How to: Installing a 3.9L Cummins dual valve cover and breather assembly on a 12-valve 5.9L Photo Gallery
Bruce W. Smith –
Jun 12, 2017
Photo 1/13 | Just Venting Cummins Lead
Photo 2/13 | 003 Just Venting Cummins Parts | Mobile Diesel Service uses a pair of Case IH/New Holland dual valve covers (PN 2830784) with matching breathers (PN 504069558) from the 3.9L Cummins 4BT engine to replace four of the six stock valve covers on the 12-valve 5.9L powerplant in a workhorse ’96 Dodge Ram 2500.
Photo 3/13 | 004 Just Venting Cummins Bolt Grommet | The new valve cover actually uses the 5.9L’s special shoulder bolts, but Ruben Villalobos removes the O-rings and replaces them with grommets that are commonly used on 6.0L Ford Power Stroke engines. The grommets just happen to fit in the new valve cover’s recessed area, as if they’re made specifically for that application.
Photo 4/13 | 005 Just Venting Cummins Removing Valve Cover | The first step of the procedure is getting rid of the 5.9L’s inner valve covers. Don’t discard them, as they can be cleaned up and used around the shop to hold small parts and such.
Photo 5/13 | 006 Just Venting Cummins Vcovers | The 3.9L Cummins’ dual valve covers are designed to route the oil from the breather that bolts on top back down into the engine. This also reduces oil consumption.
Photo 6/13 | 007 Just Venting Cummins Install New Cover | Ruben swaps the four stock 12-valve covers for a pair of Case IH/New Holland 3.9L Cummins 4BT dual valve covers. The aluminum covers come unpainted, so Ruben hit them with a coat of black semigloss to blend in with the other parts. (We could have used just one valve-cover assembly, but a pair balances out the overall appearance).
Photo 7/13 | 008 Just Venting Cummins Imapct Driver | An impact driver makes quick work of tightening each of the shoulder bolts until they come in contact with the valve cover, at which time the grommets are sealed in the recess.
Photo 8/13 | 009 Just Venting Cummins Oring Breather | It’s important to make sure the breather includes the sealing O-ring. Notice the baffles on the inside and underside of the breather that help catch oil blow-by and force the droplets back down into the valve cover.
Photo 9/13 | 010 Just Venting Cummins Install Breather | The new breathers are installed so the drain-hose outlets point toward the firewall. That way, they can be joined together with a “T” fitting and the hose can be run over the rear of the block and down toward the starter.
Photo 10/13 | 011 Just Venting Cummins Vent Hose | There’s no pressure on the breather’s vent hose, so ¾-inch heater hose is used to run from each breather’s outlet. We doubt the hose will see oil dripping out of it, thanks to the breather’s design. That’s a good thing!
Photo 11/13 | 012 Just Venting Cummins Tee Fitting | All that’s needed to tie the two breathers’ tubes together is a ¾-inch plastic T-fitting. The hoses are later secured with plastic zip ties.
Photo 12/13 | 013 Just Venting Cummins Finished Install | The two agricultural-style Cummins dual valve covers look right at home under the hood of the ’96 Dodge Ram 2500 after Ruben completes the installation. The breathers are connected by a common vent tube routed over the top-rear section of the block and down in front of the starter, right alongside the stock vent hose.
Photo 13/13 | 014 Just Venting Cummins Tappet Cover Gasket | The blown-out valve-cover gasket on the 5.9L powerplant was caused by excessive blow-by pressure. Installing the new breathers should also eliminate this from happening in the future.