ORIGINAL: yakfish

An engine being new really has nothing to do with whether or not it will have a leak. traxxas isn't really known for their high quality control standards.Exactly, that's why you see thousands of threads saying how poorly their stuff has been put together out of the box, highly unlikely especially with the TRX engines.Again there are thousands of people out there that have zero issues with TRX engines and only a handful that post threads about TRX engines failing when it turns out the operator was the cause of the failure. I didn't say all the TRX engines had air leaks when they are new but there are without a doubt several that come brand new that do, and there have been and will be several threads on these forums complaining about tuning issues with the TRX engines. the majority of people who have some experience with nitro engines much preffer other brands over the TRX engines because of these tuning issues.
I have had a few 3.3's and a 2.5's and they had air leaks even the new ones.So why did you not bother to call Traxxas and send it back??? A brand new mill should NOT have leaks especially the TRX engines since they use o rings for gaskets. If I can fix a problem myself and avoid waiting for customer service I will. but your right... a new engine "SHOULD NOT" have an air leak.
it can be a good idea to seal and enginebefore you ever bolt it all up and run it. Yes it can be a good idea. But good luck sending it back to Traxxas for ERP with silicone sealant goop all over it. They can and most likely will refuse an ERP if they get a motor with sealant on it.
Again why mess with customer service when you can fix a problem easily yourself
I will agree that is a good idea to check for exhaust leaks and cutting some holes in you body will help keep temps down too. does the engine over heat when the body is off?