BobND
04-05-2005, 21:29
My 1994 K-10 6.5 TD has been doing stupid little things for a couple of years... little "jerks" or "stumbles" at cruise, odd occasional bursts of excessive "diesel rattle" in stop-and-go driving around town, and finally, severe jerking, overspeeding (not responding to accelerator pedal), followed by dying miles from nowhere at -10 degrees, and refusing to start. (It set a code 35.)
It DID start after cool-down, and my 5-year-old and I made it back home without further incident. (I was NOT a happy camper, though!)
I recently installed a new FSD on a commercially-made generic FSD heatsink (disappointingly small) mounted to the intake.
I tightened the famous transistor hold-down nuts, and put a dab of silcon sealant on them to prevent them from shaking loose and let it cure overnight. Then, I filled the open area around each transistor with dielectric silcone grease to hopefully aid heat transfer from the transistor cases to the heat sink. (I discarded the plastic "cups" that go around the transistors. I suspect they are there to catch the little nuts that hold the transistors in place, as if they fell off, they could cause a short between the transistor case and the FSD chassis, possibly causing uncontrolled engine behavior. IMHO, they certainly can't help with efficient heat transfer, and aren't needed with the nuts now siliconed in place!)
I did not use the Stanadyne heat transfer pad. Inside, I used silver-bearing heat transfer compound intended for use on computer CPU's.
Lastly, I carefully cleaned off the excess heat transfer compound that had squeezed out around the FSD, and then put a small bead of silicon sealant around the perifery of the FSD, where it meets the heat sink, to prevent any of the compound from oozing out and making a mess, and also, to prevent any moisture from getting between the FSD and the heat sink.
I bought the pickup with 58,000 miles (the IP had been replaced at some point by the PO), and it now has 172,000 on it.
With the new FSD, it runs SUPER, with none of the little glitches (or the big ones, for that matter). I feel that it's running better than it did over 100,000 miles ago.
However, although I've not actually checked it (gotta round up my infra-red heat gun), I don't like how hot the FSD and heat sink get sitting on top of the motor. Even in our current 50 degree North Dakota spring weather, it heats up considerably.
When I get time, I will tap and drill a LARGE generic heatsink to mount an FSD, extend the wiring, and move the unit up behind the LH headlight. Then, I'll keep the current FSD and heatsink for a spare JUST IN CASE!
It DID start after cool-down, and my 5-year-old and I made it back home without further incident. (I was NOT a happy camper, though!)
I recently installed a new FSD on a commercially-made generic FSD heatsink (disappointingly small) mounted to the intake.
I tightened the famous transistor hold-down nuts, and put a dab of silcon sealant on them to prevent them from shaking loose and let it cure overnight. Then, I filled the open area around each transistor with dielectric silcone grease to hopefully aid heat transfer from the transistor cases to the heat sink. (I discarded the plastic "cups" that go around the transistors. I suspect they are there to catch the little nuts that hold the transistors in place, as if they fell off, they could cause a short between the transistor case and the FSD chassis, possibly causing uncontrolled engine behavior. IMHO, they certainly can't help with efficient heat transfer, and aren't needed with the nuts now siliconed in place!)
I did not use the Stanadyne heat transfer pad. Inside, I used silver-bearing heat transfer compound intended for use on computer CPU's.
Lastly, I carefully cleaned off the excess heat transfer compound that had squeezed out around the FSD, and then put a small bead of silicon sealant around the perifery of the FSD, where it meets the heat sink, to prevent any of the compound from oozing out and making a mess, and also, to prevent any moisture from getting between the FSD and the heat sink.
I bought the pickup with 58,000 miles (the IP had been replaced at some point by the PO), and it now has 172,000 on it.
With the new FSD, it runs SUPER, with none of the little glitches (or the big ones, for that matter). I feel that it's running better than it did over 100,000 miles ago.
However, although I've not actually checked it (gotta round up my infra-red heat gun), I don't like how hot the FSD and heat sink get sitting on top of the motor. Even in our current 50 degree North Dakota spring weather, it heats up considerably.
When I get time, I will tap and drill a LARGE generic heatsink to mount an FSD, extend the wiring, and move the unit up behind the LH headlight. Then, I'll keep the current FSD and heatsink for a spare JUST IN CASE!