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Replacement parts for FRIGIDAIRE PLD2855RFC0 Frigidaire/dishwasher | AppliancePartsPros.com

Sometimes it is just the nuts have loosened or cracked. They are very cheaply made. See NI in the parts at the bottom of Section 3 in the parts.

Carefully check around the heater terminals in the tub just to be sure that the tub has not cracked.
Check that the rubber washers on the heating element are still flexible.
I do not see them as a separate item but hopefully someone else will jump in with a part number if they need replacing.

Remove the heating element and re-install it. Clean the rubber washers. If it has been leaking for any amount of time there will be calcium deposits between the tub and the washers that will have to be cleaned up before trying to re-seal it.

If the washers are not available as a separate item you may as well try tightening it more as it is going to cost you a new heating element in any case.

[COLOR="Blue"]1. Do you know if the elctrode connectors to the heater are the clip-on type that you just pull off or there's some kind of a release? Any instructions on how to disconnect them[/COLOR]?
Do not know and could not find any info that says there is anything special about the connectors. Take a close look at them perhaps there is a little lever/tab that has to be pushed to release the connectors.

2. If the washers are not available separately from Frigidaire, can't they be replaced by other ordinary rubber washes?
If you cannot find them sepeately then you may have to use rubber washers though I do not know how they will stand up to the heat. I did find the following for a Whirlpool unit, they do look close to yours in size re: each square is 1 inch.
Part number: AP2920722