540i coolant leak, failed heater control valve?

[tangalife 1]

So on my last couple of drives i've pulled up to a stop and there is a big leak of coolant coming from the passenger side of the engine. I cant pinpoint exactly but it seems to be at least below or in the general area of the heater control valve.

there is alot of water/coolant pouring out and plenty of steam. No particular smell to it. the engine isn't overheating, the temperature staying in the middle. I also dont seem to notice any leaking when the car is parked, just when the car is up to normal operating temperature.

lately there has been a huge rush of constant heat coming from the air vents by your feet when driving, this starting happening once I removed the fuses to the heater and heated water jets (trying to solve a parasitic draw problem). Now eventually I have this leak problem, probably off the back of this.

judging by these symptoms I can only assume my heater control valve has failed me, or perhaps there is leak on a hose nearby to it, but I am unable to determine exactly where. Can anyone recommened where I should look or should I just go ahead and replace the whole unit? My other thought was maybe a leaking valley pan out the left and onto the exhaust manifold creating the steam?

cheers!

Edited October 10, 2013 by tangalife

[Allanw 1071]

You need to fix this ASAP.

For one thing, a temperature gauge will only read correctly IF it's in coolant - if they level drops below the sensor, they tend to read normal-ish, if that's what the coolant temp was before the loss - I drove a Subaru a VERY long way with no coolant, and the gauge stayed just slightly under normal!. Also, an air lock can stop or reduce coolant flow, and the temperature gauge in the E39's doesn't move above normal until the engine is REALLY hot - at LEAST 115C, but probably higher, especially on the V8's, as the map-controlled themostat ones can run at 110C anyway. The OBC won't warn of high temp until minimum 120C.

I'm not familiar with the layout of the cooling system in the V*'s, so can't really help there, but I'd hate to see you cook the motor from coolant loss!

[tangalife 1]

Thanks.

Yeah well the first time it happened, I left bonnet up and went out a few hours later to top up the water. I had to put in around 3-4L of water, I was pretty worried at that point about how low it must have been.

I only drove it three other times after that. The drive home at that point was fine, I just took it easy and got home with no leaking or steaming, the next day drove it again taking it easy and no problems. The 4th drive however I drove it with a bit more intent and got home and it was leaking like the first time. Bear in mind these drives were only about 5 or so minutes long each.

FYI I have got a couple of mis fire codes but the car seems to drive pretty normal, ive had a rough idle for a while (seems to have gone away lately, once winter got over) ive been trying to diagnose a air leak for that

[Phil-540i 166]

I agree with Allan - URGENTLY needs looked at by some-one who knows what they are doing. Putting in 3-4 litres of water is not a good sign, as they're not really a air-cooled motor.

As Allan has pointed out - temp gauge will not register 'steam'.............

Where are you based??

Edited October 11, 2013 by Blue-540i

[tangalife 1]

North shore, AKL

[Phil-540i 166]

I suggest your car needs a hot date with Ray @ HellBM - Hellbm.com 0212435526 or 09 4268269 He's a member here Hellbm, user name. Whatever he'd charge to fix it, is way way cheaper than scenario of it getting cooked, or job being done incorrectly........

[HELLBM 1557]

Easy to sort. Have heater control valve/aux water pumps available.

Regards Ray

[tangalife 1]

Hi Ray, thanks any chance of getting a price (can PM if you want). Also is your shop up in silverdale? Just thinking easiest way to get there if I decide to let a pro do the work instead of myself heh.

Cheers,

(ps cheers Blue)

Edited October 11, 2013 by tangalife

[*Glenn* 854]

Hi Ray, thanks any chance of getting a price (can PM if you want). Also is your shop up in silverdale? Just thinking easiest way to get there if I decide to let a pro do the work instead of myself heh.

Cheers,

(ps cheers Blue)

You can't price something like this over the internet. The actual fault must be diagnosed / determined by the repairer to give you an estmate. The cost can also vary after stripping as these are old cars and made of degrading materials that can break when working with them.

[Phil-540i 166]

Nice that you & Ray are yarning about it. I'm a big fan of acknowledging that every-one has certain stuff that they are usually really good at (theres always exceptions to that rule though...), & I'm fairly analytical about things, so if this was my car, I'd be asking myself some questions.....

a) Whats worst case scenario / cost of me not fixing this?? (Cooked motor, effectively making vehicle un-economical to repair - wrecking value only)

B. Whats worse case scenario / cost of me trying to fix this, but getting it all wrong?? (Including doing a proper bleed of air, pressure testing system, etc etc)

c) Do I have my own previous experience / mechanical knowledge that can be called on??

d) Do I have the likely tools, parts, & work area for doing this job?

e) Etc etc to above.

Sometimes its not quite as simple as googling stuff & 'giving it a nudge', in my opinion, particulary when its your own pocket that's paying if it all goes pear-shaped.....

If you haven't got really good mechanical skills, I liken it to being a bit like finding out you've got (for example.......), a brain tumour. Would you take 4 disprin, grab a pocket knife & a mirror to do the op yourself??

Edit. Lols, Glenn since posted...........

Edited October 11, 2013 by Blue-540i

[tangalife 1]

Did some investigating in the weekend. Can't find any split hoses by feeling around, no loose connections either. AFAIK the prev owner said most of the cooling system had been replaced and some of it quite evident, so most of the things in there should be new(ish)

I have white residue directly under the heater control valve and cant seem to see any other coolant spillages at the rear of the engine or up the front. I'm pretty certain it must be coming from the heater control valve and seeing as I have the constant hot air rushing into the cabin it seems like its probably dead anyway so putting 2 and 2 togeather... I sopose it can leak from the unit itself as the hoses around seem okay my question is is it possible to leak a fair bit enough to spray onto that banks exhaust to create the steam?

If its a failed heater control unit, im confident enough to do the job myself but perhaps the more experienced people out there can warn me if there would be anything else to check or other things that could have been damaged as a result?

[kiwi535 538]

get someone who knows what they are looking at to look at it...and take it from there

[BreakMyWindow 1874]

If u remove the full cabin filter covers from the corners of the engine bay, you will have better access to the heater hoses. Sounds like one of those has a leak. There are 3 or 4 from memory behind there. Valley pan is also a common place. Pain to get to as well. Good luck.

[tangalife 1]

I removed the cabin filters when I looked, could not see or feel any splits and there doesn't seem to be any evidence there of any leaks unlike by the HCV

[tangalife 1]

PS just for future reference if anyone stumbles upon this, replaced HCV and its been all good. problem solved.

[EuroSurgeon 2]

PS just for future reference if anyone stumbles upon this, replaced HCV and its been all good. problem solved.

Usually those hcv leak out of oring between the two housings, can get from seal house, cant remember size think 21x2