Tentoestobz

First time doing heads/cam swap on a car. Working on a 2008 z06. This has been a real treat lol.

Got the car assembled and loaded base tune, car ran and drove fine. Did not do any hard driving, maybe revved to 3-4k a couple times to try to find any leaks. Noticed oil leaking near balancer, so I went back in and replaced the oil pan gasket and front cover gasket using sac city tool.

When I pulled the oil pan to replace the gasket, I noticed some swirling in the oil that remained in the pan. Thought it may have been from the heads dumping coolant into oil passages when I removed them the first time. Reassembled everything and after driving 15 or so miles and not seeing any leaks around the front main seal, I decided to dump the oil to look at it. Full of coolant - not milkshaked, but definitely swirled up. No evidence at all of oil in the coolant or coolant reservoir.

Thought I must have done something wrong installing the heads or had a head gasket issue. Removed both heads. I noticed on the passenger side head, the top 5 small head bolts were not as tight as the drivers side were. There is a .000001% chance I didn't torque them properly the first time. I just know I followed the torqueing procedure with all brand new ARP bolts. The middle row of larger bolts were all tight, but when I pulled them out they all looked wet, like with coolant, not the ARP assembly lube. Every one of them. The bottom row of larger head bolts were tight and only had the ARP assembly lube on them. Did not have the same wet appearance as the bolts nearest the top of the cylinders.

I inspected all of the sleeves and saw no cracking. Saw no cracking on the deck. Heads are brand new texas speed heads, saw no evidence of cracking anywhere. I poured water in these bolt holes that I noticed the wet bolts were removed from just to see if one or any leaked down over a day. Didn't see any less volume, maybe a bad test as the engine was cold but figured worth a look. Took special care to clean out the bolt holes, reasseblmed everything.

Started it up and idled about ten minutes,dropped oil. Looks like a lot of coolant swirling in the oil still. Maybe it's the remnants of the coolant/oil mix that was still in my oil cooler? I did not drop more oil than I filled the car with. I put about 7 quarts in. When I dropped the oil about 5.5 came out of the pan drain plug holes. So it's not like I put in 7 quarts of oil and dropped out 8 or 9 quarts of oil/coolant mix.

I'm thinking I must have cracked the block when I tightened down the heads the first time, like I didn't get all of the water out of the head bolt holes. Had no issues with torqueing them down, didn't hear any popping noises or anything the first time. I chased the threads with an ARP chaser/used brake clean and vaccummed them out, but didn't shoot compressed air in the holes to ensure they were dry.

Is there anything else I can check or something obvious I'm missing before I have to go down the road of replacing the block? New to this stuff, any input is appreciated.

ClothSeats

Is the coolant level dropping in the coolant reservoir?

Tentoestobz

I have driven the car very little throughout this whole project. Have not noticed the coolant level dropping drastically the two times I have had the cooling system filled and operating properly. Never saw the reservoir suspiciously low, but haven't had the car running many times to notice.

ClothSeats

Maybe you could do a coolant pressure test to get some immediate information. It should tell you if there is a leak or not, but won't tell you where the leak is.

torquetube

I would do the pressure test if only to get a sense of the speed of the leak. What prep work was done to the deck surface of the block? Which head gaskets are you using?

ClothSeats

Or a pressure test might show that there is no leak at all. Instead, the coolant must have gotten into your oil in the form of some leftover when torn apart. A long shot, but a pressure test is cheap and easy to do now, and once you take the engine apart again it's too late.

Tentoestobz

I didn't sand the deck surface or anything. Cleaned up any obvious gasket material by hand, used a razor on some spots and rubbed it with a towel and brakeclean. They all felt smooth to my finger. What is the best method for ensuring they are clean?

Used new stock GM head gaskets both times.

HK770

copy/paste

But lubrication on the bolt threads—and a whole host of other factors—can cause fluctuation in torque readings. So once you add a lubricant of any kind to the threads, all bets are off as to whether the same torque setting will truly secure the bolt.

Tentoestobz

Are people running ARP head bolts dry? Are we thinkng my head gasket is potentially over or under compressed and causing the coolant to slip past? Thanks

sleepingcougar

ARP manual doesn't say anything about lubrication of the head bolt thread.

torquetube

It certainly does. From your own attached PDF:

ARP specs their assembly lubricant for pretty much every critical torque application. GM goes about it differently by using TTY bolts.

Chatman

How do you know your torque wrench is accurate?

Tentoestobz

great point. Through my frustrations I’ve purchased a straight edge and a snap on torque wrench.

I did a cooling system pressure test and I noticed a lost a couple psi of pressure over 15 minutes. I am not sure that I had the cooling system purged of air thoroughly though when I preformed this test.

