Coolant in oil in 1999 4runner 2.7 L 3RZ-FE

[pendragon]

1999 4runner, 2.7 L 3RZ-FE, 230K miles. I have an external transmission cooler installed, so no pink milkshake possible.

I had an overheating incident in my 4Runner a little while ago and the vehicle was immediately shut off as soon as it redlined. The coolant reservoir was dry. I tracked a coolant leak down to a hose going to the EGR valve and I went ahead and replaced the EGR valve, the egr hoses, and the radiator, thermostat, and radiator hoses since they needed to be replaced anyway. Prior to this I think I had a little coolant leak into one of the spark plug cylinders, because I have a little bit of a misfiring problem on startup that goes away after about 10 seconds or so, which makes me think it's coolant in one of the spark plug well that's getting cooked off. I don't think the overheating incident warped my head (or warped it much) but I wanted to mention it. The misfiring on startup seems to be getting a little worse as time goes on.

I sent a oil sample to Blackstone labs and this is what came back:

[: Your suspicions of coolant in the oil have been confirmed with these results. You can see the contaminant in the high potassium and sodium. The head gasket is one likely source of the leak, but it will take a closer investigation to know for sure. The good news is that wear looks pretty good, so coolant doesn't appear to be causing serious wear issues at this point. Aluminum was a little high, coming from parts like pistons or bearings. Keep oil changes short (<3,000 miles) until you can get it checked out. Universal averages show typical wear after ~6,700 miles use.

I guess my question is where should I go from here? What's the best way to approach getting this diagnosed and fixed?

 

[4racer]

I would do a leak down test and see what results you get. If its a small leak it may not cause issues now. Being a 4cyl the head isnt that bad to do.

 

[diverscale]

test your cooling system for pressure leaks

Powefist 8 pc Radiator Pump Pressure Leak Tester Kit | Princess Auto

if it does not keep the pressure, then proceed in finding the leak source, if it's nowhere to be seen externally, you can then suspect the head gasket.

If it leaks, and you turn on the truck, with coolant reservoir removed, a head gasket failure might blow air into your cooling system, and you could see bubbling up there.

Your source of prestone in your oil might have been only residuals from the incident, and there might or might not still be a leak into the system.

 

[pendragon]

I forgot to add that I sometimes (not always) get white smoke in the exhaust on startup. Also, I am slowly losing coolant to where I have to refill the reservoir about every 3 weeks.

 

[UnderFire]

Sounds like headgasket to me, it's also likely that you'll have some small cracks in the head between the valves and spark plug holes, a common problem on these engines.

 

[pendragon]

Are those cracks you speak of a death sentence for the head?