My 1995 Ford Escort blowing out blue smoke a minute into startup

I had a oil change a couple months ago. Not due for another 3000 kms. I topped up my gas tank the other day and put fuel injector cleaner into the tank. Would that possibly solve the problem?

Fuel injection cleaner or any other additives will not repair blue smoke out of the tailpipe. Blue smoke is evidence of oil burning/consumption. If they used the correct oil viscosity when you got your oil change, then see my below response.

My mechanic said to use 10w30 for my car since it is an older car (1995). Haven't had any problems with the switch. Have used that type for a couple years. What would the cost of the repairs be to fix issue as mentioned in your reply? Is it worth fixing?

Typically we go by what the specifications on oil viscosity. But it seems everyone has a different school of thought on that. As far as a cost goes for cylinder head work, it is hard to know 100% until the cylinder head is removed and inspected. If the cylinder head is removed for inspection and probable repair, it is the time to do the timing belt and water pump because they are fairly accesible and the timing belt is partially removed when then cylinder head is replaced. That being said an approximate cost for removal and cylinder head work, timing belt and water pump can be in the range of $1800-2100. It is hard to say if it is worth it. It really depends on the condition/service history/miles of the vehicle. When determining if it is worth it cost wise, it is also important to consider if you had to purchase a new/used vehicle and what you would be paying nor that versus repairing what you have. A big decision for sure.