Toyota tensioner plate replacement

I have a 1999 Toyota corolla LE with ~99K miles on it. During the recent oil change and inspection, the mechanic says “The tensioner plate on the back of the cylinder head is leaking oil and needs replacement”. What is the function of the tensioner plate and what are the consequences of not replacing it? Also how much it would cost to replace the part (parts and labour). The mechanic quotes ~$400. Appreciate your response.



A quick google search reveals it is a timing chain tensioner. I have no idea why it is a “plate” and why it has oil in it that can leak.

Tensioner plate sounds like part of timing belt but it is on front of motor so not sure what he is talking about?
Keep a check on oil level till you find out what it is.
At 90,000mi you are due for timing belt replacement as called for in manual.
When you do this make sure you also change water pump, belt tensioner and I think there is a spring also.
Most of the cost is labor to get to belt and the water pump is right there so it is always best to do both at same time.
Find a good local shop do NOT use quick lube, tire store or trans shop to do this. This point cannot be stressed enough.