Recently I've been going through some coolant and I thought I had traced to my throttle body heater. That leak has slowed to almost nothing, but I'm still losing coolant. I also noticed some white smoke in the exhaust at start up. I also had a cylinder #2 misfire the other day under heavy load (punching the gas to get out of the way of a semi). The misfire might be unrelated.

So I rented a coolant system pressure tester from the local parts store. Lost psi pretty quickly over a 20 minute period. No noticeable coolant leaks that I saw. I didn't think to look at the back of the engine at the time. I thought of that after reading numerous HG threads today. And looking now there is definitely something leaking back there on the passenger side. See attached photo - and sorry for the blurriness. Hard to get the right focus in the engine bay. There's no over heating. Ultra gauge shows temps about 190-194 consistently. That's with the 180* thermostat.

From what I've read this sounds like coolant getting into a cylinder. How do check that? Pull the spark plugs and inspect? Other tests I should do?

I'm especially bummed about this because the previous owner had installed a fully rebuilt 4.6 in the rig. It has about 14,000 miles on the rebuild. Head gaskets should last longer than that.

Thanks in advance for any input.

 

I hate to say it. But, you probably have a cracked block behind a cylinder sleeve. Double check the back of your block towards the fire wall. Typical for a hg to leak in this area.

 

Had it in to the shop. There was a sneaky leak on the throttle body heater so I had them do the bypass.
Turns out the smoke I was seeing was just exhaust. It was looking thicker and smoke-like in the weather we've had here lately.
And I think I'm paranoid that the problems are always bigger on this rig.
Happy to know it's not a big ticket item.