nmillard

I took the Jeep to Midas. I am not a fan of Midas, but I am not in my home town right now and a friend here recommended them. They put a mechanical pressure gauge on the engine (I tired to buy my own and nobody in this town carried one) and they told me the pressure was fine. They went to put the sensor unit back on, and said it crumbled in their hands. Strange, because it was brand new. They said they replaced the sensor unit with a new one and it reads fine now. I will wait to pick it up tomorrow and drive it around to make sure. I don't trust just any mechanic. I asked if they made sure to drive it around and warm it up. I will check tomorrow. They also told me the AT fluid was dark and needs change and I just changed that yesterday. I have my fingers crossed, but I will pick the Jeep up tomorrow and drive it around to see. They did say that it appears the guy who owned this Jeep before me didn't change anything. It still has the original shocks on it. They also said the coolant looked contaminated...which makes me think it still has a cracked head. I sure appreciate all the help from everyone. I started surfing the web for another XJ, but there sure aren't too many around. My last XJ was in much better shape. I shouldn't have sold it.

Northwoods Snowman

I would still try to get your own gauge. Most auto parts stores carry them or find a Harbor Freight or Sears or something, they usually have them too. I did have two new oil pressure sending units have the plastic housing pop off them (got them from O'Reilly) after a short while, but I would still be suspicious if they don't show you the old unit. You sould ask them to give you the old part and then you can take it back to the autoparts store you got it from if it is bad.

It's possible the unit was bad, but the way the sending units are wired, if they fail the pressure will peg to 80 psi, not 0psi.

Firestorm500

I don't see how Midas stays in business. They rip people off so bad. And charge the hell out of them to do it.

A new unit "crumbled" in their hands?

ATF "dark" and needs changing? Just after being changed?

Good gravy.

Northwoods Snowman

Well, as far as the ATF goes, if the system wasn't actually flushed, it can still look dark, especially if it wasn't changed in ages prior. You don't get the fluid out of the torque converter by just draining it. When I changed my fluid, I disconnected the return line from the cooler and pumped the fluid out of it, and it took probably two gallons to get halfway clean looking fluid out of it.

For the sending unit, that's why I would demand they give me the old parts back.

wildbill1

Maybe the XJ sending units are different, but I just changed the sending unit on my daughters '99 Grand Cherokee because it was going to "0" at idle. A new sending unit fixed it and the guage reads normally now.

Northwoods Snowman

Well, I guess it depends on how it fails, or if it completely fails or not. They will peg out to 80 when the circuit is opened, as in the gauge isn't getting any signal from the sending unit.

nmillard

OK, new plan. Midas wants to charge me for the labor and parts on the sending unit, that was brand new, and crumbled in their hands, and also did not fix the problem. They told me the pressure was fixed, but it wasn't. They said they ran a mechanical gauge for 30 minutes and the pressure held. They replaced the sensor and said they did an "extensive drive test" and it did not fail. I drove it for less than 5 minutes and the pressure crashed to zero. After reading up, I am pretty sure about the cracked head. Too many coincidences for my likings. I am going to try to get them to put the mechanical gauge on while I am there and after I warmed up the Jeep. If it read good pressure, I will pay for the new sensor. Sounds fair right? I have the receipt from a brand new sensor only days before. Regardless, if the pressure holds on a mechanical gauge, then I am in the clear and maybe there is something wrong with the wiring to the gauge. I am betting Midas didn't really warm the engine up to test it. I hope I am wrong.

Regardless, if it really doesn't have pressure, I am thinking about replacing the head. I am not at home, but my friend seems to have most tools I might need. What should I consider when changing the head out on this thing? Should I flush coolant while doing this? IF so, are their any good websites with pictures to help walk through this whole procedure? I have the service manual and the Haynes manual. Should I worry about other things in the engine to replace now? Do I need to do the oil pan and oil pump? Thanks for all the help.

Northwoods Snowman

If the pressure is dropping out, and you're going to change the head, you'll be better off pulling the engine and changing the crank and cam bearings while you're at it. The head may have let the water into the oil, but if it's not holding oil pressure, the lower end bearings are shot. It could be done in the vehicle, but if you have access to an engine hoist and a stand I think it would be a lot easier (and faster) to just get the engine out so you can work on it.

nmillard

I don't mean to be lazy, but I am not at home and I don't think I have the knowledge, means, or tools to do that job. Do you really think it is necessary?

Northwoods Snowman

Afraid so. If you change the head you'll take care of the water getting into the oil, but it's not going to bring the oil pressure back up.

Check your PM's I'm sending you something.

Firestorm500

If the oil pressure really is low, a possible cracked head or blown head gasket doesn't have anything to do with that.

The engine needs to come out and be rebuilt top to bottom. Bearings are gone. You can't just scattershot these things and hope for success.

This is assuming the oil pump & screen are OK.

As much as it pains me to say it, if you can't or won't rebuild the engine or have it rebuilt, sell the Jeep.

nmillard

Ok, I have decided to do the rebuild on the engine. For now, I have to drive the Jeep home. How much damage do you think I could make driving for about 5 hours to get to a place where I can work on it. Also, I know I need to replace the head because that is the crack. The crack created wear on other parts. I wish I had time to pull apart the engine and only repair what needs to be repaired; however I don't know that I have that much time. Anyways, what all should I plan to replace. I see they have rebuild kits out there, any recommendations? What else should I change or fix while I have the engine out?

freegdr

if theres no oil pressure you going to blow it up and then you got the long tow bill better to rent a dolly and u haul pu and pullit home in the long run it will be cheaper you get so many free miles when renting

Firestorm500

It won't make it 5 hours to home.

Either pay to have it towed with a flatbed, rent a truck and trailer and tow it yourself, or sell it where it is. Get what you can out of it.

Engine will have to have a total rebuild top to bottom internally. Assuming it is salvageable and your core is OK.

Cores are available for an extra charge.

nmillard

OK update. Pulled oil pan and the cam shaft bearings all look great. The screws to the oil pump were about 8 pounds pressure. The mechanic I am working with thinks it might be that. Everything else looks good. No irregular wear on the piston, no metallic stuff in bottom of oil pan. He doesn't think the head is cracked either, but he does think it overheated. The water pump was changed out. We are putting it all back together with a new oil pump installed and we will see what happens. The spring on the oil pump looked good though. Who knows for sure.