Coolant level dropping

[mission]

So yesterday I picked up my new van, a 2007 Peugeot Partner 1.6 petrol.
Didnt check the fluids and an hour later arriving home I checked everything and noticed the coolant level sitting just below the minimal mark. Filled it to the maximum mark and forgot about it.

This morning I checked again and now the level was again down to just below the minimum mark. Took the car for a drive and after things warmed up the level now sits arround half way (between minimum and maximum).

Is it normal for the level to drop and rise like this? 

I cant find a leak anywhere, the coolant looks green as its supposed to, no slush underneath the oilcap, no smoke from the exhaust, no overheating etc there isnt any sign of there being a problem but it does worry me a bit.

I did have the heater on full last night, could it be the coolant was low and now its filled the heatercore? Then I might need to add a little more coolant to top it off again.

[hawkeyefxr]

Apart from the obvious head gasket leak, it might have had an air lock in the system. Driving along may have caused this air lock to move on to the radiator causing the level to drop.
Is there vapour from the exhaust?

[mission]

Apart from the obvious head gasket leak, it might have had an air lock in the system. Driving along may have caused this air lock to move on to the radiator causing the level to drop.
Is there vapour from the exhaust?

No smoking coming from the exhaust. Also no oil in the coolant or coolant in the oil.
Will check again for any leaks, I really hope its not the gasket.

Also the coolantfillercap was impossible to get off, arent those things supposed to be tightend fairly loose?
I allready ordered a cap to be sure

[jj9]

When the engine is totally cold like after standing overnight check the coolant level, if it's below the MAX top it up to the level.
The following morning when the engine is cold check it again how does it read?

You need a base line to work from to establish if you are actually loosing coolant, doing the above will give you that.

.

[mission]

When the engine is totally cold like after standing overnight check the coolant level, if it's below the MAX top it up to the level.
The following morning when the engine is cold check it again how does it read?

You need a base line to work from to establish if you are actually loosing coolant, doing the above will give you that.

.

Thats a good idea, that will have to wait till tomorrow ofcourse but lets try

-Edit;

When a headgasket fails, doesnt that usually turn the radiator hoses rockhard? My hoses are fine, even when hot and with the engine running they remain soft.
Today I drove near 130 kilometers, and I lost track of how many times I pulled over and checked everything but the level now seems stable at about 2cm above minimum.

Will top things up tomorrow morning, I have a 300 kilometer family tip planned and lets see what happens

[jj9]

I've just re read my post and the advice I gave was was wrong.

The Max mark in theory should only be reached when the engine is hot and the coolant has expanded, when the engine is cold the level should be around the Min mark.

Often engines find their own level, Max & Min doesn't really matter as long as the level stays the same when cold.

Take note of the level when the engine is cold and as long as it's the same in a day or two's time all is well.

.

[hawkeyefxr]

Apart from the obvious head gasket leak, it might have had an air lock in the system. Driving along may have caused this air lock to move on to the radiator causing the level to drop.
Is there vapour from the exhaust?

No smoking coming from the exhaust. Also no oil in the coolant or coolant in the oil.
Will check again for any leaks, I really hope its not the gasket.

Also the coolantfillercap was impossible to get off, arent those things supposed to be tightend fairly loose?
I allready ordered a cap to be sure

yes could be the cap, if it leaks slightly the coolant could slowly boil off.

[mission]

I've just re read my post and the advice I gave was was wrong.

The Max mark in theory should only be reached when the engine is hot and the coolant has expanded, when the engine is cold the level should be around the Min mark.

Often engines find their own level, Max & Min doesn't really matter as long as the level stays the same when cold.

Take note of the level when the engine is cold and as long as it's the same in a day or two's time all is well.

.

Bugger, I only just read your comment. Oh well, this morning the level was the same as yesterday and I filled it up to the maximum mark.
Did quit a lot of driving today and so far its still at the maximum level. I dont need the car tomorrow so lets see what happens after sitting still for a day.

[Sol]

As JJ says the coolant expands when hot, hence the term expansion tank. As long as there is an air gap above the fluid it will be fine. If need be you can get some out when it's cold, to get the level nearer the min mark, or somewhere between min and max.

[mission]

As JJ says the coolant expands when hot, hence the term expansion tank. As long as there is an air gap above the fluid it will be fine. If need be you can get some out when it's cold, to get the level nearer the min mark, or somewhere between min and max.

Yeah it still has room to expand, so that should be fine. I just hope the level will remain steady, as the coolant cant just disapear it must be going somewhere