Diesel Experts 93 GMC 1 Ton, 6.5 Turbo Diesel Fuel Problem
Posted in Ignition Systems | Asked on Aug 5, 2010
I have a 93 GMC 1 ton with a 6.5 L. Turbo Diesel. Upon starting when it’s cold, it billows white smoke…and lots of it (yes I let the glow plug light go out first). Even after warming up for quite some time, when I get it on the road, it is a bit jerky when accelerating as if it’s not getting fuel and it still blows white smoke. This mellows out after about 5 minutes. One last thing, even when it’s hot and I am running down the road at a consistent speed (i.e. 45 mph), it will start to feel as though it is sputtering. Are these problems all related, and if so, what could it be? I’ve changed the fuel filter and checked the easy glow plugs (the ones under the turbo are much more difficult to access.)
Thanks for your help!
There are 2 Answers
As a Diesel mechanic, lots of white smoke even when its not cold outside will sometimes indicate a coolant leak internally. you might have a cracked head, blown head gasket, or otherwise. if youre mechanically inclined, you can do a few checks.
1. Block tester – you can get these from napa for like 20-30 bucks. it looks like a big tube that you jab one end into the coolant reservoir, and fill the other end up with the supplied special fluid. you run the truck until its at operating temp (thermostat opens) and if fluid changes color and/or you get lots of bubbles, you got a cracked head or bad head gasket.
2. coolant pressure tester – pressurizes the coolant system. you will be able to see if the system is losing pressure somewhere.
3. look at the under side of your oil fill cap and your coolant pressure cap. are they milky sludgy looking? if so, you have a problem.
4. Take it to a mechanic. They can do a cylinder cut-out test. Turns out, if its not coolant related, you just might have a bad injector. they will be able to tell you.
hope this info points you in the right direction.
i thought about it… the older 6.5 diesels had problems with the holes for the headbolts not being machined depp enough, and the bolts would loosen , causing cracked heads, etc. I ve worked on enough of these, and most of it was head work. Take it to a shop and let them test the engine. If they determine that the head is cracked , your good, that job is around 1000$. Lets hope its not a cracked block, which is common out of those boat anchors. The next step if its not the long block is to startchecking the fuel system.