Need help with 3126 CAT

[mwskeetman]

I have a 2001 FL70 with a 3126 CAT. Bought this truck 4 months ago from the orginal company with all documneted paperwork. Truck had 147K when i purchased it. Had it checked out by local mechanic and was suggested the turbo be replaced. That was done truck has ran fine. Until the weather has changed. With warmer weather I have one hill that we climb every night that pushes the trucks heat/temp up to 225-230 range, with no Ac on. So weve changed both thermostats and drained/flushed with new coolant. Still having trouble with that one hill. Temp not as high, 215-220 but still over heating.

Also another issue is after reading the forums on here i see where you guys are averaging around 9-10 MPG. Im no where close. I run 220 miles a night same route, same load(which is light) and im getting 7.3 on the money every night.

Guys any help will be greatly appreicated.

 

[Deville]

Are you going by what the gauge in the dash reads or are you getting an actual readout from something like a scan gauge?

I can tell you my truck on a hot day loaded/unloaded, A/C on it's coldest setting running on a highway at 70mph or up a hill the temp will run 210*-215*. The fan doesn't kick on until 215*. I have seen 220* on triple digit days. The Fan brings the temp down to 190* fairly quickly.

Some guys run a separate switch for the fan in the cab so they can turn the fan off and on at there leisure.

I use a scan gauge which plugs right into the the diagnois port and it gives real time engine info. The gauge on the dash used to drive me nuts too. You aren't over heating.

As far as the MPG goes, get a valve adjustment done on that truck ASAP. I wouldn't drive it until that is done. If the guides are tight you run the risk of dropping a valve which could blow up the motor, or at the very least coast you $3000 to repair with minimal damage.

I have nearly 600,000 miles on my 3126 and the best advice I can give you is too change your engine oil and filters every 6000 to 7500 miles like clock work. Don't use the drum oil, use individual quarts. I like the Delo or Mobil. I used to use Rottella for the extra viscosity because the motor has a lot of miles on it but I found it became sooty very fast. The Delo or Mobil are better IMO.

What type of trans are you running? Change the box oil in that too.

These motors will run 750,000 miles if you are good to them.

Check this forum out. Lot's of great info about CAT, Cummins and Detroit engines.

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