BMW Forums : BimmerForums banner
1 - 20 of 21 Posts

·
Registered
Joined
·
46 Posts
Discussion Starter · #1 ·
Hi all,
This is really a follow on from a previous thread from a couple of months ago.
I am still having coolant loss issues... I had a Sniff test carried back in October and that proved negative, pressure tested, no leaks found but still coolant loss continues... took it to a stealer, pressure tested nff. Still coolant loss. In the end took it to a place recommended on here and they did the tests again, nff and the dropped the coolant and replaced.

Replaced Rad Cap....

Still I'm losing coolant!!! I reckon I've lost in the region of 1/2 a litre in 150 miles since the change. I keep topping it up but keep thinking the worst!!! dreaded HG.

Now it has never over heated, it has never misssed a beat, no misfire when started hot or cold, went to devon a back over Xmas with no issues and when driving down and around devon the coolant seemed to stay at the same level; I thought Ah, the rad cap fixed it and it just had a bit of air in the system... then on the journey home, you guessed it, popped the bonnet and checked the next day, coolant down by approx 2cm...

This is doing my head in now. It's going back into the garage on Monday but the issue is that my sister is supposed to be borrowing the car when she comes back from Oz in a couple of weeks with two very young children so I can't lend it to her if there is any real chance of there being an issue.

Does anyone have any thoughts on this... Thanks in advance for your help guys!!!!

Paul
 

·
Banned
Joined
·
478 Posts
Its definately not coming from the heater matrix??

On my old 7 series, i had a similar problem actually, it was a hose, but, only when i revved the engine to about 4,000 rpm would it squirt coolant out. And it was a hose that went into the bulkhead that was split, if i recall correctly. Id check for anything similar.

Sniff tests are usually accurate, and pressure test are conclusive, so it must be leaking elsewhere. If you are losing that much, you will almost certainly will notice engine performance drop in the form of difficult starting and poor cold running. Also, if it was the HG there would almost certainly be mayo around the filler cap if you are losing coolant like that. I would'nt immediately jump to the HG just yet, there is no real evidence suggesting it.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #3 ·
Thank Mighty!!! My thoughts were centering around the Heating system but I would have thought that this would have shown up on the pressure test...?
 

·
Banned
Joined
·
344 Posts
Thank Mighty!!! My thoughts were centering around the Heating system but I would have thought that this would have shown up on the pressure test...?

There is a coolant flange at the back of the engine on the cylinder head between the bulk head- it is not easy to see. Over the years we have replaced several of these on the 6 and 4 cylinders as they do tend to leak.

Can u not see any coolant stains anywhere else? around water pump, thermostat, rad? What about the expansion tank?
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #5 ·
Nope, no white deposits or any of another colour anywhere to be seen... I'll get them to check the coolant flange though... Thanks for the advice!
 

·
Banned
Joined
·
478 Posts
A few things you can check also, Do you burn lots of white smoke? (not to be mistaken for normal steam)

Also, pull the dip stick out and take a look at the oil, wipe it onto some white kitchen roll and try to see the colour, if it is 'milky' then that is coolant in the oil.

I can't remember off the top of my head, but im sure there are gearbox cooling pipes that go from the radiator to the autobox, it may be worth checking this pipe, and the seal to the autobox, this may have been overlooked on the pressure test.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #7 ·
No white smoke and I'm pararnoid so check the oil and it looks oil coloured... no sign of mixing at all.... I'll get them to check the pipes and seals you mentioned...Thanks again!
 

·
Banned
Joined
·
478 Posts
It terms of your wallet, thats good news, so it has to be leaking somewhere else. Good luck, let us know how you get on :thumbsup
 

·
Banned
Joined
·
478 Posts

·
Registered
Joined
·
46 Posts
Discussion Starter · #12 ·
Right... The garage left it on Pressure test all day with no loss what-so-ever... They then left it overnight and it lost pressure and there was a puddle of coolant under the car so looks like somethings contracting at a different rate to the rest of the stuff... Any ideas anyone... Looks like it's from the back of the engine... Any Ideas gratefully received!!!!
 

