Weird Chocolate milk oil, Opinions?
 

I recently just finished up building my 1.8 engine and turboing it.

So i drove the car on the first day and everything was great. I put 15 miles on the new engine and it ran beautifully once i straighened out my base tune.

I took it out this past Saturday for the second drive because it was a nice day and i figured it would be a great day to go out and break in the new engine. On my way home after about another 20 miles the engine started knocking :crx: so i limped it home and based on the knock i could tell that i had spun a bearing in cylinder 1. So i jacked the car up and pulled the engine out again. On the engine stand i drained the oil and it looked like really milky watery oil. I had seen oil before from a bad headgasket and this just didnt look like it had coolant in it.

So what i think happened is that after i did the first drive i swapped out the hose that connects the PCV on the valve cover to the manifold. The hold was much more plyable. When i got home before i pulled the engine i noticed that that hose was suctioned flat so that no air could get through at all from the valve cover. (the other side of the valve cover is open vent with a small filter). I think that the combustion gases were building up in the casing and causing the oil to retain all that nasty stuff that catch cans usually catch and thinned my oil out enough to cause me to spin a bearing.



What do you guys think? i would really like to get some other opinions on this.

base tune needs more straightening.

I dont think my tune is wat caused the failure or the issue

Post the .msq of your tune.

i will post it up once i get home, i am still at work now. The only other thing i can think of is that somehow coolant got into the oil but i had replaced the head gasket with a brand new one. Are there any other major ways coolant can get into my oil as quickly as it did besides just through the head gasket? (if that was the issue)

I have to rebuild it all anyways now, the crank and the connecting rods are being dropped off tomorrow to be ground and honed

Oil cooler

hmm thats a really good point, i have not yet taken the oil cooler apart, maybe it is possible that however it separates the coolant from the oil could be spent. I will also take a look at that once i get home tonight.

Thank you for the help. I will upload my MSQ soon

I've not known a factory oil cooler to ever fail so I would still guess head gasket, but you asked for possibilities. Another place is a rusted through cylinder wall.

I had one fail. First thought was head gasket too. Threw a hail marry and pulled the oil warmer. Sure enough there was a hole in it.

Duly noted.

i did a few tests on the oil cooler and it doesnt seem to have any faults with it unfortunately. i have a small jug of the oil i pulled from the car sitting to see if there is any separation with it. it is very watery and like i said earlier it is brownish like chocolate milk.

I also brought home a machinist straight edge from work today +/- .0005 overall length. the head and the block are both within spec on warp. i started with a .004'' shim and could not fit it anywhere then dropped down to a .0025'' shim and still could not fit it anywhere.

So now that i know that both the head and the block are flat within the .004'' spec that is allowed and i also know that the oil cooler is not leaking coolant anywhere. could it possibly be that if i put the headgasket on and blocked a coolant passage my mis installing the gasket that it could force coolant through to the cylinder?

I am sorry i cannot figure out how to attach my msq file here. i though i could zip the file and copy it here

A leakdown test would have been a good idea, but it sounds like you've got the motor apart already, so it's a bit late now.

Post photos of the block/head surface?

A blocked coolant passage wouldn't cause it to leak into the oil. If the head gasket was fine and the oil warmer was fine, then the next candidate I can think of is a crack in the block or the head.

--Ian

.003" warp will pop the HG in a heartbeat, first time it gets even a little hot. MLS gaskets require that the cylinder head be flat by all reasonable measurements (think <0.0005"). Just because it's within factory specs doesn't mean it won't break.

Chocolate milk = coolant in the oil. If you want to be certain of this, pay Blackstone $35 or so for them to analyze it and tell you exactly how much coolant is in your oil. It might be time to pressure-test the head and block.

One possibility since you said you just put this motor together:

The holes that the head bolts thread into, they are usually dirty/rusty just below where the bolt stops threading in. So if you "rebuild" the engine, skimming the deck of the block or head, or both, and then reassemble, the bolts will have to thread further down into the block before they "bottom out" on the head. When they hit the debris/rust/whatever just below where the threads previously stopped, this causes friction which you measure in ft*lbs when you're torque the head.

Thus it is possible the head gasket failed because of this. You just need a high quality metric tap (whatever size it is, I forget) and chase the threads. Also make sure you're torquing it to the correct spec, I use 60 ft*lbs total, in 20, 40, 60, check all the bolts at 60, if any move recheck all bolts.

Also head has to be more than just flat, it has to be smooth. If you can feel the machine edges with your finger nail, it's not smooth enough. Surface roughness (RA) should be as low as possible for MLS gaskets, I usually surface to <10 RA on my head/blocks, but anything below 40 is probably good enough.

I will get some pictures up of the head and block surface up so you can take a look at them. Ill snap some pics of the oil also. The machine shop that will be doing my crank and connecting rods can probobly do a pressure test on the head and block as long as they are not too backed up with work.

I head is very smooth and block is as well. I am very meticulous with the cleaning of it. I scraped all the residue from the head gasket with a razor blade. Once the crud is all off i go over the surface of the head and block with a machinist stone lightly with wd40 as a lubricant to take off any high spots.

All evidence so far says that there is definitly coolant in my oil (because of the consistancy and the color). So the only things left are that the head gasket didnt seal of there is a crack in the head or block. I did spend time looking it all over for any cracks and could not see any, possibly inside a water jacket could be cracked?

Possible but not particularly common.

As Pat pointed out, debris can accumulate in the bottom of the head bolt holes causing the bolts to bottom out prematurely. Similarly, decking the block and head can allow the bolts to go deeper, possibly into rusted or blocked threads.

Stock head bolts do stretch and can become longer if overtorqued. Do consider investing in ARP head studs as an upgrade. Studs have some beneficial attributes over bolts in this application. Do not torque stud nuts to values included with instructions. Torque to factory specs.

Thanks i will grab a tap today from work and go through all the threads. I did have arp head studs in the car so i dont think that the bottoming out of the bolts could have caused that issue.

Sorry for not saying that in the beginning post.

Here are the mods i had on the car
FM2 No electronics kit
ACL race bearings
Eagle Rods
ARP Head studs
ARP main Studs
OEM Pistons
MSPNP2 management
and the motor is 95 1.8

The torque spec from ARP is said to be too damn high and can cause head failure according to someone on this forum (I cannot recall who to footnote it).

I do remember seeing that, ARP calls for 80ft lbs of torque on those things, I used 55 when i put my engine back together. I have been on the forum for a while i just never really posted. You guys have everything covered on here.

Another thought i just had was even though the turbo is brand new, maybe the seal that separates the water and oil could be bad when they assembled it? That would cause a pretty big leak i would imagine.

I'm not sure that's really a "seal". I think the center housing is cast/machined with two openings in it, one for the shaft/bearings/oil, the other for the water jacket. It could be cracked, but if so it's pretty easy to test.

--Ian