The recipient said it had “sucked” to find the unsigned note on his vehicle. The anonymous letter writer criticised the man over the noise made by his air-conditioning.
The man, from Ontario, Canada, posted the letter on social media site Reddit.
The letter reads: “Buddy, I’m not sure if you’re aware, but your air conditioner is not working properly. It’s loud as f***.
“It was 8C last night and the thing is still running non-stop.
“Please do us all a favour and try opening a couple of windows once in a while.
“Fix your damn air-conditioner or lose some f** weight so you’re not so hot all the time!
“Can’t even hear my Goddamn TV it’s so loud.”
A neighbour, who did not want to be named, told Chronicle Live: “He’s always got different flags but that is the first time I’ve seen a Nazi flag. I’m in complete and utter shock. I’m disgusted.”
Another resident, who also did not want to be named, said: “Other neighbours are as disgusted as I am. It gives the street a bad name as we’ll all be tarred with the same brush.
“Walker is a lovely mix of people so there will be a lot upset at seeing this bigoted flag.”
Mr Brown said he was in the British Army for six years and served in Germany.
He claimed he put the controversial Nazi flag up for a relative who was interested in history and World War 2.
Mr Brown said he checked online to see if Nazi flags were banned before flying it in his garden.
The pensioner said he then made the decision after checking they were legal.
A retired shipyard worker, Mr Brown said: “I was a bit concerned I would upset people. I was worried with it being a dodgy flag – and it doesn’t get much more dodgy than that. If it had been banned I wouldn’t have done it. I’m going off what somebody said on the computer.”
He explained how he is in the habit of flying flags and recently raised that of Sierra Leone. But he said he would not fly a Union Jack due to the state of this country.