TURBO QUESTION

[TAG]

HEY GUYS - 95 LD K2500 T.D - WAS CHECKING K&N AIR FILTER YESTERDAY & GAVE TURBO A SPIN LIKE I ALWAYS DO WHEN I HAVE INTAKE TUBE OFF. ACTUALLY HAD TO TURN HARD ON IMPELLER NUT TO GET IT MOVING. ONCE MOVING FREED UP SOME. RAN ENGINE WITH TUBE OFF - IMPELLER WAS SPINNING. NO SIDEPLAY OR ANYTHING ELSE. THEN NOTICED ON WAY HOME WHINE FROM TURBO TOOK A LOT MORE THROTTLE BEFORE I COULD HEAR IT & A LITTLE MORE BLACK SMOKE ON HARD PULL. ALMOST FEELS LIKE BEARING SLUDGED UP. TRUCK HAS 175,000 MILES, NEVER BEEN APART FOR ANY REASON. HAS KENNEDY EXHAUST, HEATH BOOST CONTROLLER, HEATH CHIP. TRUCK HAS HAD OIL CHANGES NO MORE THAN 3500 HIGHWAY MILES SINCE 92000 MILES - ROTELLA T-1540 ALWAYS. ALWAYS IDLE FOR MINUTE BEFORE SHUTDOWN. CAN TURBO REBUILD KIT BE HAD OR IS COMPLETE REPLACEMENT REQUIRED. ANY IDEAS ON SOURCES & APPROX PRICES? THANKS FOR ANY HELP.

[DennisG01]

"Heath boost controller"? You don't mean the Turbo-Master, right? If you don't have the Turbo-Master, what about leaking vacuum lines? Maybe someone else can chime in with more info...

[TAG]

YES - TURBO MASTER, SORRY COULDNT THINK OF NAME.MAIN QUESTION IS IF THE STIFFNESS IN TURNING THE IMPELLER WAS NORMAL. FROM MEMORY SEEMS LIKE ALWAYS IN THE PAST YOU COULD SPIN THE IMPELLER WITH YOUR FINGER & IT WOULD COAST FOR A WHILE. NO COAST NOW AS IT IS QUITE TIGHT.

[markrinker]

Sounds like bearings are toast. With that many miles, its probably time for a new or rebuilt GM-8, which will spin up faster and flow better than your old GM-4 anyway. Don't wait for the turbo to fail and send shrapnel through your motor!

[DmaxMaverick]

Don't throw away that turbo, yet. If the rest of the turbo appears good, the bushing cartridge can be replaced inexpensively, either by a shop or yourself.

Your condition sounds like oil coking has occured. This happens when the engine is shut off while the turbo is still hot enough to cook off the oil that remains in the bearing. A short idle period before shutdown, after a hard run will usually prevent this. Fueling/boost mod's can increase the amount of heat your turbo will be exposed to, increasing the chances of coking. Dino oils (and so-called synthetics) are more sensitive to coking than true synthetics.

My suggestion is to change your oil, using a quality true synthetic 15-40, like Mobil, Amsoil, or Redline, and run normal. Check the turbo at regular intervals (every 500 miles or so, more often at first) like you did when you discovered the problem. You may find that the bearing will clean itself up and continue to be fine if you take caution and manage the heat, and cool down when necessary. If it does free up and you notice no side play or contact of the impeller with the housing, the turbo should be OK.