[Overheating] How much is too much?

[Breeze1]

Hello all,

So my car overheated today, due to a thermostat failure. Luckily (well I hope so...) I caught it before it went into the red (the needle reached about 3/4). I had my laptop with me so I hooked up INPA immediately after pulling over and shutting down the engine and found that the coolant had reached 120°. How bad is it for a M52TUB28?

Thanks!

[ross1]

I doubt a brief hit at that temp would hurt it.
Fix the cause and monitor closely until convinced it's okay.

[Breeze1]

Thanks for your reply. The thermostat has been changed as well as the pump, because it had became noisy. After letting the car idle until it reached operating temp (90° according to my settings), I monitored it with INPA.
The coolant temp showed 90 and the outlet temp was going back and forth from 75 to 90, following the electric fan's operation.
Does that sound ok?

I'll keep monitoring it for a while of course.

[Breeze1]

About the coolant, I know there is a specific "blue" one recommended by Bmw, which is why I asked my indy not to put any coolant in the car (just distilled water) until I put some HEPU (german stuff, good quality blue coolant) in it, but unfortunately he seems to have forgotten or disregarded what I said. He put some (blue) "Bardhal 10% mix" in it. Is it ok or do you guys recommend flushing it and putting the HEPU in? As far as freezing is concerned there will be no issue because temps never drop below 5°C where I live (even 5° happens rarely).

[ross1]

I don't belong to the only OE fluids/parts school and certainly not the German is always better school.
Changing the coolant at reasonable intervals is more important. Green or blue are fine for me, just don't mix them.
My car has green, Mrs. Ross' car has blue, both cooling systems are doing just fine.

[Breeze1]

That's good to know, thanks!

[Breeze1]

Please bare with me while I'm being paranoid (it tends to have that effect on me when a car overheats, even "not all the way to the red"). How does that hose look to you? Especially the part circled that looks a bit swollen. It could have been there before but now that it has overheated and that I remember noticing the whole thing was kind of swollen when the temp was 120c, I'm wondering if it's still good or if I should just replace it? In other words, does a new/in good shape hose present that kind of swelling?

I don't mind replacing it if need be, I just don't want to unecessarily throw money down the drain...

IMG_20200131_205920.jpg

[ross1]

I think you are seeing the barb on the radiator neck. This is what keeps the clamped hose from slipping off. Unless the rubber feels gummy, is swollen at the ends or has palpable soft spots I'd not worry. On the other hand it is cheap and easy to replace so if unsure of it's age and changing coolant anyway I'd perhaps swap it and others.

[Breeze1]

Thanks. Actually the pic is taken from tje thermostat side. There does seem to be some plastic underneath the part that looks a bit swollen and none of the symptoms you describe are showing. Since I've noticed that the new coolant seems to be dislodging some white "flakes" from the cooling system, I'll give it some time to do some cleaning and then I'll flush the coolant and replace the hose.