Water in my oil

[gumper]

I’ve been chasing a water leak into my oil. I’m changing intake gaskets for a second time, and going with thicker SCE gaskets instead of Fel Pro 1213s (also used RTV around the ports and in place of the cork end gaskets). The heads have been milled .010 and the intake was milled to match. The angle looks fine, so I’m hoping some thicker gaskets solve the problem.
But what if it doesn’t?
This engine was built beginning of 2024. I did a leak down test of each cylinder, and they were all nearly 100%. That would seem to rule out a head gasket. I used a pressure tester on the radiator, and it hardly lost any pressure overnight. I know it’s water from the cooling system and not condensation because the radiator level has been dropping.
I even checked to make sure the bolt where the power steering used to be didn’t go through the #1 cylinder, and it’s fine. I was also going to pull the water pump bolts and put sealer on the threads which I’ve never had a problem with before.
Where else can I look?

 

[Oldmanmopar]

Water in the oil?

Did you check to make sure you didn't put to long of a bolt on the timing cover, Drivers side second one up from the pan. If you had a power steering bracket and removed it. Then used the same bolt in that hole usually you crack the cylinder. That is how close the cylinder wall is on a 340. Always check the depth with a small rod and compare it to the bolt. You won't even feel that you bottom it out when you tighten it before you crack the wall.

See it all the time. Put many sleeves in for that reason. Its the price you pay for doing your own work without checking the depth of every hole. I hope its not your problem but like I said we see it all the time especially 340

Hole in #1 cylinder wall near bottom

 

[gumper]

Water in the oil?

Did you check to make sure you didn't put to long of a bolt on the timing cover, Drivers side second one up from the pan. If you had a power steering bracket and removed it. Then used the same bolt in that hole usually you crack the cylinder. That is how close the cylinder wall is on a 340. Always check the depth with a small rod and compare it to the bolt. You won't even feel that you bottom it out when you tighten it before you crack the wall.

See it all the time. Put many sleeves in for that reason. Its the price you pay for doing your own work without checking the depth of every hole. I hope its not your problem but like I said we see it all the time especially 340

Hole in #1 cylinder wall near bottom

Yes I checked that. I did mention it in my original post. I have a belt driven fuel pump, and the bracket mounting bolt runs through that hole. It isn’t long enough to hit the cylinder.

 

[Syleng1]

Internal crack in the block - or coolant leaking around head bolts. Stranger things can happen. A leak down only rules out cylinder leakage not oil or water passages.

 

[matthon]

My 318 poly, same timing cover as a 340 iirc, started to leak a tiny spray of antifreeze between it and the block.
If it wasn't on the outside I wouldn't have noticed it until the oil became a milky mess.

 

[66Valiant528]

In the second picture the top of the intake looks closer to the head than the bottom does. Could be an illusion. The gap doesn't look significant but it could be an indication that the intake cut isn't at the same angle as the head face.

 

[dano]

Aluminum heads? If so what head gasket?

When you added sealant around the ports did you do both sides of the gasket? What sealant did you use?

 

[gumper]

Aluminum heads? If so what head gasket?

When you added sealant around the ports did you do both sides of the gasket? What sealant did you use?

Aluminum heads, Fel Pro 1213. Used Permatex Optimum grey and let it set for a day before filling with water. RTV on both sides.

 

[gumper]

In the second picture the top of the intake looks closer to the head than the bottom does. Could be an illusion. The gap doesn't look significant but it could be an indication that the intake cut isn't at the same angle as the head face.

Just the angle of the picture, it’s flat like the other side. I couldn’t get a feeler gauge of any significant size under it.

 

[dano]

Aluminum heads, Fel Pro 1213. Used Permatex Optimum grey and let it set for a day before filling with water. RTV on both sides.

Are you getting the intake bolts torqued adequately? As I recall I had to go around mine 3-4 times before they all settled. I have SpeedMaster heads and 1213 as well.

 

[Oldmanmopar]

Was the block and heads pressure tested? I didn't see that question asked. The place they crack is at the bottom of the cylinders. If it still leaks I would pull the pan down and look to see where it is coming from or you'll chase it forever.

 

[middleagecrisis]

"I used a pressure tester on the radiator, and it hardly lost any pressure overnight." As the block heats up, dimensions change. The pressure test was done cold, correct? I have a temp sending unit that only leaks coolant when hot, so you could have a leak that only materializes when hot. When you pull the intake to do the head gaskets look very closely around the intake manifold water port to see if you have any evidence of leakage. My guess is it's either the intake or head gaskets. Have you done a compression check on the cylinders? An offending cylinder will be obvious. Just spit balling for you.

 

[gumper]

Are you getting the intake bolts torqued adequately? As I recall I had to go around mine 3-4 times before they all settled. I have SpeedMaster heads and 1213 as well.

I torqued them and rechecked them once more before the RTV dried. Seemed to be OK at that time.

