I've dug myself in a huge hole. My problem started with a pegged oil pressure gauge, easily replaced and all was well for about two weeks. Then, my pressure started falling until it was barely present at stop lights and the dreaded red light started appearing. I hit the internet to find out what besides an oil pump might be causing my problems and the idea of worn bearings was tossed about. I went through the pains of dropping the upper oil pan and checking the main bearings and decided to swap out bearings due to visible (but not horrible) wear. Short and sweat, I got into the "since I've gone this far" syndrome, pulled the engine, and replaced everything except the piston rings because the car had great compression. Here's my issue: I upgraded to Juke bolts which requires drilling out about 1/4" and bottom tapping for each head bolt. In every step of building this thing I followed protocols to a "T". I'm going to spell it out in case I did something wrong. This upgrade called for tightening all bolts in sequence to 30 ft. lb., then +100 degrees, and then loosening all in reverse sequence. Tighten again to 30 ft. lb. in sequence, then +95 degrees, then +95 degrees again. I used ARP Ultra Torque Assembly lube, which is supposed to give the most reliable torqueing. This differs slightly from stock head bolts which only require two turns of 90 degrees after torqueing to 30 ft. lbs.. For those wondering why I would do such a thing, these bolts are supposed to be adequate for small turbo upgrades, and I thought it would be wise to take care of this step while I had it apart.

For several weeks I was watching closely and everything was fine. I got very comfortable since it was running well and began to have confidence that it was put together correctly. One day I was completely ignoring the gauges and talking to my wife on our way to a wedding. On the expressway the car suddenly became sluggish and lost power, and after looking at the gauges I saw that it was overheated. Of course I pulled off the road, but the damage was done. Once the car cooled down and I added coolant it ran fine for about 20 minutes and then overheated again. It is clear now that I either have a failure at the head gasket or worse, I've cracked the block or heads. (Can't run without overheating and steam at the tailpipes after 20 minutes every time.)

So here's where I'm at. I'm pulling the engine again. I purchased a new (used) set of heads that I've checked and verified are straight (not warped) at the mating surface. Once I pull the engine I'll make sure the mating surface of the engine hasn't warped, and if not I'll go through the bottom end again and check the cylinder walls for cracks. If my heads aren't warped or otherwise damaged I'll reuse them, otherwise I'll use the new set that I've purchased. When I reassemble, am I missing something when I torque the heads? I'm wondering if it is possible that one of the taps went into a water jacket? To address that concern should I use thread sealer rather than torque lube? Is there a way to ensure the head bolts are torqued equally (in terms of ft. lbs. and pressure) after following the protocols? Is there a known ft. lb. torqueing spec that I could use rather than the pressure + angle method?

If anyone has had similar issues and found a resolution please let me know. I guess it's possible that I just got a lousy set of head gaskets, they weren't OEM, but I'm a little skeptical of the pressure + angle method of torqueing at this point. Any info would be appreciated.

 

Welcome and sorry to hear about your engine woes. It's clear that your rebuild has a large coolant leak somewhere and you'll need to do some detective work during the second teardown. Like you, I suspect that large a leak has something to do with the use of the Juke headbolts. I'm wondering where did you find this suggestion? The OEM VQ35DE headbolts typically have plenty of margin unless you are going for a FI or high compression application. My first suggestion is one you may not like: you need another set of eyes to do this teardown and critically examine where the failure is. I'd suggest a local machine shop or engine builder to do this job, and be prepared to invest in another shortblock if needed.

 

Its sounds that you haven't took the engine apart yet. If you do look closely if you can find what the cause of your problem is. A blown headgasket is not always the fault of the headgasket.
But did you bleed the engine correctly after assembling it?