Is this serious? Or did I do something stupid?

[eltax91]

Hi guys

I'm at the end of my tether with my daily motorway hack, an e61 525i.

After chasing and finally solving electrical gremlins, It's been slowly losing coolant, nothing serious. Then recently the 'loss' has gotten a bit quicker. I took it to my trusted Indy today and they attached a pump and gauge to the header tank and did various tests, and could find no leaks. Nor did the water level drop significantly. The car didn't misfire so they concluded there are no leaks and water is not going into a cylinder. The only thing they said was they could see gold speckles in the coolant, which indicated previous use of k seal or similar. They assume that's been thrown in to hide a leaky head gasket and the car moved on

I've since driven three hours ish to tonight's hotel stop with no warnings or such like in the iDrive console. I decided to pop the reservoir cap off to have a check of the level (torch in hand) and basically as the pressure released the coolant bubbled up and came streaming out of the bottle, half a litre ish, until I closed the cap.

So, question is, is the bubbling up normal or is that an indicator of trouble? Should I always check the level when cold? Am I panicking for nothing?

This car has been a money pit since January and to be honest I'm tempted to trade it and move to something reliable. So called German reliability is a myth!!

[Mound Dawg]

You should be ok, it'll do this when it's hot.

Top it up again in the morning when it's cold.

And count yourself lucky you didn't burn yourself!

[Rammy76]

eltax91 said:

Hi guys

I'm at the end of my tether with my daily motorway hack, an e61 525i.

After chasing and finally solving electrical gremlins, It's been slowly losing coolant, nothing serious. Then recently the 'loss' has gotten a bit quicker. I took it to my trusted Indy today and they attached a pump and gauge to the header tank and did various tests, and could find no leaks. Nor did the water level drop significantly. The car didn't misfire so they concluded there are no leaks and water is not going into a cylinder. The only thing they said was they could see gold speckles in the coolant, which indicated previous use of k seal or similar. They assume that's been thrown in to hide a leaky head gasket and the car moved on

I've since driven three hours ish to tonight's hotel stop with no warnings or such like in the iDrive console. I decided to pop the reservoir cap off to have a check of the level (torch in hand) and basically as the pressure released the coolant bubbled up and came streaming out of the bottle, half a litre ish, until I closed the cap.

So, question is, is the bubbling up normal or is that an indicator of trouble? Should I always check the level when cold? Am I panicking for nothing?

This car has been a money pit since January and to be honest I'm tempted to trade it and move to something reliable. So called German reliability is a myth!!

I think after a 3 hour drive there'd be a lot of pressure in the system so that'd be perfectly normal.

Not sure about why it would be losing coolant with no leaks but it must be going somewhere!

[mx5tom]

Don't know anything about that specific car, but engine coolant is usually pressurised. If you open it when hot, it can expand, shoot out and burn like hell. Not sure about bubbling, but my guess would be that what happened is normal...

On my car, the lid on the coolant container has a warning saying not to open when hot. I'd say you were lucky not to be burned.

[Dog Star]

You've undone the cap, reduced the pressure hence the boiling point of the coolant. That's normal.

[eltax91]

Cheers for putting my mind slightly at rest folks. I will top up when cold and dig out the dunce cap.

Would love to know where the 4 litres of coolant I have put in over the last 4k miles has gone though. Especially as there are no identifiable leaks!

I'm crossing my fingers the head gasket isn't goosed as that'll be the end of the car for me.

[Rammy76]

eltax91 said:

Cheers for putting my mind slightly at rest folks. I will top up when cold and dig out the dunce cap.

Would love to know where the 4 litres of coolant I have put in over the last 4k miles has gone though. Especially as there are no identifiable leaks!

I'm crossing my fingers the head gasket isn't goosed as that'll be the end of the car for me.

How many miles has it done out of interest?

[Shadows]

eltax91 said:

Cheers for putting my mind slightly at rest folks. I will top up when cold and dig out the dunce cap.

Would love to know where the 4 litres of coolant I have put in over the last 4k miles has gone though. Especially as there are no identifiable leaks!

I'm crossing my fingers the head gasket isn't goosed as that'll be the end of the car for me.

Easy to find out if headgasket's goosed by a milky residue in either the oil or coolant. First thing I look out for when buying a used car.

[METHS]

Try replacing the coolant cap.


Seems silly, but they are designed to let out pressure over 15psi, sometimes they "wear out" and leak slowly.


Leave a sheet of cardboard under the car overnight. sometimes the system will only leak while cold (happened to me).

