So I just bought a 2000 cherokee sport in really good shape and it only has 89,000 miles on it. I just started noticing the oil pressure dropping a little and my coolant reservoir getting low even after filled. I'm guessing I have a cracked cylinder head I called a mechanic I know and he said he would take apart and replace if it was for 600 to 800$ my question is, is this a good deal and worth it to fix, little worried cause some friends said I shouldn't have bought to begin with!

 

are you still driving it regularly?
what does the oil look like?
if the oil pressure is dropping a lot, you may have damaged the bearings already

 

Welcome!

Yeah,what Timberwolf said. Might be best to look far a used engine.

 

89K mi and in good condition, definitely worth fixing.


Like others said the low oil-pressure likely indicates bearing damage, likely from a cracked head and coolant contamination of the oil indicated by the unexplained coolant loss. It would probably be a good idea to drop the pan and inspect the bearings before doing anything else to that engine.


A used or reman engine is probably your best bet if the bearings are shoot. A rebuild would usually only make sense if you can do it yourself or find someone you trust who will do it for a good price, at most shops the labor for a rebuild will exceed the cost of a replacement engine.


I would personally recommend using a "TUPY" head from an 02-04 WJ or 02-06 TJ or a new head (from Clearwater cylinder heads, etc.) to avoid the 0331 head issue in the future or using a complete 97-99 engine and either fab'ing up some coil-rail mounts or replacing the coil-rail with a Dodge Viper coil-pack which uses wires and allows you to mount it some place remotely.

 

Yeah as soon as I seen the oil gauge dropping and coolant disappearing I called and took it to mechanic. Oil doesn't look bad and under oil cap was only a little milky I got a oil change as soon as I bought it. I don't think bearings are bad, I hope. The guy I bought it from only bought from his buddy to drive for the winter all he did was new radiator and new tires . It's a awesome looking jeep I would post a pic but don't know how

 

When does the oil pressure drop and how low does it go?


It is normal for the oil pressure to drop as the engine warms up and the oil thins out but severely low oil pressure usually indicates worn bearings. Factory spec is 13 psi min at hot idle and 37-75 PSI above 1600 rpm (at least 10 psi per 1k rpm is also a good general rule though not the official spec.). It is also good to measure this with a mechanical gauge if you think you may have issues as the factory electric sending units are notoriously unreliable.

 

It only does it after I drive a little bit, stays at 40 then gradually drops to 30 then 20. Sometimes it drops to zero and says check gauges. It's not making any noises other than when I got a oil change it makes a noise at start up. One mechanic told me he didn't here it. Only does it sometimes then kinda dies off after running for awhile

 

I'm really hoping it's just the cylinder head and I caught it in time! Is 600 to 800$ a good price for him to fix it?

 

I'd have your mechanic verify pressure with a mechanical gauge (or check it yourself, you can rent a gauge from most auto parts stores) you may have actual pressure issues (if it really is dropping to 0 that isn't good) or simply a bad sending unit (simple ~$40 fix).



That isn't a bad price, especially if it is for a new head (Figure $500 for a new head or $300 for used and 4-6 hrs. labor). If it is for a used head make sure it is a "TUPY" (corrected casting) from a 02-04 WJ (Grand Cherokee) or 02-06 TJ (Wrangler), another 00-01 head may end up having the same problem again in the future.