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Oil over-filling fix.


If your unit has FMTVs with serial number 100,001 or higher, listen up! Trucks equipped with C7 engines can experience oil blow-by problems due to overfilling.

Overfilling engines can blow the extra oil out of the engine breather tube. That's why Caterpillar and TACOM have decided to lower the engine oil levels in the C7 engine crankcases from 24 to 22 quarts. This should solve the problem.

During normal PMCS oil change intervals, or whenever needed, units can re-mark their current C7 dipsticks, NSN 6680-01-568-9447, PN 252-0507, to the new 22-qt range or purchase a new 22-qt dipstick, NSN 6680-01-568-9447, PN 348-6030. FMTV LTAS (long term armor strategy) trucks with serial number 705248 and above should already have this new dipstick. They were installed at the factory.


FMTV TM Changes to Come


* At normal oil change intervals, allow the oil to drain from the oil pan for at least 20 minutes.

* Remove and replace the engine oil filter and use Caterpillar oil filter, NSN 2910-01-519-3768, PN 1R1807.

* Fill the C7 engine with 22 quarts of oil.

* Start and run the engine for at least 10 minutes and then shut it off.

* Wait at least 20 minutes before checking the oil level again.


* After removing and wiping the dipstick, insert and remove it and observe the new oil "Full" level. If the oil level does not line up with the original dipstick "Full" range marks, etch a new "Full" line on the backside of the dipstick.

--Caution: Before re-marking your dipstick, ensure your original dipstick has part number 252-0507 stamped on the lower end.

--Note: Due to unknown quantities of residual oil draining back from engine components and cavities, re-marking of the dipstick may not always be necessary.


* If a new "Full" line was made, measure 1/2 inch down from that line and etch a new "Add" line.

* Using a suitable tool, make the old range markings on the front side of the dipstick unreadable.

* If the dipstick has been modified, keep future oil capacity levels between the new "Full & Add" marks made on the backside.

Helpful Hint

Never add oil to an engine that has just been shut down. Wait at least 20 minutes to allow the oil level to stabilize in the crankcase. Checking and adding oil when the engine is first shut off will likely result in overfilling the engine!

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Title Annotation:FMTV ...; Family of Medium Tactical Vehicles
Publication:PS, the Preventive Maintenance Monthly
Geographic Code:1USA
Date:Sep 1, 2010
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