 

[gumper]

"I used a pressure tester on the radiator, and it hardly lost any pressure overnight." As the block heats up, dimensions change. The pressure test was done cold, correct? I have a temp sending unit that only leaks coolant when hot, so you could have a leak that only materializes when hot. When you pull the intake to do the head gaskets look very closely around the intake manifold water port to see if you have any evidence of leakage. My guess is it's either the intake or head gaskets. Have you done a compression check on the cylinders? An offending cylinder will be obvious. Just spit balling for you.

I didn’t do a compression test, just a leak down test when it was warm.
The first time I pulled the intake it seemed pretty obvious the gaskets were leaking judging by the corrosion that was migrating through the gasket surfaces.

 

[Desoto291hemi]

W suspect the intake was not milled correctly

Tommy

 

[jeff alder]

If this same engine was run by you b4 the milling and rebuild in 2024 with no problem...I would have to lay my bet on the milling and gaskets.

 

[gumper]

If this same engine was run by you b4 the milling and rebuild in 2024 with no problem...I would have to lay my bet on the milling and gaskets.

Same engine. All I did was go .040 over, more compression, bigger cam and standard overhaul parts.

 

[jeff alder]

Same engine. All I did was go .040 over, more compression, bigger cam and standard overhaul parts.

I had a 318 that had milled 360 J heads on it and an aluminum intake. I dont remember which intake this was so long ago. It was one of my first builds and I had white milk in my crank case. The intake was milled to match the Heads...not by me as I was not equipped. I broke the front ear off the intake trying to get it to stop. I was sick that I had done this and had no extra money. A local machine shop. Ailey's Welding in Crescent City Heli arced the intake...did some measuring and milled the intake to different specs and it stopped. I feel your frustration.

 

[Oldmanmopar]

Same engine. All I did was go .040 over, more compression, bigger cam and standard overhaul parts.

Was It pressure tested after the over bore? My son has an engine machine shop and does several blocks a day. There are some blocks that have porosity in the iron. When bored you could have opened up a pin hole. Something every machine shop should do. If you went from standard to .040 . Was the block sonic tested.

I have also seen timing covers leak behind the pump due to corrosion. Something else to check. The pan can be pulled in the car . Just turn the crank to clear the counter weight. Put the intake on fill it with water and Pull the pan or pull your hair out. Disassembled you cannot fill the engine with coolant.

Every intake installed on a SBM the coolant ports get a light coat of RTV. Many say no but we rather be confident then waste money on gaskets or have them come back for exactly this reason. Dot all I's and cross all T's. Should have run it on and engine run stand

 

[gumper]

Was It pressure tested after the over bore? My son has an engine machine shop and does several blocks a day. There are some blocks that have porosity in the iron. When bored you could have opened up a pin hole. Something every machine shop should do. If you went from standard to .040 . Was the block sonic tested.

I have also seen timing covers leak behind the pump due to corrosion. Something else to check. The pan can be pulled in the car . Just turn the crank to clear the counter weight. Put the intake on fill it with water and Pull the pan or pull your hair out. Disassembled you cannot fill the engine with coolant.

Every intake installed on a SBM the coolant ports get a light coat of RTV. Many say no but we rather be confident then waste money on gaskets or have them come back for exactly this reason. Dot all I's and cross all T's. Should have run it on and engine run stand

I can’t tell you for sure what they did as I probably threw the invoice away and definitely can’t remember. I do know the just the machine shop was $6000, and they didn’t assemble anything. He does all the work for my friends Olds race engines, and they’re always solid.

 

[dusterbing the peace]

I have also seen timing covers leak behind the pump due to corrosion. Something else to check. The pan can be pulled in the car .

This was my thought after seeing so many other things ruled out. The mating surface between the timing cover and the block, specifically around the circular water inlets to the block (leaking in to the timing chain area). As mentioned, may only present when hot. Or, if there’s bad corrosion that’s beyond the “fill limit” of gasket sealer. I guess a simple thing would be to double check the torque on all of the bolts, especially the hard to get to one by the factory fuel pump location that ends up behind the water pump inlet. Can you put the radiator pressure gauge on then heat the engine up and see if you’re losing pressure when hot? A more invasive approach would be to just pull the timing cover and put on new gaskets with new goop.

Another thought would be crack in the heads at a valve seat? That one might be evident on the spark plug.

Sorry to hear, hope you find it!

 

[pntastar69]

Just curious, are there any wet sooty carbon deposits inside the rear exhaust?

 

[mopardude62]

I had a cracked cylinder and didn’t know it until I was running 75 down the interstate! I got water in the oil, smoked the main bearings, broke the crank and locked it up tight.

 

[66Valiant528]

Ouch

 

[gumper]

Just curious, are there any wet sooty carbon deposits inside the rear exhaust?

Not a more than usual. I run methanol with top lube and the crankcase vented to the headers. I get some oiling in the exhaust from that.

I doubt my timing cover is corroded. The cover was new about 15 years ago, and it was in good condition when the engine was torn down last.

I removed the water pump bolts, and none of them had sealer on the threads. I put some Teflon paste on and torqued them back down.