Can I simply silicone jets in a tub to seal them completely, so the jets don't leak? It's for a rental unit I own, bathroom on 2nd floor. Don't want to tear out the bath tub or ceiling on Main floor.

When you installed the new jet, did you install a new gasket on the wall fitting or use 100% RTF type silicone?
In order to seal a wall fitting that is cracked an leaking, the replacement must have either the gasket or silicone to seal the wall fitting against the wall of the tub or it will leak when filled with water.
Rod
U S Parts Center

The problem is likely the hoses behind the jets. It depends how much of a fix you want and if you intend to use the jets at a later date? If you gave the bath a good clean, you could stick duct tape over the jets as a temporary solution. If you want to use the jets again, filling them with silicone will make that impossible.

One other solution would be to make an inspection hatch in the ceiling of the living room and fix it from underneath. Cut a neat hole in the drywall making sure that you are between the floor joists. Fix the tub and screw the drywall back in place to wooden blocks screwed to the side of the joists. Then put decorative molding to cover the cut lines. Paint the water damage with PVA Wood glue as a sealer, let it dry and then paint.

Help in the link

https://www.google.com/search?q=jetted+bathtub+leaking+through+ceiling

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You need to use clay party to seal around the fitting

see this causes and fix it. God bless you
Drain Pump If the washer is leaking water the drain pump might have a hole or crack. Or, the bearings might be worn out. Replace the drain pump if it is leaking water, they're not repairable
Tub Seal and Bearing Kit If the washer is leaking water the tub seal and bearing might have a tear or rip and is letting water leak past. The tub seal and bearing can be replaced. This is common and relatively easy to replace.
Tub Seal Kit If the washer is leaking water the tub seal might have a tear or rip and is letting water leak past. The tub seal kit can be replaced. This is common and relatively easy to replace.


Tub Seal If the washer is leaking water the tub seal might have a tear or rip and is letting water leak past. The tub seal can be replaced. This is common and relatively easy to replace.

Tub to Pump Hose If the washer is leaking water the hose from the tub to the pump might be split or torn. Don't try to cut off the bad piece of hose and stretch it to fit the pump, this will put strain on the remainder of the hose and may cause a sudden and complete failure of the hose which will dump potentially hundreds or thousands of gallons of water onto the floor because the next time the washer tries to fill all of the water will end up on the floor and so the washer will never shut off the valve. Any time there is a damaged hose, replace it completely with the OEM part.

Washing Machine Fill Hose If the washer is leaking water, check the fill hoses on the back of the washer, this is the most common place for water to leak. If the washer still has the original black rubber fill hoses replace them with stainless steel or some other, more durable hose.

Drain Hose If the washer is leaking water check the drain hose. The most common places for the hose to spring a leak is from the connection to the pump out to the back of the washer. Another common occurrence is when the washer gets pushed too far back against the wall.

see this causes and fix it. God bless you
Drain Pump If the washer is leaking water the drain pump might have a hole or crack. Or, the bearings might be worn out. Replace the drain pump if it is leaking water, they're not repairable.

Tub Seal and Bearing Kit If the washer is leaking water the tub seal and bearing might have a tear or rip and is letting water leak past. The tub seal and bearing can be replaced. This is common and relatively easy to replace.
Tub Seal Kit If the washer is leaking water the tub seal might have a tear or rip and is letting water leak past. The tub seal kit can be replaced. This is common and relatively easy to replace.

Tub Spin Seal If the washer is leaking water the tub spin seal might have a tear or rip and is letting water leak past. The tub spin seal can be replaced. This is common and relatively easy to replace.
Tub Seal If the washer is leaking water the tub seal might have a tear or rip and is letting water leak past. The tub seal can be replaced. This is common and relatively easy to replace.

Tub to Pump Hose If the washer is leaking water the hose from the tub to the pump might be split or torn. Don't try to cut off the bad piece of hose and stretch it to fit the pump, this will put strain on the remainder of the hose and may cause a sudden and complete failure of the hose which will dump potentially hundreds or thousands of gallons of water onto the floor because the next time the washer tries to fill all of the water will end up on the floor and so the washer will never shut off the valve. Any time there is a damaged hose, replace it completely with the OEM part.

Washing Machine Fill Hose If the washer is leaking water, check the fill hoses on the back of the washer, this is the most common place for water to leak. If the washer still has the original black rubber fill hoses replace them with stainless steel or some other, more durable hose.

Drain Hose If the washer is leaking water check the drain hose. The most common places for the hose to spring a leak is from the connection to the pump out to the back of the washer. Another common occurrence is when the washer gets pushed too far back against the wall.

If the toilet to the floor flange wax seal is leaking that is your problem, it's your trailer. Most likely it would have leaked, but since there was no blockage, it just kept going down. Now you have blockage either in your system, or in the park's sewer system. You said you had your main drain jet sprayed, did that help or for awhile? Depending on how many bathrooms you have, usually in a trailer the main drain is near the main bathroom. If you have sewage backing up in your tub, then the whole line is backing up. If you have a long run under the trailer before it goes into the ground, make sure it is open and enough fall. If it's in the ground, then it's the park's problem. Have the park clean the line from where you connect. Any neighbors ahveing problems? Does your sewer line go to a septic tank or a treatment system.

The jets have a nut on the back of the jet. I hope you have access or else you will need to pull the tub for this job. Loosen the nut and squeeze aquarium grade silicone in between the tub wall and the nut, Tighten the nut, but not to tight. Let set over night fill and check for leaks the next day.

the tub inside has a crack,it happens time to time.you must replace unit.

Is it a jetted tub, or a air bath tub with holes or jets in the floor? If it has holes or jets in the floor, the control box is bad and needs replaced. If it is a jetted tub, there may be a water level sensor, if so the sensor may be bad causing the tub to turn on.

It's very rare, but the front water pan could have a hole in it.