Blew Top Radiator Hose

[morzada]

Took my daughter to soccer in the 98 M3 today. Round trip, no issues. About 30 minutes later, I went back out to the garage to pick her up and found about a half-gallon of coolant on the ground. Top hose-neck off the radiator had cracked and blown off while parked.

I only bought the car about a month ago. Car has 120K on it and still the original radiator - so this was on my list; just didn't expect it so fast. I wasn't really paying attention to the temp gauge driving back from soccer practice, but I can't imagine the car overheated. It seems to me that the pressure must build in the cooling system for the minutes after the car shuts down and the cooling system isn't operating... Yes/no?

Any reason for me to be any more paranoid about an overheat than normal?

Thanks,

EJT

[bmwdirtracer]

Hi, friend.
Hey....good news is, you've got an iron engine block!

You're likely going to be just fine. You, of course, know the drill: replace the cooling system. When the rad neck breaks, it's time for the whole refresh: Radiator, expansion tank, thermostat/housing, hoses, the plastic water pipes, water pump (you've been wanting that Stewart pump anyway).

Here's some good stuff:
https://www.fcpeuro.com/BMW-parts/M3...95&m=20&page=1

Here's more:
https://www.ecstuning.com/BMW-E36-M3...ooling_System/

[morzada]

Thanks. Just the fellow I was hoping would respond!

I notice many options for a 'refresh' don't include the heater-core hoses. I really don't want to have to take the intake manifold off; but how unwise is it to leave those hoses go?

[bmwdirtracer]

Really, I'd have to say that they're the least likely of all, to fail. That said, well, I had one fail on my old E34 M5....on the track. 3 people spun because of my coolant......

And, I'm now rebuilding a fellow instructor's '96 M3 engine....replacing all the hoses....the 3-way plastic valve that the hoses attach to, at the firewall, was rotten and broken.

If you remove the ductwork box at the base of the windshield, you may be able to access those hoses without removing the manifold, I'm not sure. But then, there's that big hose, under the manifold, and that fails frequently....

[bluptgm3]

Age of car throws a curve. But at 120k Id only change the 4 radiator primary hoses. Upper, lower, top of radiator bleed, and heater/coolant return.

[dworthy]

The only heater hoses I replaced were on my 84' M535i down in my sig, and it was only because they were 20 years old at the time and I planned on the car running for another 15 years, which it still is.

I would do the one under the manifold #6 here: http://www.realoem.com/bmw/enUS/show...diagId=11_6077

It's plastic so that should tell you something likely to fail like the thermostat housing.

[bmwdirtracer]

Damn, I can never remember when they switched the hose to the plastic pipe, under the manifold. The '96 M3 I'm working on now has a hose.....but YES, the plastic pipe HAS TO GO, they are the worst! And expect the tip of it to break off, with the o-ring, and require a pick to get it free.

[morzada]

Argh. That #6 hose is *right under* the manifold, isn't it.

I took the manifold off my 328, some years ago, but other than recalling the general stress of the whole thing, I don't remember the details anymore. I'll read up, but can you tell me, do I need to disconnect the fuel lines/rail, or can I just pull the injectors as a unit and set them aside?

[dworthy]

I would leave the injectors in place, and just unhook the fuel lines, and electrical connectors, then pull the intake off. That will keep you from having to replace the O-rings, and only the intake gaskets, which I am sure are now plastic.

[bmwdirtracer]

Yeah, German alchemy....plastic turns to rubber, rubber turns to plastic. But their metal is the best in the world.....

I agree with dworthy -- I never pull the fuel rail from the manifold, just unhook the fuel lines.

[bluptgm3]

http://www.realoem.com/bmw/enUS/show...diagId=11_6077

When Suzy's List was alive members discovered that there were error in the Diagram for these hoses - incorrect part numbers. And suggested using the 328 diagrams for determining part numbers for the hoses. Perhaps the diagram has been corrected, perhaps not.



Sent from my iPhone using Tapatalk

[dworthy]

Humm, I have found very few errors on realoem.com in the past 10 years I have been using it. At first I bounced their P/N off of the ETK to ensure it was correct.

[bmwdirtracer]

I discovered an error on Thursday. The MAF for a 330i manufactured 12/02 is NOT the part shown here for cars made after 9/02:

http://www.realoem.com/bmw/enUS/show...diagId=13_0905

The correct part for the 12/02 car is the part number ending 451, not 983.

Realoem also has several mistakes on hoses for the E34 M5, and date errors for the front wheelbearing/hubs for that car.

I've found a number of errors in realoem, over the years, but those are a few I remember.

[morzada]

I was rooting around in the car this afternoon, changing the OFH gasket and swapping out a power steering hose - I think that 'T' shaped hose is metal.