·
Banned
Joined
·
478 Posts
Mate... im absolutely puzzled... I would have said a core plug, especially with all of this cold weather, but a pressure test surely would have picked this up, Im going to make some enquiries for you, but it is very confusing. There is a chance that the heat is sealing the leak somewhere, has it been pressure tested when hot?
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #14 ·
Yep... Tested hot and cold and only showed up when it was left on pressure overnight. Tbh I think the garage are as puzzled as anyone, not to say they're not working hard to resolve it. If you could make some enquiries that would be great. I have to say I do feel slightly vindicated as the missus and most of my mates said I was imagining it... Even the garage thought I was worrying about nothing... Just glad there's an external leak! Cheers for your help again... I'll keep you posted on any findings!
 

·
Banned
Joined
·
478 Posts
I have a theory.... I think im right in saying you car has water valves and a may have an additional pump for the heating system,

http://www.realoem.com/bmw/showparts.do?model=DD62&mospid=47544&btnr=64_0691&hg=64&fg=18

http://www.realoem.com/bmw/showparts.do?model=DD62&mospid=47544&btnr=64_0676&hg=64&fg=18

Unless the heating was switched on in the cabin the valves would probably be closed and probably render the pressure test around the matrix and associated hoses useless. The pressure test would have ruled out a lot of common leaks as they have not shown up during the pressure test. I am getting more and more confident that your problem is with the heater system. Trouble is the matrix are a pain in the arse to get at, so you really need to be sure that it is this that is leaking, with it being behind the bulkhead. Try running your engine from cold and put the heaters on in the cabin at full heat and fully open at fast speed. Let the car fully heat up and get an eye out for visible leaks, heater hoses, look under the car for drips. After is fully reached temp, and the fans are blowing hot leave it running a further 10 mins, keeping an eye out in the process. If you see nothing, go for a couple mile drive, and repeat the above. If still no joy... turn the engine off, leave the heater controls as they are, and let it cool down, the system will be pressurised so any leaks may present themselves, due to the pressure slowly reducing. so keep looking under the car. Let us know how this goes....:thumbsup
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #16 ·
Cheers mate... Good info there... I'm going to pass this to Garage doing the work if you don't mind... I don't like the sound of the heater matrix being buggered though as I had one go on my 300zx and that cost a fortune to replace.... Anyhow I'll keep you updated! And I believe that the unit that you are referring to has a button called REST in the cabin for using the Latent heat gathered from the engine to warm the cabin when the engine is turned off... i.e. when sat at a level crossing (i think that is what it says in the manual) anyhow cheers for chasing mate!
 

·
Banned
Joined
·
478 Posts
Maybe my info, may get the experts 'thinking' im by no means an expert, but you'd be suprised at how many times ive spoken to the experts, and 'rang a bell' with various researching that i conducted. I rebuilt my reliant scimitar, mostly myself, but that is simple engineering, bmws are somewhat compicated. If you can work on a bmw, then you are a electrician, mechanic, and a wizard.

But if you losing coolant at the rate you are doing, then you most definately have a leak, so it needs to be found, just in case you are miles away from town and it dumps the fluid altogether!
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #18 ·
Yep... Even worse is that my sister will be borrowing the car when she comes over from Australia at the end of the month so I need to know it's going to be OK as she has a 4 month year old baby and 4 year old son to deal with aswell... again cheers for your help matey!
 

·
Banned
Joined
·
478 Posts
No problem mate, keep us posted:thumbsup
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #20 ·
I will Update this to fixed when I have confirmation that pressure holds overnight... But it turns out it was the Stat housing leaking according to the garage... new one ordered and installed and see if it holds pressure over night... So there you go... seems a bit odd to me but hey ho... I'd like to change the tags on this post as this has been a pig to find and been ongoing for months... so any ideas as to what to add as tags to make it easier for others to find?
 
1 - 20 of 21 Posts
Top