Hi everyone. Looking to purchase a '93 f350 dually 7.3 IDI. It has 250k on it, seller said the engine and tranny were replaced before(he has no proof, though). When i remove the oil cap or oil dipstick, i see zero blow by. I even put my hand over it and felt no air coming out. Should i also remove the CDR tube and check there? Truck has no problems, except for hard cold starting issues. Seller says the truck is very hard to start if it sets overnight without a block heater. With a block heater, he says it will start in 3 cranks. When it starts, there is greyish, black smoke for a minute, then when it warms up it dissappears. Seller wants $1800. Does that sound like excessive blowby, or is that just glow plug, injector or fuel line air seapage problems? Should i buy the truck? I can handle fixing it. Interested in knowing anything else pertaining to inspecting this truck the best i can. Thanks!