Foam from E39 radiator

[5seriesrocks]

Not sure if anyone has advice on on this problem

I have a 2002 525i that has a problem with overheating some times and white foam gushing from underneath the water bottle cAp while I'm driving

All started few months ago when she started overheating, my mechanic then the found the top gasket to be blown which he replaced. Not long after that the water bottle just suddenly decided to explode after overheating again. I then had it replaced but that wasn't the end of it.

There was still pressure build up in the water bottle. Mechanic then said there might be crack in cylinder head and I should try a metal bonding fluid in the cooling system. I tried that but problem persisted but now with foam gushing from the water bottle while I drive.

Mechanic now says that it definitely seem like crack in the head, to be removed and sent for pressure tests.

The thing is that I should probably get a 2nd opinion before I give out more money to ensure that the problem will be fixed once and for all. She's been parked now for about 6 months and it's sad for me to see her just gathering dust.

Anyone with advice out there?

 

[Gordvisr]

it might be something simple as the water bottle cap, try it first, i have seen this happen previously. insdie the cap is a pressure relief valve and should only relief pressure on the inside of the bottle when neccesary and to keep the water inside the bottle. A cap should not be too expensive.

You said the bottle burst first, this could be that the pressure relief valve stayed close, and currently water is escaping from the cap that tells me it has failed completely now.

Hope this is the problm and not the head.

This problem on the cap usually starts after an overheating problem and to be on the safe side , replace the thermostat aswell

 

[5seriesrocks]

I think I'll try this first. Do you have any idea how much a thermostat might cost?

Also, couldn't it be that something else cause a build up of pressure causing the bottle to burst?

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Is the foam also a common thing?

 

[RAArmstrong]

Take the car to Gizmo, he'll sort her out

 

[Gizmo]

:withStu:
Your mechanic is an idiot, the head is cracked, he should have picked it up when he replaced the head gasket. He is taking you for a ride.:sorry:

 

[zaleonardz]

In the words of Mr Denis Leary, "Life is going to suck when you grow up"

Simple answer, your mechanic failed you first time around.

Its pretty clear that you are mixing compression gasses into the cooling system,

THe first instance of overheating, it is possible that the cylinder head could have been cracked, however your mechanic should have picked that up on the first disassemble.

A loose cylinder head is easy to have tested, and if you did not want it professionaly tested, he could have tested it himself.

More then likely here, if it was fine for a couple of days, is that the head was not torqued correctly. and within a few 100 km, it actually vibrated loose, or it has actually warped from improper tightening methods.

I concur, take it to Gizmo, or somebody that knows what they are doing...

 

[5seriesrocks]

You its so difficult to get someone reliable bcoz there's so many that claim they are beemer specialists, I had one that worked on my e46 then he ripped me off then I thought I found a reliable one now

gizmo where are you based I'm in cpt or can you recommend someone reliable and affordable down here

So this is definitely cracked head, bcoz this mechanic seemed to be looking at it on a trial and error basis

 

[Gizmo]

Garage 808 apparently do good work. I'm 1600km away from you unfortunately.

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They in Belleville

 

[5seriesrocks]

Seems like there's quite a lot of good reviews and threads on them. Thanks a lot