

Warning though - do not take the cap off whilst hot as the pressure drop will cause the water to boil out and could scald you - just view the coolant through the opaque tank.
Ted Newman

The level is always the same when hot or cold, there seems to be no leaks and the system holds its pressure ok, so i asume the cap is working. I just top it up to the supposed correct level as a bit paranoid about driving around with low level.
Simon Kaye

Water level should be around 1cm higher in the bottle when hot, due to the greater presure in the coolant system!.
Mark.L

ditto what mark says,when hot mine is about 1cm above the line ,when cold it is below,however if i top up when cold to the line it will show a rise when hot to 2 _3cm above,but this only lasts for a short while although i have a new cap, it always settles to the same original level. Another point worth mentioning is that i have put a litre of water in over a two year period , where did it go in a sealed system,??? done 250 miles at the weekend and the level is the same as when set out,but i will bet my bottom dollar it will need a small amount in by xmas ??
m e johnson

sorry didn,t quite finish,as SIMON kays car it does seem to get to a level where if i don,t top up it stays the same,but this looks to low to me and so the trend continues , i,m sure i have read about this in the archives,and each car seems to settle to its own level, but do keep a check on it. hth mel...(non expert)
m e johnson

Normal level for my car is about half an inch below the seam line. If I put any more it spits it out and settles there for ever. It's been like that for eight years now without any problem. So, keep an eye on it and if it doesn't fall any further there is no point in topping it up all the time.

There are over 40 hose connections in the mgf cooling system so eventhough it is a sealed system, a few drops of coolant are bound to find there way out. I check all connections at least once a year and tighten up/ replace the clips as necessary.

Spyros Papageorghiou

Thanks for the help guys, it seems from what you have been saying this must just be the normal level for my car.
Simon Kaye

About an inch below the seam line is the minimum level (see http://www.mgf.ultimatemg.com/group2/common_problems/hgf_pages/HGF_prevention.htm) - so, so long as the level doesn't drop further, you'd don't have a problem.

It may be that the expansion cap pressure valve is starting to weaken, leaving you with the lower level - keep an eye on it (there may be some tell-tale crystaline deposits around the cap) and consider replacement (cheap!)
Rob Bell

My 8 month old TF coolant level has so far only needed a slight top up when it dropped a couple of mills below the seam.

Thing is the level remains the same hot or cold. Is this something to be concerned about? The car seems to run fine and so far touch wood no probs at all.

T Lupoli

In Theory the water level will rise slightly as the hot water expands and pushes against the air gap in the expansion bottle.

How much coolant are you loosing?.
Mark.L

Well none really. I topped up about 2mm's shortly after I bought the car and its been fine since. It just never seems to rise when its hot.
Tony L

This thread was discussed between 19/10/2005 and 23/10/2005

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