Originally Posted by extrashaky

Do this. After I started sending samples off to Blackstone, I doubt I'll ever do another oil change without an oil test. They'll send you the collection kit for free.

Also, another test you can do to confirm or rule out head problems is to use a combustion leak tester to test for exhaust gas in your coolant. You can buy a combustion leak tester for about $50, but you can probably find a local mechanic who has one. It's a quick and easy test.



That ain't right. Is it kind of milky reddish brown? Is your oil level rising between oil changes?

Again, an oil analysis can tell you a lot about what's going on.

I had the 0331 head crack in my 2000 XJ. The symptoms were that it inexplicably ran hot sometimes (but not always), and changing out cooling system components never really solved the problem. The water pump failed, so I replaced it and flushed the system. Within a year after that I noticed brown sludge in my coolant, and the the water pump failed again. You can tell when a water pump fails by looking for coolant leaking from the weep hole directly underneath the pump, which will run down the lower hose. You might think you have a hose leak there, but if you see a leak there, it's probably coming out of the weep hole.

I thought I was having a bad run of luck with water pumps, but now I'm convinced it was the sludge that killed the second one. That sludge was a huge warning sign. It's not rust. It's the particulate matter that is left behind when coolant boils. I ended up replacing pretty much the entire cooling system before it was over, and the truck still intermittently ran hot.

Eventually I started seeing oil pressure problems like what you're describing, although I didn't get the rattle. I never saw the milky film under the oil cap people talk about, but the oil itself became lighter in color, more of a reddish brown. That turned out to be water in the oil.

I was never able to confirm what was the actual proximate cause of the low oil pressure. I did not get the rattle like you describe, but that rattle could be a failed cam bearing allowing the oil to flow past so that you lose pressure. The common cause of cam bearing failure is water in the oil, which is why some of us instantly thought 0331 head when you described your issue.

In my case, I was on a road trip when my oil pressure gave out, so I took it to a great old mechanic I had used when I lived in the town I was visiting. He took one look at my oil and said there was water in it. Then he used the combustion leak tester while I watched and confirmed the presence of exhaust gas in my coolant. He changed the oil and patched me up enough to limp back home.

So what was happening in my case was that there was a crack in the head between the number 3 and number 4 cylinders that would open up sometimes (but not always), spewing exhaust gas into my coolant and boiling it. That explained the intermittent overheating. The boiled coolant left behind that reddish brown sludge that was clogging up the system and killing water pumps. Eventually the crack opened up enough to start dumping enough water into the oil to cause problems there also.

This is why I say that an oil analysis and exhaust gas test will tell you a lot for not a whole lot of money. If I had been getting the oil analyzed all along, I probably would have been able to diagnose the problem a lot sooner and save myself a lot of unnecessary expense. If either test comes back positive, you know you have a head problem. Hopefully it's just a gasket and not the crack.

To be honest, I'm amazed that engine held up as long as it did under those circumstances. Good luck with yours.

Originally Posted by salad

Oil isn't going to bake unless your engine has been hitting 350 degrees.

Originally Posted by mtulett1

no milky looking substance and no increased oil levels, my take is the oil is getting burnt because of the leak i had in the cooling system and the engine was running hot. not sure if thats possible but we shall see i appreciate all the help though

Originally Posted by extrashaky

I seriously doubt that's what is happening. If the oil were getting hot enough to burn it, you would have long since overheated the engine and locked it up.

But then again, I'm not an oil expert. Blackstone is, however, and their test would be able to tell you a lot about what's going on in the engine. It is very easy to grab a sample and send it to them. They send you the test kit for free (just request it on their website), then charge you $25 when you send the sample for testing and email you the results. You do not need to pay the extra $10 for a TBN.

If you do go that route, in your case I would suggest that you put Blackstone's pre-addressed oil sample container in a small box and ship it UPS. For some stupid reason the idiots at the US Postal Service don't understand what you're sending, and they can quarantine it for a month while they wrench and pull on their heads to try to dislodge them from their rectums. If you send it UPS, it'll get there in a few days, and Blackstone will email you the results the next day after they receive it.

Good luck.

Originally Posted by mtulett1

i have 235000 miles on my 01 XJ i put a new oil pump in around 120000 miles. Oil pressure is dropping to zero when I stop at a light and when i'm running its just over 20. Do i need to rebuild my engine or do you think its the oil pump again? i do here some slight rattling type noises. any help would be appreciated.

thanks

Originally Posted by CCKen

I needn't go any further in this epic thread.

Change the engine.

Originally Posted by mtulett1

do you know anyone that could do a good job in our area for a decent price

Originally Posted by CCKen

Do a good job doing what? Rebuilding the engione or just changing the engine?

Originally Posted by mtulett1

Just changing the engine

Originally Posted by CCKen

I changed my own engine so I had no need to find a shop to do it.

You could call Jason at Jay-Fab-Offroad, in Plymouth, and ask him if he knows of a shop that does Jeeps.

http://www.jay-fab-offroad.com/

I know he has a buddy that works in a small shop a few streets over from his shop. Maybe they can do it. Or maybe he can do it.