New motor on the horizon

[PSoffe]

Lately I have been dealing with a low to zero oil pressure at idle and a slow loss of coolant in my 01. She has a 174K on her and the funny thing is that she runs great, idles as she should has power, no knocks, no ticks.

I thought it was a sender so i put a mechanical gauge on it and it was reading the same. I made the decision to stop going to the local "quicky lube" (generic name) and decided pulled the pan and have a look see. It was remarkably clean as was the rest of the motor and NO sign of any coolant in the bottom end or up top. It is my understanding that the 0331 head will crack between 3 & 4 which is directly below the oil filler cap. NO evidence of coolant there either. I did not pull any rod or main bearings but cleaned the pick up screen and tube, installed a new gasket and Mobile One high mileage synthetic.

Ran much smoother, oil pressure was not great still about 10psi at idle but wasn't falling off to zero. Funny thing is the oil pressure has pretty much been like that since i bought it 3-4 years ago and always holding at 10-12 psi. We've been on several Jeep trips TDS a couple times and multiple trip to the local mountain trails in Big Bear California and never an issue. But now after a couple of weeks, the pressure is falling off to zero at idle again.

That should pretty much cover the back story. As i don't believe a high volume oil pump is going to make things better, i am looking at an ATK motor, i've used them in the past and have not had any issue (knock on wood). they are priced right and should be able to do the job for just under 2500.

So, the real question here is... i have noticed that the ATK motor still uses a 0331 head? I've tried to call them directly with no luck thus far.

Are they doing something different, is it an improved casting or is this the same head that's on the Jeep now.

I'd really like to stay away from piecing a motor together as i need the warranty should something go wrong.

Any help/info would be greatly appreciated!

 

[RCP Phx]

That is a question that only the vendor can tell you! As a former engine remanufacturer I can tell you that you would be surprised at what can be repaired. Cranks that look so bad to most we would weld and regrind to factory specs(even add stroke). Broken block pieces(even missing) could be repaired, cracked heads welded and repaired!

A core motor just gets torn down and the parts are sorted into groups by it application, so in this case it's the casting #. Other than that we didn't care!

Parts that we didn't feel worthy of our time were still sent out to other sources for further rebuilding.
After that if we needed to outsource these parts, you never knew where it came from or what work had been performed on it!

On page #53 of ATK's catalog, they don't list a "new design" head.
http://atkvege.com/content/images/catalogs/head2016.pdf

 

[old_man]

Before you go crazy and start spending money, what oil filter are you using. If it is Fram, throw it away and get a good one such as a Wix. A search on here will yield lots of good info. Fram may be a good filter on some vehicles, but they have a real crappy record on the 4.0L.

As far as a slow loss of coolant, an old radiator cap can cause this and you will never see any signs. You should replace the radiator cap at least every two years.

I'm not saying you don't have a cracked head but why not check first.

The last thing is to pull the plugs and put pix up here. Antifreeze into the combustion chamber (cracked head or head gasket) can cause deposit build up on the plugs.

 

[Ecomike]

Replace the head before it is too late, then install a high flow oil pump and increase the oil viscosity. I use 20W50 on mine, 289,000 miles, 1987 beast. Coolant in the oil drops the oil pressure.

 

[PSoffe]

Before you go crazy and start spending money, what oil filter are you using. If it is Fram, throw it away and get a good one such as a Wix. A search on here will yield lots of good info. Fram may be a good filter on some vehicles, but they have a real crappy record on the 4.0L.

As far as a slow loss of coolant, an old radiator cap can cause this and you will never see any signs. You should replace the radiator cap at least every two years.

I'm not saying you don't have a cracked head but why not check first.

The last thing is to pull the plugs and put pix up here. Antifreeze into the combustion chamber (cracked head or head gasket) can cause deposit build up on the plugs.

Yeah, I guess I left that out its the Napa Gold that as I understand is a Wix filter. I'll toss on a Rad cap this weekend and try to get some pics up on the plugs.

Thanks