What kills the bearings with a coolant leak?

[Gary Allan]

Okay ..okay ..I've blown off all the DeathCool threads since I don't own one of the GM engines that had the lame intake gaskets. Now the number of posts involving lame intake gaskets masks what I'm trying to figure out. My ignorance ..my bad

Now let me preface this by saying that, sure, water in your oil isn't a good thing. We don't like it anymore in marine environments then we do in any other situation ..let alone having it induced directly into the sump via faulty intake/head gaskets and what not.

Is it some component of the coolant (abrasives in any form) ..or just the corrosive nature of having the TBN depleted so rapidly that "takes out your bearings".

I couldn't find the Cliff Notes on this.

Why do I ask this? Don't ask

 

[Virtuoso]

It's the glycol in the coolant that kills the bearings. It dosen't like to lubricate at all.

 

[brianl703]

I read in the coolant forum that propylene glycol, as used in Sierra coolant, doesn't kill the bearings as much as ethylene glycol.

 

[Bryanccfshr]

What does alchohol do to lubricity??

 

[Gary Allan]

Hmm alcohol would be a low boiler ..not a good coolant. It would probably be liberated well from the oil ..taking some water with it. ..or so I would imagine.

So our prop's don't kill them as soon. Just deal with the moisture ...keep the TBN up ..and pray that you can wait to afford the long block.

 

[rpn453]

If I remember correctly, the tribologist that taught a few of my engineering classes said that coolant has a greater affinity for metal than oil and almost no shear strength. So I guess it would be more likely to cling to the bearings as a film while the oil gets pumped through, providing very poor lubrication at the same time.

I believe the density is higher than motor oils so it would also stay on the bottom of the sump and be more readily drawn into the oil pump.

 

[Kestas]

Water (or coolant) and oil form an emulsion that has poor lubricating qualities. It doesn't take much coolant to make this emulsion.

In the bearing industry we allow no more than 1-2% water in grease before it needs to be regreased, depending on the grease used, because of this emulsifying effect.

 

[Pablo]

I thought it was the water mainly and microexplosions at contact areas....these cause pitting and then nasty streaking, and bearing death.

 

[Shannow]

Pablo,
that was my thoughts as well, cavitation in the release area after the oil has gone under the wedge.

 

[RB Shannon]

Here's a good article from Practicing Oil Analysis magazine on how glycol reacts with HDMO'swhich should be similar. How Glycol Causes Corrosion and Oil Ball Damage - In Diesel Engines

 

[Gary Allan]

I had envisioned a "flashing off" of evaporative elements on the bearings as being a slow death. The droplet and the "oil ball" thing (the article = thank you!) seems really bad. Micro bombardment. It appears, from the article, that heating actually increases the incidence of ball formation.

 

[BearZDefect]

Reading the article RB linked for us, can we guess that using a low or no Ca oil in these GM engines would reduce the risk of bearing failure?

I have seen varying levels of Ca in oil analyses but do any formulations omit it completely and use other additives instead, like Mg based?

 

[Gary Allan]

I wondered that myself. I had considered going to HDEO to help combat this situation ..but given the ultra high detergency (CA being one of the principle components) it may just make matters worse