I have a 1985 Volvo 240 with 165K. As a new Volvo owner, I recently experienced an oil leak due to back pressure from a clogged flame trap. The pressure blew out the cam seal and sprayed hot smoking oil all over the back of the engine compartment. I immediately stopped driving the car, replaced both the flame trap and cam seal and cleaned off the external oil with an engine cleaner. At the same time, I replaced the old oil with a synthetic. This appeared to fix both the leak and the cause of the leak. The car has run fine for 300 miles, but now will not start. The electrical and starting systems appear to be functioning properly. I was unable to jump start the vehicle. The starter turns over strong and the battery appears to be fine.

My intuition tells me that this is may be related to the previous problem rather than a new problem. I have heard that synthetic oil can expose even small leaks in the engine seals. Are there any common scenarios where a leak in the engine seals could cause the car not to start? What other symptoms should I be looking for? Any advice would be appreciated as I am still pretty new at this.