mexicanfooddude
Registered User
Hello helpful oil burners forum folks,
My ‘83 F250 with the 6.9 overheated last week… no warning, and I was going freeway speeds so unfortunately didn’t catch it until I looked in my rear view mirror to see a trail of steam/smoke behind me, looked down to see that the temp was redlined and the overheat light was on, and then the truck simultaneously shut off. Took about an hour for it to get cool enough for me to touch anything.
Once I could, I found that the lower radiator hose was disconnected from the radiator, but I imagine that it blew off as a result of overheating, and was not the cause. I reconnected the hose, and filled it back up with coolant - no leaks while the truck is off at least. Tried to start it and it turns over but doesn’t even utter a cough of trying to catch, even with a light spritz of starter fluid.
I know these diesels need 4 things to start: air, heat, fuel, and compression.
Started by taking off the air filter just to rule that out. No start.
My glow plug system hadn’t been working for the month or two prior to this overheat (cracked pigtail in the wiring harness, not getting power), so I stuck a heat gun into the intake for 10 minutes to preheat things. I imagine that on a 75 degree day that should have taken care of heat - still no start.
I trickle charged the batteries overnight - no start. They had certainly been seeing some extra use during the month or two of no glow plug system prior to the overheat, however it would eventually start every time until this occurred. Perhaps the battery cables got damaged during the overheat, or the batteries coincidentally got too strained after the last no-go-plug-start, and the starter isn’t getting enough juice? I imagine I can test this at the starter… I read something about seeing a minimum of 10.5 volts at the starter while cranking, is this correct?
As for fuel, I opened the shader valve on the fuel filter and had a steady stream of fuel coming out while cranking. I also pulled the lead off the fuel shutoff solenoid with the key in the ”on” position and reattached - I heard the click of the solenoid and saw a faint spark when reattaching. I haven’t cracked the injectors to check for fuel when cranking (no sign of leaking fuel at them at the moment) - is this a good next step for diagnosing a fuel delivery issue?
If all else checks out, I imagine that a compression issue would be a blown head gasket or cracked head. Anything I can do to diagnose that for sure?
Thanks for the help in advance!
My ‘83 F250 with the 6.9 overheated last week… no warning, and I was going freeway speeds so unfortunately didn’t catch it until I looked in my rear view mirror to see a trail of steam/smoke behind me, looked down to see that the temp was redlined and the overheat light was on, and then the truck simultaneously shut off. Took about an hour for it to get cool enough for me to touch anything.
Once I could, I found that the lower radiator hose was disconnected from the radiator, but I imagine that it blew off as a result of overheating, and was not the cause. I reconnected the hose, and filled it back up with coolant - no leaks while the truck is off at least. Tried to start it and it turns over but doesn’t even utter a cough of trying to catch, even with a light spritz of starter fluid.
I know these diesels need 4 things to start: air, heat, fuel, and compression.
Started by taking off the air filter just to rule that out. No start.
My glow plug system hadn’t been working for the month or two prior to this overheat (cracked pigtail in the wiring harness, not getting power), so I stuck a heat gun into the intake for 10 minutes to preheat things. I imagine that on a 75 degree day that should have taken care of heat - still no start.
I trickle charged the batteries overnight - no start. They had certainly been seeing some extra use during the month or two of no glow plug system prior to the overheat, however it would eventually start every time until this occurred. Perhaps the battery cables got damaged during the overheat, or the batteries coincidentally got too strained after the last no-go-plug-start, and the starter isn’t getting enough juice? I imagine I can test this at the starter… I read something about seeing a minimum of 10.5 volts at the starter while cranking, is this correct?
As for fuel, I opened the shader valve on the fuel filter and had a steady stream of fuel coming out while cranking. I also pulled the lead off the fuel shutoff solenoid with the key in the ”on” position and reattached - I heard the click of the solenoid and saw a faint spark when reattaching. I haven’t cracked the injectors to check for fuel when cranking (no sign of leaking fuel at them at the moment) - is this a good next step for diagnosing a fuel delivery issue?
If all else checks out, I imagine that a compression issue would be a blown head gasket or cracked head. Anything I can do to diagnose that for sure?
Thanks for the help in advance!
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