Vanamamalai Perumal Temple, Nanguneri, TN - main deity is self-manifested God Vishnu !!

Vanamamalai Perumal Temple, Nanguneri, TN just dialin
Vanamamalai Perumal Temple, Nanguneri, TN tripadvisor
 This more than 1000 plus year old Vanamamalai Perumal (Vishnu) Temple, also known as Arulmigu Sree Vanamamalai Totatri Perumal Temple, Nanguneri (Tirunelveli Dist.), TN,   one of the 108 Divyadesam shrines,  is a famous Hindu temple dedicated to the god Vishnu.   Located  on the banks of Thamiraparani river this historical temple was glorified in the Divya Prabandham, the early medieval Tamil canon of the Azhwar saints  including Nammazhwar from the 6th–9th centuries AD.  Here, Perumal's consort  Lakshmi was born as Varamanagi and, it is believed,  God  married Varamangai (thayyar), the daughter of the pontiff of Vanamamalai Mutt; she took the avatar here to cleanse this place of  bad odor and pollution caused by two demons who were put to death by God Vishnu.  Built on a land covering 5 acres of land  by the Pandya kings with additional contributions from later rulers of Madurai Vijayanagara kings and  Nayaks, on the festival days devotees throng this holy place.  Sacred tank: Setru Thamarai,; sthaviruksham (tree): Mango.
Tamil nadu: Tirunelveli Dt. Nanguneri location map  www.mapsofindia.com

The temple has two prakarams (covered  prathakshana path) and various pillared halls. Vanamamalai Perumal is seen seated on the Adisesha, the serpent. Sridevi and Bhoodevi, the two consorts of Perumal are seen on  his either sides  in the second  prakara. The  festival hall in the second  prakara   is an important one
Vanamamalai Perumal Temple, Nanguneri, TN.inspirock.com
Vanamamalai Perumal Temple, Nanguneri, TNinspirock.com
The special aspect of this temple is it is a sanctified shetram  
with presiding deity being  a suyambhu moorthy - self-manifested.  
Of the eight, one is in Badrinath, North India. Daily abishekam/thirumanjanam  is done to the moorthy with Gingelly oil, a rare tradition among Vishu temples.   Seven other temples  are Srirangam Ranganathaswamy temple, Bhu Varaha Swamy temple, and Tirumala Venkateswara Temple in South India and Saligrama, Naimisaranya, Pushkar and Badrinath Temple in North India.  Temple celebrates 12 annual temple festivals and among them, the most interesting one is chariot festival (Tamil month of Chittirai (March–April).   Vanamamalai  Perumal who is believed to have appeared before Garuda and Adisesha (serpent), is worshiped during  the six kala puja. This temple is being managed by a private Mutt - an ancient srivaishnava mutt established by Ponnadikkal  jiyar on  the orders of Manavla mamunigal. Ponnadikkal  jiyar was the first and foremost disciple. It is is one of the most important mutts of srivaishnava sath sampradhayam. Vaiksana Agama sastra is being followed.
Vanamamalai Perumal Temple, Nanguneri, TN flicker.com
Brhamananda Purana, Skanda Purana and Narasimha Purana carry details about the deity here.  Scholars say that Sage Narada came  to  know about the features of Thodatri and Sargunamangai from God Shiva.  The legend has it that  Lakshmi, god's consort is believed to have born at this place as Srivaramangai (meaning woman)  and later married him. The place is referred to as Varangunamangai.  Adisesha, the serpent  upon whose coiled bed God Vishnu takes ananthasayanam and his vahana - mount  Garuda did penance to be in the shadow of the lord. Garuda became the guard of vaikuntha,  the abode of of Vishnu.
Vishnu is considered as alankara priyar (one who is fond of decoration), and Shiva as abisheka priyar (one who prefers daily ablution/ anointing). But,  here Perumal needs Nithya abishekam, a rare puja ritual.
Vanamamalai Perumal Temple, Nanguneri, TN just dialin
Once  a childless king Karya worshiped God  Vishnu who advised him to visit  Nanguneri and dig at a particular spot. Upon digging, he saw blood oozing out and to stop it he performed special puja with oil everyday  at that place.  Blessed with children, the ruler, as a gesture of  gratitude, built the temple in that place. The Gingelly oil daily being used here for  thirumanjanam/abishekam  is stored in bottles  to be given to devotees  and it has medicinal cure.
Inside this temple, there is an oil well of 25 feet depth  and 15 feet width. The well doesn't have water but has vegetable oil, presumably abisheka oil. It is said  it cures many diseases.
The deity here holds Pryoga Chakra and whoever prays to this chakara , will be free from enemies.
Stone inscriptions in this temple throw details on gifts from Sundara Pandyan I (1236), tax collections by Kulasekara Pandyan I, gifts from  Sudara pandyan II (1984) and Vikraama Pandyan III (1299). The temple, for sometimes, was under the rulers of Vijayanagara and of Travancore state.   In 1447, the temple came under the control of Vanamamalai Mutt and  consecration of the idol was done by pontiff from Tirupathi. Earlier,  Namboodris  had the rights to conduct pujas there.  During 1794, the Nawab of Carnatic, Abdul Umra, endowed extensive lands to the Mutt.

Vanamamalai Perumal Temple, Nanguneri, TN. en wikipedia org.
The major festival - the twelve-day Brahmotsavam is celebrated during the Tamil month of Thai (January - February). It is one of the temples where you can get the  Aathma Gnanam (Self-realization), Aathma Arul (blessing) and Aathma Bhakthi (blissful devotion)and the entire self  cleansed and  a visit to this quiet temple is a good bet. Certain historical temples provide us a chance to  achieve this self- purification for blissful spiritual life. 
.https://en.wikipedia.org/wiki/Vanamamalai_Perumal_temple
https://www.divyadesam.com/hindu/temples/vaanamaamalai-temple.s html