I cannot get this thing to stop leaking its oil out all over the place. Have had the oil pan re-sealed multiple times with some pretty expensive sealant, no luck. Oddly, it will only start to leak when driving at highway speeds. It doesn't leak at all (after re-sealing) around town but once on the open road for a few miles look out! I was going to buy a new pan for it but was told mine is fine...I'm starting to doubt it. Interestingly enough, it seems to really leak when the AC is on so I don't use it which sucks when its 90 outside! Can the AC cause an oil leak?? That would be odd. I'd hate to spend money on a new pan and have it not work but the way I'm putting oil in this thing the pan would pay for itself in about 2 seconds if it does work. Anyone here ever have this kinda problem with a Mits engine?? It's the 2.4L in a '95 Mighty Max.
Hmmm, a 7-bolt 4G64 with major oil leaks at highway speeds but not around town, and AC seems to make it worse. Interesting problem, with several possibilities.
Since the oil pan has been sealed, its unlikely to be that. When AC is on, there's more belt load on the main crank pulley. These pulleys are a two piece design with a rubber insert, and the pulley tends to separate with age. All this usually does is make belts squeal and causes rattles, not oil leaks. If the pulley itself is loose on the crank, the front oil seal (in the oil pump housing) could be compromised.
Check the oil pressure switch on the oil pump housing. I had a failure with oil leaking out the switch itself, but only above 3700 rpm. Around town I rarely hit 3400), but on the highway, I cruise at 4000 or lots more when passing, and the oil blew out everywhere in less than 100 km. Look for oil dripping out the terminal when the engine is running. If the alternator is covered in oil, start with the switch.
The oil filter casting is secured with 4 bolts, and a gasket to the oil pump housing. Unusual for leaks here, but not impossible.
There's other oil seals behind the balance shafts, but these rarely leak. Next to the oil pump sprocket there's a screw-in cover that hides the balance shaft bolt. There's SUPPOSED to be an O-ring behind this.
If either of the balance shaft nuts are loose, the shaft could move and oil will leak past the seal. You would normally have rattling noises if this was the case.
The cam has a seal that sometimes leaks, but this is almost always an all or nothing situation.
There's a gasket that seals the oil pump housing to the block, and there's an oil gallery up near the head that sometimes blows out, but again, its an all or nothing situation.
Lastly, the 7-bolt engines are (at least in the 2G turbos) notorious for crankwalk, but its very rare in the 4G64, and I doubt this is the problem.
What you may have to do is get the front covers off, and check where the oil is really coming from.
Wow! Thanks for the info and I hope if it's any one of your possible locations that it's a really easy one to fix. I'll be ripping those covers off this weekend to have a look-see, hopefully it doesn't explode before then driving it to work...A/C off of course. What a PITA, if it wasn't in such good shape otherwise I'da junked it....yesterday.
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