Alu M52 Overheating --- Update: Sill having issues

[Chilezen]

This looks like the reaction when the incorrect water is used. I bought my 86 325 and the head / thermostat housing was chock full of that stuff. It is aluminum corrosion.

How well grounded is the engine?

That's the answer I got elsewhere. This could be from when I had to add water due to a leaking head gasket. I had to drive the car (no other option) and distilled water wasn't always available... so tap water was used. It wasn't in there long, I did empty it a number of times to diagnose that particular issue, but I guess the damage had already set in.

So now I'm googling the best way to remove aluminum oxide deposits.. which seems to parallel calcium buildup. In this situation, people are saying to use vinegar and baking soda. I'm wondering if that can be safe to using in an engine. More googling...

Why do you ask about the grounding of the engine? I would say it's fine.. I don't know how much better it could be.

[jbontke]

Why do you ask about the grounding of the engine? I would say it's fine.. I don't know how much better it could be.

The thermostat housing in my 325e was completely blocked by the corrosion. Interestingly it had a ground point there as well. I mention the grounding because of the electrolysis effect of the tap water and a poor engine grounding. Make sure the engine has the same grounds as the e36 offered and they are clean to keep from making the corrosion problem worse. In the case of the eta engine, I am not certain that the ground on by the thermostat housing was making the issue worse, it was just interesting.

https://www.vehicleservicepros.com/collision-repair/on-the-shop-floor/article/21167263/metal-shop-electrolysis-and-grounding-101

[Northern]

With how many things you've removed from the engine, it's wild that that chunky stuff only showed up now.

Not sure if I'd jump straight to replacing that rad, back flush it with water, or try to dissolve that crap with some gasoline or what.

[Chilezen]

With how many things you've removed from the engine, it's wild that that chunky stuff only showed up now.

Not sure if I'd jump straight to replacing that rad, back flush it with water, or try to dissolve that crap with some gasoline or what.

As a matter of fact, this has been appearing for a long time, as first pointed out last March.

One extra important bit of information: Every time I drain the coolant, there's always debris. This is metal flakes mostly, and some tan bits of, something. Yes, there appears to be a thread shaving on the left. And a bit of black gasket stuff (?) next to it. This is exclusively drained from the radiator, and I cleaned the pan prior to filling.

The problem has probably not gotten worse because of how frequently I drain the gawddaymn coolant. I'm only focusing on it now because there aren't bigger problems to address anymore (a small win! lol)


So yeah, despite multiple flushes, the early batch of tap water may still be causing this issue. Super flushing the rad alone might be enough. With gasoline, you say? I'll have to look that up. I've used it to clean parts before, but I never expected it to take care of calcium buildup.


I checked the rest of this thread and saw another mention of debris:

I have replaced the factory water pump with a Stewart pump. I do like the design of the Stewart, the way it directs the water up. Pretty smart.

Upon inspecting the factory pump, I found..... nothing of interest. It looked fine. No rubbing or scars on the impellers. Spun freely, quietly.



It had a little bit of "grit" stuck in with the lube around the O-ring, which I thought was odd, but I've already been seeing debris come out in the coolant, so it's no surprise to see it there.