SuperDave
Full Access Member
I just bought an 89 7.3 service truck that has been sitting 18 years due to a bad torque converter. I got the thing to run fairly easily and all was good until I started trying to trace a misfire, i decided to run a compression test and one cylinder came up slightly lower than the rest and was making a spitting sound through the intake. Next I decided to do a leakdown test and that particular cylinder would after several seconds start making bubbles in the radiator. I'm assuming it's a gasket issue or a head issue because it bubbles air out slowly no matter where in the cylinder is in the bore, the first time I applied air tho the cylinder the pressure pushed the piston back to BDC so I rolled it back to TDC and held it with a breaker bar, same slow bubbling. It couldn't be a huge leak because it's only about 30% leakage. I'm just trying to prepare myself before I tear it down, it will be a shame if the engine is junk because it starts easy, runs good has great oil pressure and doesn't smoke. Also the oil is clean, no water/coolant in it.