Edited by METHS on Tuesday 23 July 23:32

[calibrax]

If it's leaking onto something hot then the leak may not be immediately apparent as the coolant will evaporate immediately...

[eltax91]

Rammy76 said:

How many miles has it done out of interest?

147k

And @shadows, no milky residue here! But where the hell is it going? The Indy had the pressure up when both cooling down and then when cold. Neither time could they find a leak, nor did it lose hardly any coolant.

It's weird for sure.

[Shadows]

eltax91 said:

147k

And @shadows, no milky residue here! But where the hell is it going? The Indy had the pressure up when both cooling down and then when cold. Neither time could they find a leak, nor did it lose hardly any coolant.

It's weird for sure.

Not sure mate, but I'm not a day to day mechanic. As a hobby I rebuild oldish cars and stick turbochargers etc. on them for a laugh . But mainly doing Alfa's come across my fair share of headgasket / coolant issues. K-Seal isn't a permanent repair, I know some who have got away with it.. But the issue could of surfaced again and K-Seal blocked it again at a hugely large guess, remembering the old Rover K-series, it stayed in the tank and blocked holes as they arose. Murky coolant is the biggest giveaway of K-Seal..

Would explain why you lost coolant then it passed a pressure test.

Edited by Shadows on Tuesday 23 July 23:46

[eltax91]

METHS said:

Try replacing the coolant cap.


Seems silly, but they are designed to let out pressure over 15psi, sometimes they "wear out" and leak slowly.


Leave a sheet of cardboard under the car overnight. sometimes the system will only leak while cold (happened to me).

Edited by METHS on Tuesday 23 July 23:32

There isn't any evidence of a leak on the bottle or anything, but a cap has to be worth a bash, so will do.

Ta

[littleredrooster]

Shadows said:

Easy to find out if headgasket's goosed by a milky residue in either the oil or coolant. First thing I look out for when buying a used car.

Only true if the gasket fails between oilway and waterway. Oil and water mixing will form the telltale 'mayonnaise' somewhere.

If it fails between cylinder and oilway, oil will go black very quickly and may blow out of breather or dipstick.

If it fails between cylinder and waterway, it will pressurise cooling system and blow it past the pressure cap, until it cools down then it will suck it back into the cylinder and start in a cloud of steam next time around.

I've had all these combinations in my time.

[Shadows]

littleredrooster said:

Only true if the gasket fails between oilway and waterway. Oil and water mixing will form the telltale 'mayonnaise' somewhere.

If it fails between cylinder and oilway, oil will go black very quickly and may blow out of breather or dipstick.

If it fails between cylinder and waterway, it will pressurise cooling system and blow it past the pressure cap, until it cools down then it will suck it back into the cylinder and start in a cloud of steam next time around.

I've had all these combinations in my time.

Learn something new all the time ..

[gavgavgav]

eltax91 said:

147k

And @shadows, no milky residue here! But where the hell is it going? The Indy had the pressure up when both cooling down and then when cold. Neither time could they find a leak, nor did it lose hardly any coolant.

It's weird for sure.

For the pressure test, is it connected using a testing cap? i.e. not testing the cap you have?

[Burbleboy]

My track E39 535i lost water when i had it road legal. Excess pressure in header tank and lost water. Head gasket tests revealed no issue.

Turned out the car had not been bled properly after a recent coolant change! Honest, took ages for that to bleed through. No problems after that. Hope this helps....

[Coatesy351]

Is the heater leaking from somewhere?

[Mound Dawg]

gavgavgav said:

For the pressure test, is it connected using a testing cap? i.e. not testing the cap you have?

That's a very good point. If the Indy is using a cap with a pressure feed in it then they're not testing YOUR cap which could be the problem...

[eltax91]

Mound Dawg said:

That's a very good point. If the Indy is using a cap with a pressure feed in it then they're not testing YOUR cap which could be the problem...

You are both correct, he was using a specially adapted cap with a bicycle pump and pressure guage attached. I will try another cap just in case, however to be honest the evidence of k seal has me worrying its far more sinister

Lets imagine the gasket is damaged between waterway and cylinder, and it only lets water into the cylinder as it cools down, just how obvious would steam be on the next startup? I mean, does just a few drops of water cause it to billow out or would it easily go unnoticed? Would I expect a misfire on startup for example?

Also, lets imagine it is, what's the bill for a strip down, head skim and gasket set on a 6 cyl bmw? Is it time for more k seal and trade it in??