Coolant in oil on new rebuild - SOLVED

I must have missed something fairly simple... 1970 455 block machined, new TA Stage 1 SE heads, original intake. I used a splash tray and standard intake to head gaskets (not the pan type like it originally had.)

Anyway, just started filling all the fluids for first startup, and coolant started seeping out around the oil drain bolt. Already had oil in, but the engine hasn't been run yet. The fluid in the radiator stabilized and only dropped about 1/3 of the way down from filled. I don't recall that any of the bolts go through the water jacket on the standard heads, so I didn't seal any. Maybe a clearance issue with the intake?

I'll start getting in to it in a few days, but wanted suggestions on where you might suggest I start. I've never run into this on a rebuild, but at least it's a relatively harmless screw-up The engine wasn't run like that, so I just need to find my leak and replace some oil.

 

Where did you fill it from? The radiator cap?

A worse case would be if the timing cover was leaking coolant into the oil down the front of the block.

 

Not sure on the stage 1 heads but the stage 2 heads have a core plug under the valve covers that need plugged...

 

I did. I had the temp sending unit out of the intake to help fill the block since the thermostat doesn't have a bypass hole in it.

 

There IS a threaded hole there with a plug in it. That was one of the first places I was going to check since I didn't remove the plug or seal it in.

 

You didn't use early head gaskets on a late block did you? All replacement gaskets work for 67/76 blocks so unless you used original steel shim that shouldn't be an issue,.
Did you dry fit the intake to check the flange angle? Would only be an issue if the block was decked alot

Timing cover isn't sealed thats your 3 options,..other than the deck plugs in heads

 

Time to drain the oil and yank off the Intake and valley pan sheild ,then see if the coolant level that you say stopped 1/3 the way down from being full matches the mating height of the heads Intake flange, if it's below that then it must be a timing cover leak it would seem to me.

 

So far I've verified that it's not the timing cover or anything under the value covers, including the threaded plugs that come on the Stage 1 SE heads. I'm going to try to use a level to see exactly where the radiator coolant level matches up with the engine, but I'll be pulling the intake and checking that this weekend.

 

I used the Orange Crush gaskets from TA, so I expect they should (hopefully) be the right ones. I will be impressed with myself if I somehow put them on wrong, but I'll sure double check that. I'm thinking it could be the stock intake not sealing properly with the head(s)

 

Was the oil sending unit drilled for some reason by the machine shop or you?Ask me why I know.Bruno.

 

No drilling there The one that was in the engine had a brass reducer, but the new one I got fits the hole correctly.

 

How long was the brass reducer and was there any traces of sealing compound on it?Bruno.

 

Ok, so it was the intake manifold gasket / rail seal. Once I pulled the intake off this morning (after checking the bolt hole depth to make sure the bolts weren't bottoming out; they are aftermarket heads), it was obvious that the rear part of the manifold wasn't sealing. There was extra gasket material (the intake gaskets I used stuck out too far) and it combined with the corners of that rubber strip seal to not allow it to close all the way back there. I'm going to get new intake gaskets, make sure I trim away any excess material that may overlap those ends, and use some Ultra Gray on the front and back rails instead of those rubber strips.

How diligent do I need to be in removing traces of coolant in the lifters? I vacuumed them in place but I didn't remove them. Will those small amounts of coolant be an issue during startup? I'll be changing the oil immediately after that.

 

If you place absorbent paper towels around the lifters and drainback holes, then WD-40 will displace the water.
Dab them dry and then a few squirts of oil on each lifter, and you should be good to go. Since you did not rotate the engien with the water present, you should be fine.

Some may say press on and not worry about the moisture, but I'm OCD about stuff, and since it's accessible, I'd be poking around in engine innards.

 

If you just change the oil a few times every 5 mins of running. After a few changes all should be good

 

I’d pour a quart of break-in oil down the length of the cam tunnel before changing the oil prior to your initial start. If you used a quality cam break-in lube, no worries about washing it off.

 

You've got...what? Two ounces of coolant on the lifters? You've drained the pan. There's going to be 5 or more quarts of oil.

I'd mop-up whatever was easy, and then not waste ten seconds thinking about multiple oil changes to remove an ounce or two of coolant, half of which will be water which gets removed by the PCV system when the engine warms-up.

Engines run for months with seeping gaskets bleeding coolant into the engine. Eventually they may overheat when the coolant level gets low enough, but they don't tend to have lubrication failures from a little bit of coolant in the oil.

 

As the intake is already off, it isn't like there's a bunch of extra work to mop up the remaining coolant. As Larry said, pulling the lifters, disassembling and cleaning them up, is at this point, no big deal. Sure, boat guys deal with an ounce or two of coolant all the time but why take the chance on a brand new engine?