How to improve this code with memory leak in nodejs with zlib?

I have problem with memory leak in nodejs when I added gzip support. I have wrote some code for tests. In code below I use zlib and I don't know why I have memory leak. How I can improve this code to avoid memory leaking ? Anybody can help me ?

var 
zlib = require('zlib'),
crypto = require('crypto');

var cacheList = {
  article: {},
};

  var timeoutId1, timeoutId2

  console.log('process.pid: '+ process.pid);

  clean = function()
  {
    var time = new Date().getTime();
timeoutId1 = setTimeout(function() { clean() }, 5000);

var countDeleted = 0;

for (id in cacheList.article) {
  if (cacheList.article[id] && cacheList.article[id].timeExpire + 5000 < time) {
    delete cacheList.article[id];
countDeleted++;
  }
}

console.log('deleted: ' + countDeleted);

}

  run = function()
  {
var time = new Date().getTime();
timeoutId1 = setTimeout(function() { run() }, 5);

var md5 = crypto.createHash('md5');
md5.update('' + time);
var id = md5.digest('hex');

//console.log('id: ' + id);
var text = id+id+id+id+id+id+id+id +id+id+id+id+id+id+id+id +id+id+id+id+id+id+id+id +id+id+id+id+id+id+id+id +id+id+id+id+id+id+id+id +id+id+id+id+id+id+id+id +id+id+id+id+id+id+id+id +id+id+id+id+id+id+id+id;

zlib.gzip(text, function(err, result) {
  if (!err) {
      cacheList.article[id] = {
      timeExpire: time + 10000,
      data: text,
      datagzip: result,
    };
  }
});

}

  timeoutId1 = setTimeout(function() { run() }, 3000);
  timeoutId2 = setTimeout(function() { clean() }, 5000);