Equilon Lubricants and Cummins Engine Co. say they're closer to a solution to a seal problem caused by extended-life coolants (ELCs) that we reported last week. In the meantime, they say it doesn't make sense for Cummins owners to drain the coolant.

The ELCs in question are organic acid types manufactured by Equilon and sold under various brand names, including Texaco Extended Life Coolant, Cat Extended Life Coolant, Shell Rotella Extended Life Coolant, and Detroit Diesel Power Cool Plus.
The companies have differing views on the extent of the problem. Cummins says the coolants cause degradation of silicone seals in its engines around 80,000 to 100,000 miles.
Cummins had initially recommended that ELC coolant in existing engines be drained and replaced with a conventional heavy duty coolant. But the company now says that "may not be necessary or helpful at this time" because it will not remedy the situation.
Cummins has continued to ask all truck manufacturers to stop factory-filling all Cummins engines with ELCs.
But a July 16 statement from Equilon recommends continued factory-filling of all engines except the Cummins N14. Equilon says the problem is confined to the N14 rocker box seals on a limited number of trucks.
The companies are expected to issue a joint release within the next few days, which will provide a recommended course of action for users of Cummins engines filled with ELCs. One possibility is an additive that would use silicates and other additives to help neutralize the problem.