Waynerd

So I just swapped the water pump on one of my 98 Cherokee's yesterday. The water pump was rattling around like crazy until it finally started to leak. The Jeep isn't currently driven but I was always starting it as often as I could and letting it idle and sometimes take it for a short drive.

When I removed the pump I noticed a spot on the cylinder in the hole for the pump. There was a little slimy stuff on it. In that spot I could see where the impeller had been contacting the cylinder. I didn't get it fired up last night because it was late and only 26 degrees.

Today on my lunch break I stopped home and wanted to fire it up so I could tighten the belt if I needed to before I reinstalled the shroud and electric fan. Figured I would check the oil before I started it. To my surprise the level was significantly over the full mark and the oil looked as though it may have mixed with water.

Question is whether anyone has heard of or had the cylinder crack behind the pump? It was sitting for like a month or so. Not sure what else could have happened. All the times I ran it with the bad pump it didn't overheat as far as I could tell. No gauge though, just a light.

Waynerd

I took a couple pictures but after I wiped it off. If you look in the coolant there is some light colored stuff. That's some of the slime that had ran down. Notice the casting texture is worn off but I wouldn't think it could crack through the block or the block and sleeve.

Waynerd

Here's one where I tried to get up higher where I couldn't see. A little blurry.

BlueRidgeMark

That's a new one. But, water in the oil is already bad news. It doesn't take long to wipe out your bearings.

tech

It looks like the water pump was hitting the cylinder , it should be ok because there would be oil in the coolant if it was cracked .

cruiser54

Either way waynerd, this is a good poster child moment for taking care of things like this in a timely manner.......

Waynerd

Here's a pic of the oil and level. That was after sitting overnight. I ran it to temp after but I didn't get a chance to check it again. I'll check it today and see if the level went up. If so I guess I'll be pulling the head. Just sucks because I was planning to put this on the road while I did major repair to my other 98 and let my wife use it while her '01 was down for repair. It only has 163k on it too. On the up side at least I can fix the exhaust manifold gasket leak too.

Waynerd

This pic is for reference as to how far past the full mark it would be since the mark wasn't really visible when the oil was on it.

BlueRidgeMark

That ain't good.

CoffeeCommando

A starting compression test will tell you very fast if one of your cylinders is leaking anywhere.

The cylinder doesn't have to crack for that issue to have caused some other problems elsewhere. You have metal in your coolant system now, so at a minimum you need a flush.

I had a machinist recommend against me boring my stroker over to .060 because the #1 cylinder was the thinnest and he didn't like how thin it was at .030 over. I recommend you only use pure distilled water with every coolant fill up. I make hydrogen fuel cells and can attest to the electrical capability of tap water over distilled. It's a beyond night and day difference. Distilled water is an electrical insulator, not conductor; and the electrolysis process is what causes rust formation (from eating up metal) in the coolant system. Since you have a thinner spot that looks more capable of rusting than anything else.... I wouldn't gamble on anything other than distilled water, lest you find a hole in your cylinder 5 years later.

Waynerd

Thanks for that info ^. I actually used distilled water when I refilled for the first time in my life. At 89 cents a bottle it's worth it. And easier than having to fill bottles first. And most of my coolant had leaked out already as it sat for a month. But I still plan to do a flush. Did so on my other 98 and will do on the 01 soon.

So to update, I ran the Jeep a few times. The thought process on that was maybe some moisture had built up during its resting period. If I ran it to temp a few times the moisture may burn off. Checked the oil this morning and it was at the same level and maybe looked clearer. Of coarse I have photos. Also no other signs.

Waynerd

1

Waynerd

Yes the oil is a little dark. Going to do a filter and oil change today. Also I seem to recall over filling the oil slightly last fall when I was topping it off. I'm pretty comfortable with just doing the oil change for now and keeping a close eye on things. Went through with a fine tooth comb on inspecting for any other signs of a bad gasket or oil and coolant mixing and found none. Of coarse I know it doesn't at all rule it out like actual testing would but I don't think it's required until I start from scratch with the oil and go from there. Also the motor is purring like a kitten at the moment.

s346k

if the oil has water in it the 2 will separate over night. loosen the drain plug the next day and see what comes out. if the cyl was cracked there i imagine it would charge the cooling system with air. i think you’re fine, that oil simply looks overfull.

Waynerd

That's what I'm hoping. The oil just looked a little too cloudy when I first checked it.