Correct Head Gasket Installation?

[got boost?]

I recently had both heads off of my motor to diagnose a problem. They were reinstalled with factory head gaskets using some installation instructions I thought were a little odd compared to gas engines.

My Haynes manual says to torque all bolts in the proper sequence to 20-ft/lbs. then to 50-ft/lbs and finally to turn all bolts an additional 1/4 turn. Wouldn't it be more accurate to finish this effort with a specific torque?

I also did not use any type of sealant like Coppercoat, etc. Should I have used something?

I believe I might have a leak between a cylinder and water jacket because I have some excess oil coming through the CDR into the inlet and turbo. The diaphram in the CDR seems fine. I also seem to have a leak at the rear main seal that was not present before and have lost some coolant but cannot find any visable leaks.

All this to say that I think I must not have done something quite right and need to pull this thing down again.

What do you guys think?

[patrick m.]

all most all manufactures use a starting torque, and finish with a degree value, this eliminates improperly torqued bolts due to friction between the threads causing the "torque" value being achieved before the proper "clamp" value.
as for your coolant loss, if you had combustion gasses going into the cooling system, the coolant would forced out.
I dont know what your original problem was, but if it were, overheating, or coolant loss, or something of this nature, you may have a cracked head
good luck

[got boost?]

Patrick,

The original problem was thought to be a valve train noise and turned out to be 2-warped exhaust manifolds. I had the heads Magnafluxed, surfaced and a valve job done with new bronze guides installed. The motor had about 120K miles at the time but since it has been run on synthetic lubricants since about 6K miles all cylinders still had very obvious crosshatching marks throughout entire length of cylinders.

Are you saying that an increase in crankcase pressure would not be brought about by a blown head gasket?

[patrick m.]

If combustion was leaking into cooling sys, this would cause excess cooling system pressure, over powering the pressure cap, and venting your coolant and combustion gasses.

if the coolant is getting into the crankcase, i dont believe you would ever see an increase in crankcase preasure, however, you would see the oil level rise and become very thick. it wont turn into a "chocolate milkshake" like a gasser will.

Most shops with an emission "sniffer" can use it to detect combustion gasses at the coolant filler.

You can also have a sample of your oil tested for contaminants.
Both of these tests will give you the confirmation you either want or dont want.

good luck

[got boost?]

Patrick,

Is it not possible for a cylinder to draw water into it during an intake stroke if the failure is between a water jacket and cylinder? What if the gasket failure is between cylinders? Would this cause an increase in crankcase pressure?

If none of these senarios are legitimate, what should I be looking for to have increased my crankcase pressure?

I suppose the amount of missing coolant (about 1/2 to 3/4 of reservoir) could be due to air in the system now leaving after running about 3K miles?

[patrick m.]

if a cylinder draws coolant in, the eng will not turn, as liquid cannot be compressed. After a while, the pressure in the cylinder will force the liquid back out, and depending on piston location, the engine may then crank.
If a head gasket leaks between two cylinders, the result of pressure being forced back and forth across the deck will cut the block and probably the head at the affected area, just as a cutting torch cuts steel.

If high crankcase pressure is a problem in your engine, the dipstick will be "pushed" off of its seal with the tube, and the crankcase will vent.

[patrick m.]

I see in the list of mods you have that you have a high flow air filter (as i do). Keep in mind, the CDR valve uses the vacume created by the turbo pulling on the air filter to draw vapors from crankcase, and too keep crankcase pressures in check.

Air pockets in cooling systems are always a concern. I have found that my '95 does not give me any trouble "bleeding" the air out.

The best thing to do, may be to take an oil sample and have it checked.

[cruzer]

Hey,Got boost?. I recently rebuilt my 6.5. IIRC.
not all but a couple of the head bolts require sealant on the threads,also you should replace the bolts w/new. They are torque to yield.

There's a recent post post on the CDR valve. Check it out, it may answer your leaking seal
question.