This is after a 40 mile drive. I planned on putting a new head on. How long is it safe to drive this way. My understanding is this means the head gasket is leaking or has a crack. I was also told that it could be a cracked head.

 

If you've got that much milkshake after only 40 miles, you definitely have a problem. Pressure test to locate the leaks. Look at the spark plugs. Are you using up (burning) coolant? And if so, how fast? What does the dipstick look like? Is the rig overheating?

You should avoid driving until you sort out what this problem is and have it repaired. Otherwise you risk doing more/severe damage to the engine.

 

I've never had it overheat or run hot for that matter. Up tell recently I haven't kept track of any coolant loss but I do know it uses some.

 

The water in the oil will significantly reduce its, well, oiliness. So your all the stuff in the engine that is supposed to cruising smoothly on a thin film of oil will be scraping by on water.

There is no way to tell "how long" you can drive it; for all I know your bearing journals are already scarred. Or not (you do have SOME oil). But driving at all is not going in the right direction.

From my (limited) experience, you are less likely to have a cracked block than just about anything else.

So suck it up, pull the head and have a machine shop pressure test it, visually inspect the block (inside the bores mostly) for anything obvious, and button it back up.

 

A cooling system pressure test would be my first step - to try to establish where the leak (if there is one) is coming or going.

Is the milkshake on the dip stick too? If not consider the possibility of what is in the cap could be just condensation.

 

Coolant system pressure test is a good step. It will tell you if your system is holding pressure, but you might not be able to see the leak. When I pressure tested mine, I found the heater control valve leaking, but other tests also indicated the head gasket was leaking too. And if the coolant is leaking into a cylinder, you will not be able to see it. I guess my point is, you will have to eliminate any visible leaks before drawing any conclusions on internal problems.

As others recommended, check the the dipstick for the oil color. Or change oil or just the filter to check the oil.

If you have an oil cooler, that could be a source of coolant leaking into the oil, so considering eliminating that possibility or do other checks such as cylinder pressure check or combustion gas test to confirm a head gasket issue before pulling the heads. When properly performed (and it is not hard) using a block test kit to check for combustion gases in the radiator is very effective and inexpensive (like $8.00 and 15 minutes of your time).

 

Lots of good replies. And mention of internal damage is on point.

Used To be rule of thumb that once you had coolant in oil that engine would develop knocks in near future. Be it reduced lube factor of oil or chemical reaction between oil and coolant. So choice is mange now or fix problem and test rule of thumb.

 

I'm planning on buying a new head. I might just go to a upullit and get a nice short block. Then put the new head on. I guess we'll see. I don't really have the time to get to far into this truck at the moment. I'm working 60 hours a week most every week. I also don't have another vehicle so this truck is my daily driver.

 

pressure test old head and throw a new head gasket on. Buy some time and get yourself in a better situation to do the job right.

 

Ever seen a mill running, the white stuff they are spraying is an oil water mixture to keep the bits cool, oil water mix is only good as a coolant when cutting metal not as a lubricant.

Subtext don't drive it and don't run the engine any more than is needed to pull it under your hoist or into the garage and even then push it if you're able. Every revolution you're gambling with replacing the crankshaft and other rotating parts.. water is only "incompressible" when fully contained it has zero resistance to compression otherwise aka zero viscosity it's what the viscosity scale is based upon.

You'll need to pull the pan and inspect bearings, also the head to inspect the cylinder wall, you can eyeball the timing cover but it's easier to just pull the engine and it's wiring harness and do all the above outside the engine bay. Don't forget to check for block and head warpage.

 

How long do you think that would last and do you think the bottom end would be ok??