the "other" coolant caused misfire?!?!
#1
01-03-2006, 11:21 PM
the "other" coolant caused misfire?!?!
I've been searching half the night for info on what is supposed to be a documented coolant caused misfire in a 5.4, especially on cyl. #6.(NOT 4)
In this senario the wall thickness in the head at the valve seats, (or seals, I'm not sure), is too thin and wear will cause tiny pores to leak coolant into cyl. causing misfire. The solution is removal and dismanteling of head which is then welded and R&Rd. I am a mechanic and heard this story first from a manager of a local Precision Tune, and then from my company's tech support. I have a customer's 2000 expedition in the shop now with coolant on plug #6. Has
anybody heard of this and is there a miracle in a bottle that might fix it without a teardown?!? (My tech support guy says no to the miracle)
In this senario the wall thickness in the head at the valve seats, (or seals, I'm not sure), is too thin and wear will cause tiny pores to leak coolant into cyl. causing misfire. The solution is removal and dismanteling of head which is then welded and R&Rd. I am a mechanic and heard this story first from a manager of a local Precision Tune, and then from my company's tech support. I have a customer's 2000 expedition in the shop now with coolant on plug #6. Has
anybody heard of this and is there a miracle in a bottle that might fix it without a teardown?!? (My tech support guy says no to the miracle)
#2
01-04-2006, 07:44 AM
#3
01-04-2006, 08:57 AM
Logistics Pro
I'm a little rusty on the 5.4L, having owned a 7.3L psd for a while after the '02 F150 I had.
IIRC that usually happened because of the coolant hose going over that plug (if I remember correctly which spot the #6 cylinder is) developed a small leak and would short out that cylinder. However, it wasn't enough of a leak to be easily found due to what ever coolant that had dripped evaporated by the time you inspected the cylinder.
I've heard of something similar happing to 7.3L PSDs caused by cavitation due to the coolant not having the proper amount of SCA's, but never on a gasser motor.
IIRC that usually happened because of the coolant hose going over that plug (if I remember correctly which spot the #6 cylinder is) developed a small leak and would short out that cylinder. However, it wasn't enough of a leak to be easily found due to what ever coolant that had dripped evaporated by the time you inspected the cylinder.
I've heard of something similar happing to 7.3L PSDs caused by cavitation due to the coolant not having the proper amount of SCA's, but never on a gasser motor.
Last edited by superrangerman2002; 01-04-2006 at 09:00 AM.