Overheated 1990 535I - Is it OK?

[vping]

I posted some part of this on another thread but to recap my daughter is driving the other day and blew a heater hose. It's the really complex hose at the firewall and has many twists and bends. the temp was in the red when she shut it off. Towed it to the repair place and they fixed it for her. The cost to replace all the others was really pricey so we opted not to do it.
We were texting back and forth about it and I told her to call me when she picked it up cause I really only wanted her to drive it locally. Well she did call me but she was a few hundred miles from her school and she called to say she blew another hose. It was the short 2" diam curved hose to the thermostat housing. The split was right by the clamp which was good. She was able to wiggle the hose on, moved the clamp over the seam tightened the clamp, filled it with fluid and tried to burp it. The bleeder would not open so I told her to leave it rather than break it. She had a 3 hour drive back to school and I told her to take it easy and keep the heat on full blast. After two hours she stopped for gas and there was steam coming from under the hood but the gauge was not in the red. The steam was coming from the same blown seam. I told her to let it cool add fluid and carry on but keep an eye on the gauge. She made it back to school.
I came up to take a look. I was able to remove about a quarter inch of hose and get it set in place. Filled it with fluid and took it for a 20 minute drive.

Temp gauge at 12 o'clock
System was pressurized and no signs of hissing ( is this normal)
Car had same power it had before.
No water noticed in oil
No oil noticed in water

When I got the car a few years ago I noticed white steam from exhaust but it dissipates after its warm. I notice it now after her over heating problems.

I plan on now replacing all the hoses (hindsight is 2020 as I should have done it years ago) along with the thermostat.

So is it just bad luck that the car blew two hoses in a week?

Is it the thermostat causing it? The Water pump?

Car seems fine other than stinking like antifreeze from it pissing out so many times.

If you can answer all the questions before I sink all this money into new hoses and such I'd appreciate it.

Cheers
Vince

[Paul in NZ]

sounds like it is ok...."steam" out the exhaust is normal in cooler temps.I would say that the price of a few hoses is worth it to see if things are ok,what else are you gonna do?

[WCora]

Nice ride, man.
I have the same one, but mine is white. My wife is about it.

[genphreak]

Its easy to rationalise and say its old hoses but something may be causing a higher pressure in the system so now they are starting to let go (thermostat?). If they are old, of course they may be root cause, but if you haven't changed the various cooling system wear items, now sounds like the time to do it. Also make sure you are using an approved or at least (well proven in BMW, Volvo) coolant in the right ratio for your weather.

Oh yea, sometimes the bleeder won't bleed. You just have to remove it and clean corrosion from the hold with a pin. If your girl is doing doing big drives, it'd be worthwhile.

All large sixes can leak coolant into the exhaust when warming up, the gaskets leak as the block and head expand at different rates. My M30 did it for years and years before blowing a small leak to the outside, not the cylinder side. If you smell coolant, check if it isn't in-cabin o rings on the heater core- its dead easy to pull all the dash bits to get in and fix it up with $4 worth pf parts.

[Paul in NZ]

Its easy to rationalise and say its old hoses but something may be causing a higher pressure in the system so now they are starting to let go (thermostat?). If they are old, of course they may be root cause, but if you haven't changed the various cooling system wear items, now sounds like the time to do it. Also make sure you are using an approved or at least (well proven in BMW, Volvo) coolant in the right ratio for your weather. Sometimes the bleeder won't bleed. You just have to remove it and clean corrosion from the hold with a pin. If she's doing big drives, I'd say it'd be worthwhile.

The large sixes will leak coolant into the exhaust when warming up, the gaskets leak as the block and head expand at different rates. My M30 did it for years and years before blowing a small leak to the outside, not the cylinder side.

mine did it for months and months before i got it fixed ,never actually blew properly

[Ross]

If you are seeing steam again you should investiagte the (likely)possibility of a failed head gasket. It could be the result of the overheat or the cause of the hoses popping, I suspect the latter. Even though it's not currently overheating it sounds like the cooling system is being over pressurized.
Inspect your spark plugs, coolant in the combustion chamber has a steam cleaning effect, removing carbon. A super clean plug among regular appearing ones is almost a sure sign of a failed head gasket or a cracked casting. There are also kits available to check for combustion gases in your coolant. I'd check this before investing a bunch in new hoses. The decision to fix or not can then be made without throwing good money after bad.
M30 engines will take a moderate overheating better than later engines, a gasket job might be all it takes to get it back in good health.