my suburban is a 6.5L diesel that i just bought and dont know much about. when starting cold the truck starts right up no problem but anytime after it is warm it cranks for a long time before it will start. and twice now it took me almost 10 minutes to start it. it just cranks and cranks. now it currently did it to my gf and i think she burnt out the starter now so once i replace that where should i go with the long crank starts?