Water in oil after rebuild - looking for guidance

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bigtooth

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Hi all, hoping to get some help on solving the internal coolant leak I have on my magnum rebuild.

Junkyard 360, refurbished stock heads, thinner head gaskets, new timing chain cover, RPM Air Gap intake, holley carb.

Have 12* initial, motor starts and runs well. BUT, oil turned milky within the first 90 seconds of running. Have flushed it twice with cheap 10-30 running just enough each time to see cleaner oil come through the rockers.

Really surprised at only the 12 ft lbs of torque on the edlebrock intake. I'm hoping I'm only looking at intake or timing cover.
Any thoughts on diagnosing the issue before I start pulling things apart?
 
A lotta sm blocks have locator pins in the front and rear ( China ) walls.
Most alum manifolds don't have the reciprocal holes, and if the pins are not removed, can cause the manifold to "stand-off" the front/back sealing surface, not allowing the surfaces to mate .
This may allow oil and water to leak .
 
Magnum engines never used the pins on the China walls, but if the intake gaskets were not positioned correctly maybe there could still be a similar problem.

That is a lot of coolant in a short amount of time. What front accessory drive system and timing cover are you running? Was the timing cover very corroded around the water pump area before assembly?

Worst case scenario, did you accidentally run a long bolt into the wrong hole when installing the timing cover? One of the lower holes on the left front of the block can cause this.
 
Thanks for chiming in. It's a new timing chain cover.. I'm away from the motor for a few days, but I'll check the bolts. I've read of this issue but never fully understood where the trouble spot was with the longer bolts, just tried to make sure nothing was forced..

I don't remember battling any pins installing the intake. At least that's not too hard to check..
 
A cooling system pressure tester will find it in a hurry.
 
As for intake bolts
3/8ths coarse are about 25>30 ftlbs
5/16ths coarse are 18>22
The only bolts close to 12 on your engine, are the 1/4-20 oil pan bolts which are 15
I wonder if you have foot-pounds confused with something else.

Retorque as above and pressure test again.
Then if still gushing water;
Empty the pan and leave the plug out.
Take the plugs out.
Then pressurize the cooling system with air on top of the water, at about 4psi but not more than 10>12. Then I would check each hole with the piston at the bottom, to see where the water comes out.
Hopefully the cylinders remain dry.
Hopefully the water comes out the pan.
After that, it's probably a cheap fix, and the bases have already been covered in earlier posts.
When the water is finished coming out, escaping air will be your friend, just follow the sound.
 
bigtooth said:
Thanks for chiming in. It's a new timing chain cover.. I'm away from the motor for a few days, but I'll check the bolts. I've read of this issue but never fully understood where the trouble spot was with the longer bolts, just tried to make sure nothing was forced..

I don't remember battling any pins installing the intake. At least that's not too hard to check..
Click to expand...
Oh yeah, kept the serpentine system..
 
bigtooth said:
Oh yeah, kept the serpentine system..
Click to expand...
OK, cool. Maybe this will be something easy. The two bottom water pump mounting bolt holes go right into the engine through the timing cover. If the gasket did not seal the coolant would leak right into the oil pan. I am pretty sure the factory used sealant on those two bolts.
 
AJ/FormS said:
As for intake bolts
3/8ths coarse are about 25>30 ftlbs
5/16ths coarse are 18>22
The only bolts close to 12 on your engine, are the 1/4-20 oil pan bolts which are 15
I wonder if you have foot-pounds confused with something else.
Click to expand...
The Magnums have a funky multiple step torque procedure from the factory where you go 72 inch-pounds a few times and then you go 12 foot-lbs twice, all in their little sequence. The bolts and gaskets are not designed from the factory for more torque.

Which reminds me, there was supposedly a bulletin back in the early Magnum days about too much torque pulling the corners of the manifold up causing coolant leaks. Never seen it myself though.
 
bigtooth said:
Thanks for chiming in. It's a new timing chain cover.. I'm away from the motor for a few days, but I'll check the bolts. I've read of this issue but never fully understood where the trouble spot was with the longer bolts, just tried to make sure nothing was forced..
Click to expand...
This thread, post 22 shows the bolt hole that can damage the cylinder wall if a bolt is too long, and a measurement.

Uh oh, power steering bolt broke into number one cylinder?
 
I've ordered a coolant system pressure test kit, will be able to test on Friday.. I pull that bolt when I'm home on Thursday to double check the length.
 
Spent some time on the rig today. The bolt in question is 7/8" under the head and washer.. I had the coolant system pressurized up to ~ 14 psi at one point, it takes about 15 minutes to loose about 2 psi... maybe a bit quicker when warm. I did run the motor for about 10 minutes today, oil eventually turned white again and I drained it. It did seem when the engine was warm it dripped out of the pan at a quick rate till cool. Coolant level dropped by a half inch or so in the radiator.

