stephanie42

I have read SO MANY posts on here about the 0331 head and I still have questions. We have a 2000 Grand Cherokee 4.0 inline 6 (my partner and I). CEL on, codes for multiple misfire and misfires on 5 and 6. The CEL started flashing and lost power on the way home, so we had it towed. We saw some coolant in the oil and oil on plug 6 so we started down this road. Compression test showed 170-180 on all cylinders except 3, which was 80. We've pulled most of the stuff out, next up are manifolds and then valve cover. I am planning on buying a new head from Clearwater because why the heck not. I don't want to have to get back in there again any time soon. Also a new thermostat/thermostat housing because it looks nasty af, and a handful of hoses. I'm all about replacing stuff now while it's all apart. I have the Haynes manual and neither of us are novices.

Here are my questions:
-What else should I check while this is all apart? What am I looking for?
-Should I get a head with valves or without? How annoying are the valves to replace?
-Do I actually clean the engine? How and when?

Thanks

97grand4.0

Before spending $$$$ be sure you know what you're trying to fix. After reading your post, I am not sure. So, you have low compression, if you did the test right, on cyl 3, and based on that alone you're going to go ahead and assume you have a cracked head. Hmm. S0 low compression on 1 cyl means a bad head gasket, is that what you're asking? Typically a gasket would mean 2 cyls low. One could mean piston rings, valves, cam lobe, or yes the famous cracked head for which there are many threads here.
If you do pull the head, dont replace it. Bring it to a COMPETENT machine shop, one that says something like XXX Racing Engines. Not some hack that will tell you absolutely nothing about what they find.
You will also want to do lifters, you will measure your present head gasket and replace with one of similar thickness, OR, you will set the lifter preload to .020-.060.

PS there are NO 'NEW' heads. They are ALL rebuilds. Likely worse than what you have now.

dave1123

About the "new" heads, I beg to differ. When I bought my "Clearwater" head, it was a new casting. Odessa Cylinder Heads in Clearwater FL does sell reman heads, but they also sell brand new castings. IBT they don't sell direct anymore but use second party distributors, but you should call them to find out. Mine cost me $455 complete with new valves, springs, and seals, free shipping BOTH ways (core return), and warrantied for 60 months against cracking unless severely overheated. There's a melt tag on the back of the head to show this. The new casting you just bolt on and go, not preload necessary. I got mine in 3 days because they have a warehouse here in southern NY.

third coast

Coolant in the oil is a pretty good sign that there is a cracked head given it is a 0331 head. Even if it was just a head gasket I would replace that head, especially if it overheated at all.

I encountered a cracked 0331 head on my 2000 Cherokee and went with a rebuilt “TUPY” casting head. I considered a new Clearwater head but at the time they had a number of bad customer service reports and it seemed that the heads were manufactured in China. I can’t say that one way is much better than the other.

My thoughts:
* An oil sample sent for analysis will help show what is going on. The analysis will confirm if coolant is present and if wear metals are exceptionally high. If the wear metals are significantly beyond the norm this is an indication that there is likely significant damage beyond just a head issue. You may then want to reevaluate the direction to take.
* I am not clear on your question on cleaning the engine. Before you remove anything else clean the external thoroughly, especially where the head attaches to the block. Cleanliness is important to a good outcome. Do everything you can to prevent dirt, carbonized oil residue, head gasket particles and miscellaneous parts from getting into the engine. I have commented on this elsewhere on this forum but ask if you can’t find it.
* Remove the head with the manifolds attached. It is heavier but much easier for removal and installation as you do not have to struggle with hard to reach bolts. On installation some of the bolts are nearly impossible to torque properly if you try to mate the manifolds to an installed head
* If the head is being replaced definitely get a head with valves.
* If you do not have a torque wrench buy one. Head and manifold bolts especially must be torqued to specification to help ensure a good outcome.
* Inspect the lifters. (No preset or adjustment possible) If the engine is clean inside with the head off the lifters should come out using a strong magnetic pick up tool, or there are special tools available. Mine came out easily. Pull them one at a time and check the bottom that rides on the cam. They should be smooth and slightly convex. A problem with antifreeze in the oil is that it forms hard particles that can wear cams if enough antifreeze has been present for much time. Severely worn lifters likely means a worn cam, a much bigger job and a sign that other wear has likely occurred.
* If the water pump has not been replaced I would do that while you have the head out of the way.
* I recommend replacing the head bolts and the two manifold studs, one at each end of the head. Studs are available from Chrysler and other sources but for something like that I like using OE parts.

