Engine Makes Knocking Sounds

[MOehmke]

Has anyone heard their engines make little knocking or ratteling noise at idle when the mainfold heater comes on? Is this normal? Runs fine when heater goes off.



















2004. 5 2500

running boards vent visers century cap

30 ft Sunnybrook no bombs.

 

[yycguy]

Not sure what you mean by manifold heaters "coming on", but if you are referring to the Grid heaters coming on when starting in low temperatures? a little rattling is fairly normal for the cummins or any other diesel for that matter.

hope that helps

 

[rbattelle]

The engine loads down quite a bit when the grid heaters come on. The knocking could be the infamous injector knock (good thread).



If the truck exhibits no symptoms other than a small knock when the heaters cycle, I wouldn't worry about it. Note that if it's cold enough for the heaters to be coming on then the engine will make lots more noise than when it's warm out anyway. And when the temperature gets down below 25 or so with no block heat it'll sound (and run) like a washing machine full of rocks until it gets some heat.



-Ryan