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Old 10-03-2017, 05:39 PM   #29 (permalink)
cajunfj40
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Leak down tests are not easy on an Explorer.

Hello oil pan 4,

Quote:
Head gasket patch is what you use to get the vehicle sold.
They don't work.
It's more of a temporarily repair till you can get it fixed right. This head gasket rear stuff doesn't stop the leak, it just slows it down.
I'm thinking of it more for a cracked head vs. a blown head gasket. These Cologne OHV v-6's are apparently prone to cracking the heads (though less so on these last few years), causing coolant leaking into the combustion chamber. Symptoms are the same as a blown head gasket in that cylinder, except without the oil/coolant mix. With the other coolant leaks, there's more going on than just a crack, so I need to pull the head for sure. Any idea how much of a mess the sodium-silicate "water glass" based head gasket fix products make for the guy replacing the gaskets after it has been used? Not the drop-in stop leak goop, the stuff you have to do with water only, then flush out and replace with coolant after 2 heat cycles.

Quote:
Not fixing a bad head gasket as soon as possible will lead to cylinder wash down with coolant, which will taper it, then after you fix it you will be burning oil.
Yes, I need to fix it. Trying to figure out how much it needs so I can do the right repair at the least cost. Cost-effective, so to speak. Unfortunately there's no way to check for a cracked head until it is off, and I don't want to spend ~$500 on new heads if the short-block is bad, nor do I want to put shiny new heads on a leaky old short-block. Doing all that work and still having leaks would really make me mad.

So, still working on this thing. Drives nice when it isn't missing. Never overheats. Starts easy.

I tried to do a leak-down test this past weekend. Half a day spent swearing and getting bruised and scratched in the garage and no reliable results. I need to get at a minimum new o-rings for my cylinder adapter, as I strongly suspect I am not getting a decent seal there. The late-model 4.0 OHV Cologne V6 heads take a long-reach 14mm, with the threads in the bottom half of the well, so the regular adapter doesn't fit and my slightly longer one probably engages 2-3 turns at most.

I'll probably try picking up a spark-plug non-fouler to use as an intermediary. It will provide a taper-seat seal to the cylinder head, and an easily cleaned surface for the o-ring on the leak-down adapter to seal against. Then I can mark the harmonic balancer so I can get the engine on TDC properly for each cylinder's compression stroke. I know I got it close - I hooked up the adapter, put a longer hose on it, climbed under the truck, put a ratchet on the nose of the crank and turned it over until I felt/heard compression out the end of the hose. Then kept turning until I couldn't get more air to come out. Problem is, I believe it rotated backward until a valve opened whenever I tried to test it, because I got hissing out the intake at 15psi input on cylinders 1-3, all I had time to do. Gads is it painful to pull and replace plugs/plug wires on this engine! A/C reciever/dryer and lines plus heater lines and valve and blower housing on the passenger side, A/C lines and EGR lines/valve plus brake booster on the driver side.

Pretty sure I did confirm a connection between at least cylinder 3 and the water jacket. I built pressure in the system and pushed out at least a cup of fluid. No bubbles - just a bit of pressure release when pulling the cap and an "upwelling" of fluid.

After I ran out of time, I put the plug from Cylinder 4 into Cylinder 3 and put a new one in 4 while buttoning things up. I was just going to swap between 3 and 4 and see if the misfire moved with the plug from #3, but I preferred no miss (at least for a while) to a moved miss. Plugs look pretty evenly clean except #3, which is tannish/reddish. No fuzz, just colored. ~2,500-2,800 or so on the plugs. No oil-soaked plugs.

The possibility of a cracked head is worrying, mostly from the perspective of "if I plan to just swap the gaskets/head bolts and I find cracked head(s) I'm without a truck until I get un-cracked head(s) and find time to work on it again". Plus I can't replace the pan gasket with the engine in the truck unless I at least drop the front diff. I also don't want to put a bunch of new gaskets/new or rebuilt heads on a worn-out shortblock. Been pricing used engines locally. U-Pull is ~$260 with warranty, $160 without. Other pre-pulled yards are ~$300-$800 "ran good" or "tested" or "150 all" with 150-250k miles on them. Thinking about trying to get a shot at a decent shortblock I can tidy up in prep to swap in, and 2 more heads that might not be cracked. Any warrantied engine I get a chance to test at home and take back if it is "bad" beyond their warranty conditons.

Hard part is getting the heads crack-checked. Maybe I can get lucky and be able to pressure-test a used engine and it doesn't have blown head gaskets. I don't want to replace the head gaskets twice just to check for cracks, and if I take the heads in to get crack-checked, they need to be cleaned, and they ought to have the valves done, etc. and pretty soon why didn't I buy new heads?

This is an intentionally low-dollar vehicle. I'm paying myself in tools to the tune of what the labor estimates are to get various things done, it's the only way I can justify putting any money into it at all. It won't get a $1650+ remanufactured long block, that's for sure. A used "ok" engine, a good gasket set, pick-the-best of what I have for valvegear, manifolds and heads from the two engines, though? Maybe. Might even fool around with seeing if I can clearance an intake manifold to drop straight down over the cam sensor. Pain in the butt to have to drop it down to 1/4" off touching, then scooch it back 1/2", then drop it the rest of the way onto the thick beads of goop that seal the valley. Or use the cheaper 1-piece gasket that's got steel carriers.

Hard to justify much when there are less-rusty and more importantly less-totaled trucks out there for <$2,000. Sunk costs are going to eat me alive on this thing if I don't take a step back and make a plan. At least after the initial spend most of the cost has been tools I get to keep.
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