97grand4.0

About no valve lash required, I beg to differ. For one thing if your head gasket is a different thickness, you will need to shim. To set up a new head with the non adjustable valves without taking the time to check, is asking for it.
Well, ok, new casting. Maybe. At least they claim it is. But either way it did not come from Mopar, so, it may be new steel but technically I make the case it is not a new head. It's an aftermarket head.

dave1123

Whatever....100K miles on that head says it was good enough. Then the engine was pulled because the rings had given up.

97grand4.0

Keep your papers out of my driveway.

stephanie42

I appreciate all the tips! We went with head gasket/possibly the head because of the antifreeze in the oil. We're already in this Jeep for more money than I care to admit and made the decision that we'd rather spend the money fixing the engine than buying another car. My partner has been able to borrow a family member's car long-term, so we have a few weeks to do what we need to do.

As far as cleaning the engine, I haven't pulled the manifold or head yet. My partner got excited when we made the decision and started pulling stuff off the engine while I was at work. I'll make sure we take the time to carefully clean before we move any further.

New lifters were on my list, as was thermostat and housing, a bunch of hoses, and CCV. Water pump was done a few months ago. Have a torque wrench (the only thing I didn't already have was the little tool to get the blasted fuel line off). I bought new head bolts but not manifold studs (adding to my list). I hadn't thought of an oil analysis. On Blackston's site it has a standard analysis and then a bunch of other stuff - is the standard enough? If anyone has used Blackstone, what's the turnaround time like?

97grand4.0

Have you rented a free radiator pressure tester and seen if you have a leak? I just did this job myself twice,( not because of a leak or head, mine is a 97) in the last year, . You might only do it once, if you pay attention to setting the lifter preload before turning over the engine. And again, use the .040 gasket. If set up right you may avoid lifters damaging the cam and exploding and gushing oil 8 mos down the road, thus starving the other lifters. This is a non adjustable valve train. Which means you have to set it up right and there is only a .040 range. It's just mandatory, you have to do it. The manual says nothing about it, either, but google a few terms like ' lifter preload" or "setting valve lash with non adjustable valves"/ The temptation is just throw the new parts in and go. Don't do it. Lifters are very close tolerance in this engine. The plungers need to ride at a certain height. New head, milled head, different head gasket, valves a different height, new rocker pivots or rockers, and all that changes. It's really not that hard to do once you understand it. Otherwise you might find yourself with some banged up valve components and no oil on your rocker arms, Sounds like you are being careful about it, you should be ok.
The real cleaning is INside the engine.

97grand4.0

If you're strong there is no need to pull the manifolds you can lift the head out, and put it back in, with them on. Which is a huge time saver.

stephanie42

We did not test the radiator pressure, and too far gone to do so now! I'm having some trouble finding what I need re: lifters in the Haynes manual, but it's early and I've only had two cups of coffee so I might have to look later. I knew the lifters are one of those finicky parts that have to be addressed meticulously. I'm considering ordering them just in case so we have them if we need them - I can always return them.

We're strong, but I'm not sure if we're THAT strong! I definitely want to try pulling it all out together. Sounds like a timesaver. We have a bench we can put the whole thing on and inspect or do whatever we have to do.

97grand4.0

Ok. Well you absolutely should replace them they don't cost much. Throw the Haynes manual away! I can send you a link for the 98 factory manual. I could walk you through this whole thing. Also you will need a lil bottle of Assembly lube to coat stuff with, like the bottom of the lifters, rockers, etc. When you fire it up for the first time (after you set your preload) do NOT run faster than an idle until you get oil to all the rockers and the lifters stop ticking.

third coast

Blackstone Labs is the place I use for oil analysis. It typically takes them 4 business days to get you a personalized report once they get the sample. Order a free sample bottle now or you can use something equivalent. It you have questions give them a call. They are very helpful. Getting the sample to Blackstone can take a long time as USPS sometimes delayes the prepaid sample container. It is faster if you put it in a box or envelope and send first class. Try to take the sample mid way through an oil drain.

I would not recommend buying lifters now. They hopefully will be OK and If they are significantly worn the cam really should be replaced. A big job.

I will provide some tips on getting the head out later.

third coast

And regarding the oil analysis, you just need the standard analysis for about $28.

97grand4.0

My tip is to get he factory service manual which has the torque sequence, pattern, etc. number of passes, etc. what type sealer to use on #11 bolt etc