I can't figure this POS out. I just resealed it for the third time in a year the other day. First time It was leaking coolant from the front header gasket real bad so I took the cooler off my wifes truck and rebuilt it and put it on. It leaked oil something fierce from the front header as soon as I started it. So I took it back off, covered the front gasket in gray silicone and it stopped.

A couple weeks ago it started leaking again on cold mornings. Same exact place. The back edge of the front header flange.. I just took it off again, cleaned the crap out of it and the flanges, made sure there was no corrosion or pits that could cause it and that they were flat, I cleaned up the old original front header and installed it and everything was fine for a few days till I left it parked outside last night. This morning when I started it up oil started dripping out of the front header gasket again on the back edge of it.
Does anyone have any ideas because I'm about to light a match under it.
Oh, we only got down to 28 degrees last night and I have fresh motorcraft 15w40 and a fl1995 filter in it. The only thing I can figure is my oil pressure is really high. what can cause this on a 250,000 mile motor.

 

Oil pressure is all that I could think of also or your somehow pressurizing the system too much.. Have you checked oil pressure with a mechanical guage on the HPOP rez?

 

no. I don't have a mechanical gauge but the one in the dash is in the same place it always is. This is just too weird. Man I have resealed crap on nuclear reactors before and never got my tail whipped like this. I checked those flanges and cleaned them really good. New ford gaskets and everything. I even went so far as to do a dye penetrate crack test on it all. No cracks that I could find.
It's got to be something weird with that front engine cover flange. I just got back to the house and I think after it cools off I'm gonna slightly loosen the 2 bolts and retorque them again. Just to see what happens. I'm at a loss.

 

In that rear header there are two valves. Ones a bypass and ones a relief valve right? which one is which? I think the bypass is the one you can see with the filter off. I know it's still there but I didn't check to see if it moves this time when I had it off. I didn't mess with the rear header at all. Just cleaned it off and put a new gasket on. if one of those is sticking on cold mornings could it cause this?

 

the oil pressure switch trips at 7psi IIRC and drops to the center of the guage. It will not show true oil pressure unless you get a sender from an older truck(1980) and bypass a resistor on the guage.. Then your guage would read correctly.. I think your right on the bypass being the valve you see with the filter off.

 

Since you used the front header from your wife's truck, I will assume that there is nothing wrong with the header.

I think you may have an issue with the front cover like possibly a crack from the oil port to a bolt hole boss. If there were a seal problem, I would go as far to say that you'd be more likely to have a coolant leak as it is less viscous than oil.

I have done dozens of these and have yet to see a repeat header flange leak front or rear. To go even one step further, I have never done an oil cooler because of a flange leak....it's always been the core.

 

That's my problem. I've done more of these than I can count and never ran into this crap. I did check that thing for cracks though. I cleaned it off real good after spot blasting it and did the dye penetrant test on the header and the cover flange. I've never had that stuff miss a crack before. I was a nuke welder so I thought I was good at this. You should have seen me hanging upside down in the engine compartment with my headlight on looking for the crack.
I think at this point I'm just gonna finish rebuilding my 97 engine and swap them out. This one has some serious miles on it anyway. If the front covers were interchangeable I'd do that but they aren't.

 

Why aren't the front covers interchangeable? We put a '97 front cover on Cody's '94.5 or early '95 whichever it is. Either way, it went on and works just fine.

 

I thought the antidrainback valve was in the pump on the 97 and in the front cover on the 94. I could be wrong.

 

This is true, but that doesn't mean you cannot use it. If you use a '96+ front cover, you need to have a '96+ HPOP, HPOP gasket, and rez. If you try to use the '94.5-'95 pump or HPOP gasket, it will not work.

 

yeah that's true. I'm not throwing any more parts at this motor though. I got the 97 powerstroke on the engine stand now and getting ready to go through it. This is gonna cost me. It will NOT leak though when I'm done for a long time. And it's gonna have a pair too. I'm not messing around anymore.