I have a 2001 jeep as most members know the 0331 heads are junk, mine cracked and I spent the extra money to replace it with an 0331 Tupy head, long story short the swap went very well, but a week after I noticed the freeze plug on the back of the head had a slight leak, being I just spent all the money on it I pulled the head to replace the freeze plug as well as putting another new head gasket and new head bolts. Being that I was upset and rushing to this I forgot to drain the coolant before pulling the head, so needless to say I made a mess and got coolant in the oil, has anyone had this happen and how offent did you heat and flush untill you felt good about the flush?

 

I would just change the oil and call it good. Everyone who had head leaks got coolant in our oil and 99% didn't fry the rings or bearings. If you're really that worried about it, get some cheap oil and dump a quart or two where you spilled the coolant while the drain plug is open. Many of us have drained entire overflow reservoirs into the oil before we noticed, so don't worry, you'll be fine.

 

Was the engine already trashed before you replaced just the cylinder head?

 

No it was not trashed at all

 

Fortunate, most peeps don't lift the hood until it's too late, a new cylinder head won't fix the cam bearings.

 

I personally know mine was leaking for about two months. I'm fairly confident that it fully cracked and opened when my 6 week old CSF radiator decided it wanted to do a coolant flush on the way home from work one time in August. When I changed the oil at Thanksgiving time, the filler cap was covered in goo. Luckily, the XJ shares DD duty with my Z28 in the warmer months, so it didn't see too much use before I found it. I admittedly should have been more on top of checking coolant levels since I pretty much knew it was going to crack soon, but driving it less means I don't check things as often. It still seems to be running fine, but I'm definitely a little worried about bearing damage.

 

1. if oil pressure is ok at idle bearings are good
2. If you were using silicate free antifreeze damage would be less
3. Most damage is done to cam bearing b/c undiluted coolant from crack pours directly onto cam
4. Other than a drop in oil pressure a worn cam bearing is not a big deal as far as engine survivability goes.

 

A drop in oil pressure most certainly will affect engine survivabilty and longevity.

 

Yup, like I said, everything has checked out fine so far. I honestly couldn't tell you if my coolant has silicates in it because this is the first I've heard of that. Seems pretty dumb though to put any liquid with silicates into an engine, whether it's designed as a lubricant or not.

 

Change the oil several times at very short intervals. Such as the first time it reaching operating temperature idling in your garage/driveway, and then repeat 2-3 times at 100 mile intervals. Its not a bad idea to change the oil after 100 miles after even a normal head job. There is always some grit and coolant that gets into the oil when the head comes off.

 

I was referring to low pressure at idle. As long as oil is flowing to all bearings life is good. A worn bearing causes less restriction in oil delivery....flow is still there.
Pressure is just a benchmark to measure wear.....the only fix is to replace worn parts.

 

I wasn't gonna touch this one, but I agree. Low pressure means gaps, gaps cause play, play causes wear, and wear causes more play. It's a vicious cycle that the 4.0 is actually pretty good at managing until we damage something.

 

that is what I said.....the only fix is to replace worn parts

 

But you also said it's not a big deal. A worn bearing causes everything to wear even faster. If you have low oil pressure due to a bad bearing, it will get worse and wreak havoc.

 

Dexcool, for one, is silicate free.

I got flamed on this Forum in the past for suggesting people with an original 0331 non-TUPY head switch over to Dexcool to avoid probable bearing damage when the head lets go.

You've got to thoroughly flush your system several times if changing over from green coolant to Dexcool. If you don't you'll end up with "snot" in your system because of a reaction between the two coolants.