2 questions. If my Cummins is a 99 with a 24 valve engine, does that mean it is a 99 and not a 98.5? Also, I had a heavy duty bumper and grill guard installed this spring. The truck will run to 200 or so on a grade in high ambient heat. I really don't know what is standard. There is a lip on the grill guard that sets up about 3.5 inches and covers about 10-15% of the radiator. Should I have that lip cut out? It doesn't seem to run any hotter with or without the grill guard, but I confess to not checking very closely when I first got it. What do you people think?

 

The 24 valve engine replaced the 12 valve midway through the 1998 model year. This prompted owners to create the .5 suffix the denote the later 24 valve trucks from the earlier production.

Ther is also a .5 designation applied to the 2001 year. This one denotes the addition of 4 wheel disk brakes.

 

Thanks WestTN, cleared that up.

 

About your running temp. Check your radiator. There is an overflow bottle on the front of the engine (drivers side of engine) for the blow-by tube. That bottle with fill up with crud. On inclines or when its too full the stuff inside it will spill out and get thrown all over by the fan. When it does that the oily mess gets into the radiator fins and collects anything being pulled throw it and clogs it up over time. Mine was running 200* or so going up hill empty or idling in hot weather, cleaned the radiator out and now I it stays about 170-180*.

Before

After



Use simple green and a power washer to clean it. Relocate the overflow bottle when you are done so it doesn't gunk up again.

 

Thanks for the help. Those are great pics before and after. I'll give it a try before I get going with my fall camping and submit a new post about the results. Did you need a fin comb when you were done powerwashing?

 

No, I didn't need a fin comb. I kept the power washer about 18 inches away and it did fine. Just let the crud soak in the Simple green for a little bit before power washing (or you can use a hose with your thumb over the end, takes a little longer) The whole process is easy,only part that took the longest besides the soak/washing was draining the coolant before removing the radiator. Glad the pics helped!