6.5 optimizer swap, blows blue smoke on one side...

[Husker6.5]

I could swear that my '94 didn't have them when I had to put two new heads on. Pulled the block heater on the driver's side (had to any way, it had burned out) to drain it, but looked and didn't see a pipe plug. Didn't pull the starter to look behind there on the passenger side, after pulling that head, used the shop vac to suck the water (with a wee pinch of antifreeze in it, remember the saga of valve seat cracks WITH GM's "miracle cure tablets" added to it and going through 8 gallons of water in 60 miles? [Warning to Neal who insists the tablets will fix his head/head gasket leak, they don't. They just prolong temporarily the inevitable and expensive cracked head replacement.] I pretty much had straight water in the system.) off of the piston heads and out of the cylinders. I pretty much had straight water in the system by that point, anyhow. I haven't looked at my '98 to see if there are pipe plugs in the block for draining. Perhaps somebody could post a definitive (by block casting number/model year) listing of which 6.5's have block drain plugs and which ones don't? Or am I just becoming a senile, blind old man who couldn't see the obvious block drain plug 6" away from the block heater I was removing from the frost plug hole 10 years ago!

 

[ak diesel driver]

If the shoe fits . Lol

 

[Husker6.5]

Where'd I leave that damn shoe?

 

[EWC]

In front of the drain plugs ?

 

[Ba_051]

Well I pulled the heads and guess what? No bad head gaskets... No cracked heads... No cracks in the block... Had them pressure tested and they are good. The only issue there might be is the precups, they are actually loose and I can gently tap them out from the injector hole... Other than that, the heads are perfect... No cracks anywhere. Even the precups dont have cracks...

Only thing I can think of is when the pushrod was bad, The excessive compression caused the head bolts to stretch and loose the clamping force just enough to allow exhaust gasses to enter the cooling system... But I did not get any pressure in the cooling system... This is just really baffling... I flushed the cooling system 3 times and after 2-3 days of driving (60 miles per day) it was black again...

I let the liquid evaporate and all that is left is a very fine dark brown dust very similar to the soot left in the exhaust pipes, but not super black like the soot is, just very dark brown...

 

[Husker6.5]

Sounds like the finely ground walnut shell powder that is the "secret ingredient" in GM's cooling system stop leak. Seriously. PO may have had a small head/gasket leak and dosed the shit out of the system before finally fixing it. That stuff would be in every nook and cranny of the entire cooling system.

 

[Ba_051]

Yea, good possibility. granted I am the first civilian owner. Not sure if the military uses that stuff. Either way, Its getting ARP studs and felpro gaskets... Ill flush the crap out of the system once its back together.

 

[Will L.]

While its apart, hot tank the heads to get them clean as possible. Maybe the radiator as well.

Are you going to do stuff to the lower end while your at it like new bearings and rings?
I thought about doing gapless rings when I Had my engine out last time and regret not doing it so bad....

 

[WarWagon]

Well I pulled the heads and guess what? No bad head gaskets... No cracked heads... No cracks in the block... Had them pressure tested and they are good. The only issue there might be is the precups, they are actually loose and I can gently tap them out from the injector hole... Other than that, the heads are perfect... No cracks anywhere. Even the precups dont have cracks...

Only thing I can think of is when the pushrod was bad, The excessive compression caused the head bolts to stretch and loose the clamping force just enough to allow exhaust gasses to enter the cooling system... But I did not get any pressure in the cooling system... This is just really baffling... I flushed the cooling system 3 times and after 2-3 days of driving (60 miles per day) it was black again...

I let the liquid evaporate and all that is left is a very fine dark brown dust very similar to the soot left in the exhaust pipes, but not super black like the soot is, just very dark brown...

This is normal - Precups are held in by the block with a head gasket in between. I have had them fall out when I pulled a head. Since you have the heads off "just to put ARP head studs in" no reason not to send the block out to be tanked and finish off with the above advice and gapless rings.

Make sure you seal the ARP stud threads into the block with blue locktight or any other sealer except the ARP sealer garbage. They are "wet holes" and will leak coolant if you don't do something. ARP revised their instructions. Others have some wild sealing ideas like O rings. I use Red or Blue locktight depending on what's on hand and then tighten the studs into the block some. I do not expect the red will ever let the studs back out of the block...

"Well I pulled the tstat and flushed the system for about 2 hours before it ran clear... Started it up with tstat out and got no bubbles or anything..."

Clearly by this test you have no combustion leaks into the cooling system. By the amount of time to get the cooling system to run clear there is simply something in it like sat around with open cooling system for years and rusted, a massive oil cooler failure, stop leak, Dexmud, dessert sand "Marine: adapt, improvise, and overcome! Then when we get out of the s#it let the motor pool figure it out." Seriously a corrosive wiz in the radiator after taping a hose up is plausible. Beer, you name it, as sometimes engines are disposable depending on the situation.

1 box of Cascade dishwasher powder poured in, up to operating temp, cool down and then flush it like crazy.

Don't run straight water for more than 1 day for testing proposes. Aka to find leaks. Look at the somewhat rare and expensive aluminum timing cover and how hard it is to replace and imagine how fast the corrosive hard water we got out west will eat it. It has two water pump passages to the block and then a chamber with vents by the sealed coolant passage. It can be eaten up and still seal if there is enough RTV plugging the vents. Big pocket to hide junk however. (Scrap part and replacement in background.)

 

[Ba_051]

When I had the oil pan off to recover the lost pushrod, the bottom end looked perfect. I really dont have the time or funds to pull the entire front end apart again to pull the motor to rering and what not. It ran great except for this crap in the coolant... After letting some of it sit for a few days and evaporate, the residue left is a fine powdery substance that is very dark olive/brownish color...

Its getting new head gaskets and for only $100 more than tty bolts, the arp studs are worth it in my opinion. I hate TTY bolts... I was also thinking about flushing it with a gallon of distilled white vinegar to remove rust and what not, but im not sure the vinegar would be safe with the aluminum...

 

[Will L.]

Depending on what the dark olive/ brownish stuff is. I would start with dishsoap. It really sounds to me like someone ran. Staight water and let it rust up a bit and/or maybe used dexcool and it sludged nicely.

CLR works ok.
Vinegar is a mild acid that might work, but not knowing it is your trying to clean off its a guessing game if it will work. You can try it, just rinse it well afterwards.
Buy some of the $5 brush kits from harbor freight, cut of the ring end and put it in a cordless drill. Scrubbing something always does better than a simple soak.