Hey, I bought an OTC 7991 cooling system pressure tester here. Set it into the rad, inflated the bladder and whatnot. Should be a good seal there.

It would hold 15psi in the rad ok, I think it might have been bleeding down very slowly.
I then removed the t-stat, and re-RTV'ed the waterneck back on. Now I pressurized the system (and found a slow leak from the heater core, so I tightened up a hose clamp and i'm good). Anyway, it's still leaking down pressure, but very slowly. It takes 10 seconds to bleed down from 15psi to 14psi. Is this a normal result, or do I have a leak?
Reason I ask is that I'm getting coolant into the oil, and I can't figure out why. I've replaced head and intake gaskets, and it's the same thing - fire it up, 10 seconds later i've got chocolate milk oil.
I figured it was from spilling some coolant, since I don't think it takes much to make the oil milky, but since it happened twice (before and after replacing head and intake gaskets), i'm a little leery on that.
I'm thinking cracked head or block now. However, with the speed this bleeds down, I can't hear any hissing at all. None. I'm using a stethoscope and everything.

Any ideas?

 

Have you tried sending an oil sample to wix?

 

What?

 

Wix sells a deal for sampling oil, looks like a little film bottle, you fill it up with your used motor oil and then send it prepaid (in usa) to them. They fill you in as to how much Hydrocarbons, antifreeze, and other trash is in the oil. Here in the usa it runs around $18. I wish i could remember the part number, but its been about 6 months since i was in the parts business. Probably have to call wix to get the part number.

 

That's a leak. You should be able to pump it up and leave it for 20 minutes or so without losing any pressure.

 

Yea, unfortunately knowing how much antifreeze is in my oil, still doesn't fix my leak though

Hmm, i'm not sure if it's the bladder sealing part that's leaking, or something in the engine. Although i'm fairly sure I have a leak in the block ( due to the oil in the coolant ), i'm still no closer to knowing WHERE. *&^(*%^%

 

yeah but itll give you and idea how much, and if gets in while its sitting or running

 

If you think the block is leaking, you might as well pull it and take it apart. If you can't see a crack when you do, you can take it in and get it tanked. It'll be cheaper than magnafluxing and if you're lucky, a crack will show up as a soda line after it comes out of the tank.

 

Well that's a colossal hassle. I'm fairly certain it's not the head or intake gaskets. I'm pretty sure the block deck is flat, as it was decked when I built the engine, and I checked it with a straight edge before I put the heads on this time. But that's all I really know. Cracked block, ie. requiring me to completely pull it and tear it apart, is really not a weekend easy job for me.

Is there anyway I can narrow it down *before* I tear it apart?

 

Bars stop leak time. Lets see how this works.
I'm going to put it in with the t-stat out, let it run as long as I dare, while keeping the dipstick out. If it overflows out the dipstick, it's leaking too fast. But if the oil level stays constant, then it must be working.
Then i'll change out the oil again (geez, i'm single handedly employing a refinery...)

Lets see if this works now...

 

Don't bother with the dipstick thing. If the level gets that high you've got bigger problems from the crank smacking into the oil.

 

That may have solved it. I added stop leak, changed oil and filter (watery oil), added new witches-brew of oil, ran it. Setting lash hot is hard, I have no sense for that. Anyway, the oil seemed to stay clean, so we'll see on that one.
I've still got to add the t-stat again, then i'll see if it holds together.