Losing coolant

[ayat]

Hi guys I'm getting really frustrated now with my coolant loss. It's been going on since I purchased the car and no one seems to be able to diagnose it. It seems to be going somewhere but I've never been able to see signs of where it's going. Will I be ok topping up with water for the time being, only concern is the winter temp. How dangerous is low coolant now we are in the winter months. Engine temp seems to be ok. I've given the car twice to well regarded independent (Ncb autokraft) they have pressure tested and have said there are no leaks, an replaced then cap twice. But still losing coolant? Any other areas that I could suggest. Ayat

[X5Sport]

How fast are you losing coolant? I'm assuming if there's no sign of a leak then the evidence is vanishing as steam.

Topping up with water only is definitely NOT a good idea. You will be weakening the mix and herefore the minimum temeperature you are protected down too, as well as losing the corrosion protection You are better off getting a large botle of coolant direct from a BMW Dealer (ideally but not vital) as then you know you have all the right corrosion inhibitors and will be maintaining the low temp protection.

The usual suspects for leaks are (if I remember correctly):
Pressure Cap (but they've changed that (twice!)
Expansion Tank - a known weakness, but should have been found by the pressure test.
Head Gasket - would usualy result in 'mayonaisse' like waste on the oil cap and in the oil itself if water gets into the oil.
Hose or Hose Joint - might only show when hot.
Radiator Matrix - should show the leak or ail the pressure test
Internal Heater - might pass a cold pressure test, fail when hot, and leave a smell of coolant in the car.
Cracked Block - unlikely considering what's been checked. This failure mode tends to be somewhat terminal and shows up quickly and clearly.

Do you know if the presure check was done hot or cold? If only cold, then a hot one needs doing too. I remember our workshop guys doing both with the system pump. I also remember them using a pressure guage to check the actual system pressure with the engine running. They used to do it on our Ford Granadas to see if the pressure cap was the issue, or if there was blowback into the system meaning the pressure cap was venting the overload to prevent a burst. Modern systems may work differently, but I still thought the expansion bottle cap was designed to vent excess pressure nd you would get steam and coolant loss.

[shadrack]

yeh deffinately need a engine hot test doing, is it petrol/diesel, i had a show gun with the same simptoms last year but i will not be the bearer of doom by saying what that turned out to be!! every car is different but more detail of what you have done is needed!

[pvr]

If we need doom and gloom, we wait for AW8's replies

(he does not have internet at the moment so we are safe ... )

[X5Sport]

[quote=""pvr""](he does not have internet at the moment so we are safe ... )[/quote]

Still on signal fires and semaphore in that part of the country......

[CondorX5]

Well just so you don't lose the doom and gloom element in AW8s absence......when this kind of thing happened on P38 Range Rovers it inevitably indicated a slipped liner or some even more alarming issue like a crack in the block which only opens when heated, hence testing when hot. I think they did something called a sniff test as well. Usually, though, there were issues like overheating and oil/water mix seen under the oil cap....... Is there abolsutely no sign of dried water marks on the header tank and are all the hoses absolutely 100%?

[ayat]

It's a Pre-facelift diesel, the fact that it's been going on since I bought it, I'm hoping anything serious would have showed up, it's was described by the Indy as in excellent condition as I was considering getting rid. I'm hoping a more thorough check of some of the points being made will bring up the problem. I've just got back from hols so will have a chat with my local Indy again and get some coolant to top up in the mean time. I want to get to the bottom of it before I get the coolant replaced. Thanks alot will update hopefully

[thedweeb]

Can you not get a dye that you can put into your coolant that will give you an indication of where it may be leaking i.e hose?
How much is it leaking ?
Sniff test is a good one to see if you have carbons in the water.

[CondorX5]

Hmm, still a bit suspicious, given its age, of the "porous blocks" that blighted BMW at the time they made Range Rovers and early X5s , I think,..........I would have the sniff test done, just to make sure.........

[shadrack]

well if the doom is on the cards, my shogun turned out to be a cracked head! but they are only £250 new for shoguns, doubt theyre that for an x5! ever thaught who sold you it could have known the damage/problem hence selling if it has done it since you got it? just a thaught and i hope its somethong cheap

[wilkoturbo]

Mine was thermo housing small crack would leak but dry up before making a mark on the floor !

[jason@bwchiptune]

[quote=""CondorX5""]Hmm, still a bit suspicious, given its age, of the "porous blocks" that blighted BMW at the time they made Range Rovers and early X5s , I think,..........I would have the sniff test done, just to make sure.........[/quote]

In the 80-90's the m20 & m30 engines had problems with the head cracking under number 5 cylinder cam lobes
This was due to the head casting being thinner in that area
The head would crack through to the water jacket allowing water to pass into the oil
When i worked at the dealers the receptionist was told not to say it was a crack but it was a porous head so customers had to pay for it
Aluminum dose not go porous it cracks
When I started up my self I found a product which would seal these cracks for good without the need to remove and change or weld the cylinder head which we sell and it does not block the water ways up
I know a few company's that work on land rovers and range rover which buy this from us and use it to seal slight head gasket leaks

[ayat]

I know your along way away Jason but when I get some time in the new year I will try and arrange a visit, i want to remove an old super chip map and get remapped by yourself, hopefully u can give it a once over and let me know what u think.