OIl leak comes and goes? (ford taurus V6)

[Ecomike]

I have had two odd overheating and one overlapping oil leak/overheating problem before, one was my jeep Wagoneer, 1987 that baffled me for me years.

But now I have an ever odder one. Anyone ever had a rear main seal leak about a coffee cup of oil per minute rate, like a faucet, after a long freeway drive, and then be leak free for weeks, alternating back and forth over 4-5 months?

I am fighting this on a front wheel drive 96 Ford Taurus. 3.0 V-6 Vulcan engine.

I do not believe the RMS is bad, if it was, it would leak all the time, IMHO. I am suspecting an intermittent

1) crankcase pressure build up (PCV valve and hoses just replaced) and

2) or exhaust leak blowing on the block that comes and goes, super heating and thinning the oil, perhaps due a failing engine mount and leaky manifold to pipe donut connection? It is not gas in the oil.

All 4 cat converters are less than 3 months old and replacing them solved a miss fire OBD MIL and the engine runs like new now with new Cats. Tail pipe exhaust is good, no blockage...

My 97 Jeep Wagoneer turned out to be a bad donut on the Exh manifold to down pipe flange blowing on the oil pan to block area.

Muffler shop guys passed all three vehicles as leak free, and they were wrong on the first two.

 

[Digger87xj]

Re: OIl leak comes and goes?

Taurus engine was known for breaking a rear main bearing cap bolt.

 

[Alaskan89XJ]

How does that happen?

Bad line-bore of block? Bad crank-counter weight? Too high, or too low compression to rod, to crank right there to rear bolts causing hammering, or stretching of one side, or the other bolt to break?

 

[TRCM]

Never had any issues with the one in my 93 mercury, and I put over 230k on it......that was a tough lil motor

Did have a harmonic balancer come apart and mess up the timing cover for me @ ~ 150k.

that thing would till spin the tires on the 1-2 shift, and it was in the heavier station wagon

 

[Digger87xj]

How does that happen?

Bad line-bore of block? Bad crank-counter weight? Too high, or too low compression to rod, to crank right there to rear bolts causing hammering, or stretching of one side, or the other bolt to break?

I dunno.

We'd pull them to fix a rear main leak and find the cap of the bolt in the pan.

only one, IIRC it was always the right side. Never caused any other damage..just leaked oil.

Crappy part of the taurus you had to pull engine/trans combo out with the cradle. First time doing one in an indy shop was a mess.

 

[Ecomike]

Re: OIl leak comes and goes?

Taurus engine was known for breaking a rear main bearing cap bolt.

What symptoms would that create?

This engine runs like a new engine, smooth as glass, from idle to max rpm (rev limiter is about 3800-4000)

Also when the oil leaks, it seems to leak some everywhere, not just the RMS

 

[Digger87xj]

probably not your issue... just threw it out there as a fyi

Comes and goes, leaks from everywhere... speaks PCV system fault to me.

 

[Ecomike]

probably not your issue... just threw it out there as a fyi

Comes and goes, leaks from everywhere... speaks PCV system fault to me.

THANKS!!!! We did replace the PCV valve and vent hoses, and started babying the RPMS and freeway speeds ( keeping it down around 2000 rpm, instead running it like a race car (my son is still in that fast and furious mode when late for work, LOL, in his 20s).

No oil loss or leaks since we did both. But it did throw a cyl #6 miss fire code 2 days ago. Cleared the code, and it has not returned yet. Still in the plug and plug wire test plan mode.... I cleaned and wiggled the plug wire....before clearing the code....planning to run injector/throttle body cleaner in it to clean the valves.......seats etc....May need to check compression on #6, but it runs like a new engine, and the head work is less than 12 months old...

Cyl 6 is on the passenger side, not the tranny side of the block. It also the cyl we had a miss fire on before we finally replaced all the blocked 250,000 old cat converters that were coated with dried up coolant from prior head-head gasket problems the last 100,000 mile and 8 years that we have had it.