The Northstar engine has a loss of coolant protection mode where 4 cylinders are shut down (the injectors are turned off) so they can cool themselves by pumping only air - then the other 4 cylinders are shut down to cool. The two groups of 4 cylinders continue to shut down alternately so as to protect the engine during a severe overheating situation and allow the driver to reach a safe place rather than be stranded on the side of the road.
It has been nick named the "camel mode" since the engine can run without water in it.
My business partner has had his Denali go into Camel Mode twice due to an errant CPU. There was not enough power to get up a small foothill and he got stranded with his family anyway. Once on Christmas eve.
Seems more of a marketing story than a valuable feature.
My business partner has had his Denali go into Camel Mode twice due to an errant CPU. There was not enough power to get up a small foothill and he got stranded with his family anyway. Once on Christmas eve.
Seems more of a marketing story than a valuable feature.
The denali is a hunk of a machine to get you up any small grade on only 4 alternating cylinders...It certainly is better to have it then to not have it, so I wouldn't conside it a marketing ploy...
Yea it has been proven in Cadillac's so I know it is not a marketing ploy. Also Cadillac tells you it is good for 50 miles but the enigne has not been show that it will stop at all. They just give the 50miles number so that people will not abuse the feature.
The Camel mode is very effective on the Northstar for several reasons:
1. It's an all aluminum engine. Without coolant it transfers heat very effectively through the entire engine and to the oil. The oil starts to become a seconary heat sink and cooling medium along with the air pumping thru the cylinders with no compustion going on.
2. The engine has a lot of power and it is in relatively lighter weight passenger cars. So it has ample power on only 4 cylinders to still move the car.
Don't forget that the 4 "dead" cylinders are still pumping air (and making no power) so the pumping losses are huge. Much of the power of the running 4 cylinders is being eaten up to pump air thru the other 4. So it isn't as though you have only a 4 cylinder engine to run the car on. More like you have an equivalent 2.5 cylinders worth of power to run the car.
3 The system was heavily developed on the Northstar originally so it is specifically tailored to that engine.
The camel mode or loss of coolant protection is very effective on a Northstar as many folks can attest to. It's way way more than just a marketing ploy. I've personally driven a couple of Northstar cars with no coolant in them - over 45 miles in "limp home mode" and then took the car out the next day just to see what would happen. The engine survived many trips like this with me and other people and was fine when filled with coolant. Max speed is about 45-50 MPH and it will slow considerably on any grade but it will get you to safety.
Several magazines have tested the system with excellent results. Motor Trend, years ago, took a car to Gilla Bend, drained the coolant and drove back to LA. The car was on a press junket at Sears Point raceway several months later and it shocked the MT scribes to see it there running fine after they had done the loss of coolant test with it - and returned it without telling anyone in the Cadillac press fleet operation.
In addition, USAC took several cars and did the independent, third party testing of the system to validate the advertising copy and such for the networks and magazines. Other GM vehicles have a version of the limp home mode also, but it is never marketed as a 50 miles at 50 MPH type of system or that it has that capability. The basic function is there but it cannot work as well as the system in the Northstar in all applications:
1. The trucks are heavy and the power in 4 cylinder mode is not enough to move the vehicle very fast and very far.
2. Some of the engines are not all aluminum and the iron blocks don't transfer heat as well and the engine develops hot spots that minimize the effectiveness of the system.
The limp home is there but it is marginally effective. It's better than nothing and any cooling system failure has the ability to just stop the car immediately so it may help and may not in any given case.
Other cars (like some of the 4 cylinder, all aluminum engines) have little or no success with the limp home mode due to the low power available when running on only 2 cylinders with less than 1 cylinder of power available due to the pumping losses.
I lost my water pump and coolant and didn't make it 1 mile. It caused my head gasket to let go, costing me $3800.. The display said "stop engine" not "idle engine"..The car is a 99 STS w/ 120k miles..
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