Is it permissible for a Kohen to visit the gravesite of a Sadik? Do the remains of Sadikim emit Tum’a just like the remains of ordinary people, or is there no Tum’a because of their special stature of holiness?
There are numerous indications that even the remains of a Sadik generate the status of Tum’at Met. In Masechet Pesahim, for example, the Gemara discusses the story related in the Torah (Bamidbar 9) of a group of people who were unable to bring the Korban Pesah because they had contracted Tum’at Met. (They were eventually told to offer the Korban Pesah a month after Pesah, on Pesah Sheni.) The Gemara cites one view that these people were those who transported the coffin of Yosef, and they were therefore Tameh. Yosef, of course, was a great Sadik (and is in fact referred to as "Yosef Ha’sadik"), and yet the Gemara clearly assumes that his remains generated Tum’at Met. Similarly, the Gemara in Masechet Berachot relates that as the great Sage Rabbi Yohanan Ben Zakai lay on his deathbed, he instructed that all the utensils be removed from the home so they would not become Tameh when his soul departs. Rabbi Yohanan was certainly a Sadik, and yet his remains would have rendered the utensils in the home Tameh.
Indeed, the Shulhan Aruch, in discussing the laws of Tum’at Kohanim, makes no mention of an exception for the gravesites of Sadikim, implying that Kohanim may not visit even the graves of Sadikim.
By contrast, Rabbi Shimon Bar Yohai comments in the Zohar that the Sadikim die "Mitat Neshika" (death through the "kiss" of the Almighty, as it were), and as a result their remains are free from the clutches of Satan and are not susceptible to Tum’a. The Zohar writes explicitly that the gravesites of the righteous do not emit Tum’at Met. It should be noted, however, that different versions of the text of this passage exist, and it is therefore uncertain whether this is what the Zohar actually says. In any event, there are those who allow Kohanim to at least visit the gravesite of Rabbi Shimon Bar Yohai at Meron, since according to his view, his grave does not generate Tum’a. The accepted Halacha, however, does not follow this opinion, and Kohanim may not visit any gravesite, including the gravesites of Sadikim such as Rabbi Shimon Bar Yohai, Rahel Imenu, and so on.
There is a story told of Rav Haim of Sanz (1793-1876) who once asked a student why he wasn’t going to the grave of a certain Sadik on that Sadik’s Yahrtzeit. The student pointed out that he was a Kohen, and the Rabbi noted that according to tradition, the soul of a Sadik is found throughout the city of his burial site. Therefore, there is value even to visiting the city of the gravesite on the day of the Yahrtzeit. Hence, even though Kohanim may not visit the gravesite of a Sadik, it is certainly permissible and worthwhile to visit the area around the gravesite of Sadik.
Summary: It is forbidden for Kohanim to visit graves, even the gravesite of a Sadik.
