I topped the coolant up last week and on checking it today, the level had dropped about 1 inch in the expansion tank to the minimum range fill level. No obvious coolant loss, no overheating and car running fine.

I actually suspect evaporation/ escape via the bleed screw.

The car has probably covered 500 or 600 miles in the week since I topped the coolant up. Is this an acceptable 'loss' of coolant?

Thanks

Probably not. you could have a small hole in your rad which evaporates so not leaving a trace. It will only get worse. Mine had a small loss at first, then got more and more until I replaced the rad. all good now!

I've probably put less than a mug full in mine over 3 years. If that. Only 15k miles though......

If it's not lost any before you could have a small leak started.

I'd keep an eye on it...... 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport

Thanks for the replies. They are all new radiators. I've had foibles with the bleed screw seal (o rings do little and so I use PTFE Teflon tape to seal it). The screw tends to work it's way less than air tight at times. I'm keeping an eye on it but just needed to know if small losses were within acceptable limits.

A coolant system is a sealed system therefore any noticeable coolant loss is unacceptable in the timescales you describe IMHO.

As it sounds as though work has been done on you system check you don't have an air-lock somewhere and that it is bled well - don't forget, if the bleed screw leaks under pressure, when the system cools it will then leak air back in causing a problem.

Air in the cooling system other than the designed volume in the header, creates excessive expansion within the system which then pump more water out at full temp which in turn creates a vacuum when cold sucking air in through any path it can find including the water pump seals which are designed to hold pressure in - not out.

Also worth checking the level you describe isn't your cars own level - if you don't top it up does it continue to drop or is that it?

Good luck and I hope you find a nice cheap solution

Temperature makes a big difference to the level in the expansion tank on the SC.

You need to fill it to Max when it is stone cold, then check again when stone cold - there was a TSB issued about this.

Bottom line, it shouldn't use / loose any coolant. Stolen / Gone: 2006MY Supercharged LPG Autobiography - Zambezi Silver with Sand/Jet/Jet Oxford Leather.....

I had exactly the same symptoms on my 4.4 AJV8 up until this summer - cured with a new radiator.
The original had a barely perceptible split on the bottom inner edge -

 Where do you go after one of these . . . ?

Ryan, I agree with Colin, the level in the header tank is very sensitive to temperature, if the engine is slightly warm it will read high, then the next time you check it it may be stone cold, so will appear low. The level in mine fluctuates with temp, both engine and air temp.

So I advise to top up with engine cold in the morning, run it and then check a few days later in the morning again. And see if it has changed, it should lose zero coolant! There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
Fiat 500x 1.4 multiair Lounge 2015
2010 LR D4 Commercial 2.7 TDV6

I didn't know my car needed coolant

Never had any reason to top it up Got - 2017 SDV8 Autobiography in Loire Blue
Had- 2008 TDV8 Vogue SE in Java black
Had - 2007 S/C in Stornoway Grey

Never topped mine up in 4 years of ownership

If you do top it up and inadvertently put too much coolant in it will spit the excess out and should find its own level, so the next time you check it will possibly be lower than when you topped it up. Only top up if the light comes on

Thanks all. I just wondered if they lose a little over time and use.

I topped the car up last week when the engine was overnight stone cold. I checked the level today when the engine was overnight stone cold and having marked the level under the same circumstances last week, I noticed that it appeared to have dropped "about an inch" on the tank marker today.

There are 2 new radiators on the car. I get your points about settling and finding its own level.

Any coolant loss I've ever experienced with this car has been bleed screw related (not making a good enough seal). I'll monitor it and mention it to the garage when the car goes in this week.

I'm using about 1/2 litre every 1500 miles or so, no sign of a leak anywhere and this with a new radiator. Obviously coming out somewhere but yet to find it. Just to give some balance to the lucky ones who have a sealed system.

Have never had to top up my 1990 MX5 in 8 years  .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

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