Hello all and welcome to my next problem, I have yet to even drive my nitro car around yet.
If you get it driving within the first two weeks of owning it, you've done better than most folks. Took me a month before I could drive mine (of course I broke my con rod and could not find another one).
Regarding your problem:
1. Removing/inserting the glow plug is not going to hurt.
2. Are you 100% confident the glow-plug is coming "loose". In other words, you tighten it, and then after a short peiord of time it is loose?
3. Does the car start? i.e. When is the fuel coming out? When it is idling, or when you pull the cord to prime or start?
4. Have you checked the bolts on the cooling head? If you've taken it off, have you perhaps lost a shim?
5. If your not 100% confident it's from the glow plug hole, have you checked the tubing on the carberator? Have you ensured the HSN is not loose (it happened to me on my Losi).
6. Is it a new or used car?
If you have the ability to post a video of the problem, please do so....it will help us troubleshoot immensely.