I wish I could hear the air, but it seems the leak is a bit to slow. Though, I have yet to drain the coolant and try pressurizing the system.

Also, took the plugs out and turned the engine over a few cycles with the system pressurized, no change..

I'm thinking take the pan of next, try to spot the leak from below. Next being intake then timing cover. Rinse with diesel while apart.
 
A few thoughts to add

Just to rule out any head or head gasket issues you might want to perform a compression test.

Do you have oil and water mixed in the radiator?

If it was a junkyard motor were the heads surfaced? Maybe the intake side was not milled as well and it’s not sitting properly. Not all shops follow this procedure.

Some intake manifolds are fussy with the type and thickness of the intake gasket.

Wonder if they pressure tested the heads for possible cracks?

If the intake is not sitting properly on the head you could be getting a leak at the bottom of the mating surfaces.

If you remove the intake and it pulls right off you know you didn’t have a good seal. If it comes to that look at the gaskets to see how they crushed.

Hope it’s something simple.
 
I bought a junkyard 360 and put in same manifold and carb. I put sealant at all 4 corners of the intake and smeared some sealant around the water inlets on the heads and intake before putting on the intake then torqued to 30 ft. pounds in a chriss cross fashion. Have no problems with leaks. I hope this helps.
 
I've tracked down a couple small coolant leaks and have slowed the pressure test leak to about .5 psi over 15 minutes, but I can also see it leaking inside the passenger side from the heater core area. A drip every 2 seconds or so under pressure. If there is an internal engine leak it can't be very big (at least with a cold motor).

I've been changing the oil after running it for a few minutes each time, now on the 4th change and it seems to be staying clearer each time. The oil that is in there now I have about 10 - 15 minutes of full temp driving and the oil hasn't turned white or risen in quantity. Although, I'm still getting bad mayo in the valve covers.

I have a theory of what I did. When I first filled the coolant system, I did using straight water to check for leaks. The truck was parked at a slight upward angle. Everything filled and looked good for a few minutes till i heard water running off the back of the intake manifold down the bellhousing. I had forgotten to tighten my water temp sensor and water was running out of it. Long enough to fill the lower area of the intake and down the back of the motor. I never thought anything of it and tightened up the sensor, leak stopped. What I've thought of since then is I didn't have the distributor tightened down (clamp bolted on, but would still spin) with the intention of adjusting the timing first thing after startup.. I'm hoping I just ran a bunch of water past the o-ring into the distributor opening and am slowly working it out of the motor. I only have one vent in one of the valve covers but have some pieces on the way to setup a PCV system... I'm really hoping its just residual moister and lack of PCV is causing the mayo that is still forming..
 
That sounds like you found your problem. It takes a while to work out all the mayo in valve covers. I know your head gaskets are more than likely one and done for torque but did you retorque the intake?
 
I took them off and cleaned them once, since then more has built up. I'm planning on cleaning them again when I install the PCV. But this is the first oil change where there is no evidence of water on the dip stick after running.

I did go through and give them a little extra working in to out and criss/cross pattern.
 
I haven’t assembled a small block in years but do the intake bolts on the ends next to the water crossing pass into the valley to perhaps allow water to mix with oil?
You put sealer on the intake threads?

This of course happens do to a gasket not sealing.

Throwing it out there…

Sounds like you are going towards a solution.
 
My Magnum 318 just developed an internal leak that I'm trying to find too. I have the Edelbrock intake and LA front dress on it. As of now, I know that I lose coolant and I have mayo under the valve covers and in the PCV system. The dipstick looks like clean 300 mile oil. I've pressurized the cooling system to 13 psi (it's a Champion radiator with 0.9bar cap) and I lose about 2 psi in a half hour on a dead cold engine. Other than checking for loose intake and timing cover bolts, I haven't done any more research. I tried thumping on the intake and timing cover with a nylon mallet while looking for a pressure drop and saw nothing. Wondering if it's leaking out of timing cover into the timing chain area, leaking under the intake, or a head gasket. I'm going to try pressurizing and hand rolling the engine over to see if I get anything out of the spark plug holes next.
 
I just noticed a heater hose leaking at the heater core connection when pressurized. I tightened the clamp, no more leak and it's now holding 13 psi on the tester. It has held pressure through the entire time it took me to remove spark plugs, turn over the engine, and run a compression check. I found no coolant in any cylinders. All cylinders are running at 150 psi except #7 which is 135 psi. The needle on the cooling system pressure tester does not move when cranking the engine with spark plugs in place.
 
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The cold engine has held cooling system pressure for the past 36 hours. I guess I'm to assume it only leaks at operating temperature. I have never overheated it, by the way. I'll try warming it up and then checking next.
 
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