Dumped and refilled engine with oil. Idled about ten minutes. Was noticing the exhaust didn’t smell right. Usually it smells pretty rich like gasoline, instead it was smelling different, I’m assuming I was smelling some coolant burning. Had some whiffs of smells around the front of the car like maple syrup. Once the coolant got up to about 170 degrees I started noticing very faint smoke coming from the exhaust so I turned it off and dropped the oil. Still seeing some milky oil. Also noticed what looked like the faintest amount of oil in the coolant, first time I’ve noticed this in the coolant reservoir at all.

I’m going to pull the heads again and check these brand new PRC heads with the straight edge to make sure these things are flat. Going to check the deck surface as well. Going to put it back together again with new gaskets and new torque wrench and see if I have the same issue.

Maybe in a pessimist but I don’t see how this block isn’t cracked. I’ll be extremely surprised to pull the heads and put them back on and have a different result. Oh well I’ll throw another 200 bucks of gaskets and oil at it before I pull engine.

Dads2kconvertible

If you do a compression test or leakdown test that might narrow down your search for the problem to one or two cylinders.

jonjoy

when you buy ARP studs they give you a small tube of their torque lube, don't they supply it with their bolts?

bignikmusic

if you cleaned the block holes then they are probably not the issue, unless you missed one or something. I would check the block is flat and look closely and make sure you got the correct gaskets and try one more time. if you are pushing coolant its probably a gasket issue not a block issue especially if it was fine before.

Budarooski

Good point. Back in the late 90's I was building a motor for my Mustang and while torquing the heads I ripped the threads right out of the block due to a cheap torque wrench (read WAY too low...75lb was probably 110lbs...stripped the bolt right out of the block).

grinder11

Just a thought......Are you certain the heads blind hole threads for the studs/bolts was totally clean/blown out before you assembled everything? If you don't ensure all coolant and oil is removed and blown out with compressed air, you can crack the bottom of the blind hole, which may, or may not, lead to coolant traveling up the bolt or stud. Also, for accurate torquing, check with ARP for their latest advice. I say this because when I installed my LS7 heads, their procedure had changed. They recommended NOT putting the assembly lube on both sides of the flat washer, only on the nut side, IIRC. This was because some were actually pulling/stripping the threads from the block, even when still under the torque spec. Also, when you call, make sure you know which ARP fasteners you have. ARP 2000, regular ARP, and another series which I can't remember at the moment. Even though I followed their procedure exactly, I experienced what they were saying. No damage, but at one point at around 50lb/ft the stud nut turned a good 30°-45° without getting tighter!! Their lube is almost too good!! Also, IIRC, you dont use the lube on the studs threads that go into the block. Just finger tighten them until they stop turning. Hope this helps......

Tentoestobz

I've done a pressure test with a handpump in the coolant reservoir. It drops from 18lbs to about 15lbs over the course of half an hour. I did a leak down test on all of the cylinders and all of them were close to perfect. I put 90psi in each cylinder at TDC or close to it and the lowest one read 88lbs. Put new MLS headgaskets on, sprayed them with copper spray this time, why not lol. Third set of head gaskets I've put on this thing. Used a calibrated snap-on torque wrench to put the heads on. Followed the ARP instructions to the letter. Checked the deck and and heads with a mechanic's straight edge to check for flatness with a flashlight. Heads and decks all looked perfect. Drove it 20 miles, no smoke coming out of tailpipes. Not seeing coolant level dropping at all, and also not seeing oil level rise on disptick in the sump. I dropped the oil, looks bad. All swirled up. Doesn't smell like gas, tried to light it on fire and it just puts the fire out. Spin a stick in it and it looks like a science project.

I'm out of ideas. Anybody got anything?

grinder11

Do you have an engine oil cooler in the radiator? I'm guessing you don't. If you did, oil under pressure would probably find its way into the coolant. That doesn't seem to be happening. Most times oil doesn't get into coolant because coolant is under pressure, and the oil is just sloshing around in the pan. So it is usually coolant getting into the oil, as you're experiencing.

EDIT!!!!!!! I re-read your post and see you DO have an oil cooler!! Is it in the radiator? If so, that could be the issue. However, it still doesn't explain coolant on the studs/bolts.....

I'm suspecting you have a small, damn hard to find, crack. Either in a sleeve or a cylinder head. That or there is some sort of porosity problem. NEITHER will be easy to find. I wish I could be more helpful. Are you running OEM LS7 head gaskets? I ask because I have heard of a problem every once in a while with Cometic gaskets seeping coolant. It's not common, but it has happened more than once or twice. I feel for you, brother, I really do. This is nobody's idea of a good time!! Best of luck to you......