I always seem to be low on engine coolant

I had I looked at by my local mechanic shp and they said it needs a new heater core and quoted me $1069. From another opinion do you think a busted heater core breasonable for a 93 truck with 105,000 km on the clock? How difficult are they to change my self?

To get an idea of what you'd be getting into , try youtube for heater corereplacement (type in your exact model), and also I've seen referenced many times on this site , try 'alldatadiy.com'. Not free , but may have some very worthwhile info for you , to help in your decision.