That's following the mid-air panel blowout on a MAX 9 model operated by Alaska Airlines earlier this month.
No one was seriously hurt in the incident, but it raised new concerns over how well the planes are made.
MAX jets were previously grounded following two fatal crashes that were traced to a design flaw.
On Monday, Boeing said it would deploy a team to Spirit AeroSystems, which makes the fuselage part that blew off.
The team will also inspect other points in the manufacturing process.
Customer airlines will also be allowed access to conduct their own inspections.
The actions come after the U.S. Federal Aviation Administration extended a grounding of MAX 9 aircraft.
One hundred and seventy-one of them will now be out of service until further notice.
The FAA says it will make a decision after 40 of them have been thoroughly inspected.
Earlier, the regulator said it could bring in an outside body to take over some inspection responsibilities that were previously assigned to Boeing.
Alaska Airlines welcomed the steps taken by the company.
There was no comment from other carriers, including United, which have seen jets grounded.
