[bumpin96monte]

I was looking through a textbook I borrowed from a buddy (Engineering Fundamentals of the Internal Combustion Engine-2nd edition)- it had a statement in there under the cooling section that one of the byproducts of the DOD on GM's 5.3 was the fact that even if the engine coolant was run dry, the engine could still operate (under limited, and lower speed conditions) without overheating by running on 4 cylinder mode. The idea was that, the cold air being sucked in and blown out by the 4 deactivated cylinders was sufficient to get rid of the excess heat produced under low load conditions.

Just wondered if anyone had heard about this before. Not that I'd ever try driving an engine with absolutely 0 coolant in it, just thought it was interesting that it could practically run in an air cooled mode.

[Manitcor]

Sounds feasible in theroy, I wonder if anyone has tested that fact though.....

[lav74]

Manitcor, on Mar 9 2007, 09:50 PM, said:

Sounds feasible in theroy, I wonder if anyone has tested that fact though.....

I don't think anyone wants to put themselves in that situation to test it. LOL

If I had the LS4, I know I wouldn't. :

[mstrjon32]

I didn't read the part about the 5.3, but in my 2006 owners manual, it says that should my 3900 overheat, it can still be driven to "safety" without damaging the engine. The manual explains that the display will read "Restricted Performance", and the engine will switch between operating on opposing cylinder banks at some interval, allowing for the other to cool down. Supposedly it will just cut fuel and spark to the other side, since obviously it can't "deactivate" those cylinders.

It also talks about how if the car overheats, you should continue to follow the instructions in the DIC in order to prevent engine damage, and in some situations it will read "Idle Engine", and others it will indicate "Stop Engine", depending on a variety of factors.

Certainly much fancier than my 3100 which would just overheat, continue to run full-steam until you noticed the damn thing was overheating, and then warp the head.

[gordornr]

even better protection during overheating would be to turn the spark off for half the cyliners, leaving the fuel to help cool the engine. of course that would waste tons of gas and probably ruin your cat. oh well

[Ravant]

I believe the 3900 cuts off the injectors though as well, at that point.

[adhood]

I might be wrong.
But I believe that the Cadillac Northstar engine(s) will shut down one cylinder bank to provide cooling during a lost of coolant.


Edit: I was correct
One notable feature, advertised at the time, was the fail-safe cooling mode which allowed the engine to continue running for a limited time without any coolant at all. It alternated banks of cylinders to maintain cool temperatures, allowing a Northstar-equipped car to be driven with no coolant for about 100 mi (161 km) with no damage.

From wikipedia: http://en.wikipedia....remium_V_engine

This post has been edited by adhood: 04 April 2007 - 03:56 PM

[mstrjon32]

adhood, on Apr 4 2007, 03:51 PM, said:

I might be wrong.
But I believe that the Cadillac Northstar engine(s) will shut down one cylinder bank to provide cooling during a lost of coolant.


Edit: I was correct
One notable feature, advertised at the time, was the fail-safe cooling mode which allowed the engine to continue running for a limited time without any coolant at all. It alternated banks of cylinders to maintain cool temperatures, allowing a Northstar-equipped car to be driven with no coolant for about 100 mi (161 km) with no damage.

From wikipedia: http://en.wikipedia....remium_V_engine

Yeah, that's basically the system in the new Monte.

[Malibu603]

I'm not sure if you can run it with no coolant, but I'm pretty sure that when the engine switches to V4 mode, the lifter collapse, and therefore no air goes in or out of the cylinders that are shut off. It still might be able to run because of the increased thermal mass (being a V8 running like a 4 cyl), but I don't think it's because of cool air being sucked in to the closed cylinders.