I have noticed that many cans of pepsi don't have a hechsher (kosher symbol) on them. Do they need one?
The Kof-K gives the hechsher on Pepsi. I have spoken to them and they said the following: the syrup used is all under the certification of the Kof-K. Certain bottling plants have a mashgiach on premises and products which come out from that facility have a kosher symbol on them.
Other plants don't have a mashgiach on premises and the products that come from these plants don't have a kosher symbol. These plants still use the same kosher syrup and therefore, many rabbis hold that it is 100% ok to drink those products. This is because the syrup is kosher and the machines only deal with cold products and never hot ones.
Consult your Rabbi about what you should do.
I thought it was Rabbi Zevulun Charlop who gives the certification. Regardless, yes Pepsi is certified, but no the symbol is not on the label.
Most of the major American brands are certified, but often the mark is not on the label. Here's a list, courtesy of kashrut.com and the cRc.
If a soda is totally uncertified, it's generally not recommended. Too many colorings or flavorings that could pose a Halachic problem. (Atlanta's Rabbi Tobias Geffen was famously involved in a reformulation of Coca-Cola to make it kosher, 70+ years ago.)
This answer comes from a Chof-K publication- Halachicly Speaking:
Pepsi® without a KOF-K It is common to purchase a Pepsi® product without a KOF-K in a vending machine. The Pepsi® syrup and the bottling plants are under two different hashgachos. If there is no KOF-K on the cap or label then the KOF-K does NOT recommend it.
I think The answer is Pretty clear YES
Just as an added point to illustrate the problem in Uman, they used to drink Coca Cola and they find out that they where putting in wine (THATS RIGHT WINE!!!) as The coca cola company adjust the taste to the preference of the country,and Russians like wine so they where drinking Yayin Nessach and such it may be Halachicly not a problem Just Know BUYER BEWARE!!