I have a 1990 D150 with a 318 that has seen better days. A rebuilt 318 at around $1500 is a little pricey. What are your opinions of a used motor? Thanks for any help....OKRD

 

first thought:

what is problem with current eng?
asking because if you are capable of R&Ring an eng, maybe just a few parts (rings, oil pump, bearings) and a little guidence you could "freshen" the current eng ....cyl hones are loaner/rentals..torque wrench also.. any friends to help?

most have been both lucky and burned on used engines..

 

The motor just bellows white smoke when at idle..like at a stop light..not so much going down the road. No real work space, only hand tools, limited time and know how. I've got a good mechanic to do the replacement. I just need some help on which motor to choose.. the cheaper used motor or the pricey rebuilt motor.
Thanks for the reply..OKRD (and yes if the beer is cold I have friends)

 

white smoke?
check for coolant loss- head gasket?
auto trans/? sometimes depending on which trans- a bad vac modulator will send ATF to engine result white to gray smoke.

 

When you buy a used engine that you have not seen run you are buying another man's problems. IMHO
I don't believe you can solve a problem without knowing what the problem is. I think you need to identify the cause of the smoking problem before you spend good money replacing the engine only to find out it didn't solve the problem. How does it run besides the smoke?
1. A quick compression check is cheap and may yield the info you need to make a good decision.
2. Try opening the radiator cap, rev the engine and look for bubbles to identify a cracked head or blown head gasket or loose cylinder head bolts.
3. Get the engine warmed up, pull the dip stick. You are looking for a foaming of the oil. Now touch the tip to the hot exhaust manifold. If the oil sizzles instead of smoking you may have a cracked cylinder bore in the block.

 

try some Bars Leak for starters

 

SEAL on #2 you said to take the radiator cap off and rev the motor to see if bubbles.iso if it has the things you said for this it will bubble and if no bubbles then that stuff if good?just asking never have heard this or # 3

 

on the other hand, if the truck is in really good shape, the 1500 might be worth it...

 

#2 does not prove that anything is OK if you can't see bubbles but if bubbles are present one of those things is wrong. #3 detects water in the oil. The sizzle is the water boiling off when it is heated by the manifold because oil alone will just burn off.
Nemisis is right about the Bars leak. I have seen cracked heads go for thousands of extra miles after its use.

 

yep. on my old sidekick i even kept a bottle in the glove box in case i ever hadto pimp home (which i did)