dfreeman616 Posted December 28, 2007 Share Posted December 28, 2007 over christmas, took the cherokee to illinoise to visit family. it's been losing oil but running fine. well in the last 130 miles it lost around 2 quarts of oil, mostly through the intake. did a compression test on it today, came up with the following (all numbers psi, spec is 120-150): cylinder......dry..........wet 1................57...........67 2................79...........96 3................90...........100 4................90...........105 5................87...........94 6................87...........91 also, warm oil pressure is about 15-20psi low at 1600-2000rpm :cry: looks like time for some engine work. i'm just surprised to find those numbers, still pulls 20mpg on the freeway. so, anyone want to analyze that info for me? edit: it's a 4.0l, 1988. Link to comment Share on other sites More sharing options...
Eagle Posted December 28, 2007 Share Posted December 28, 2007 Broken ring on #1? How many miles on the engine? Could also be a sticking valve, but that shouldn't contrinute to massive oil consumption. Those are rather poor numbers across the board. #1 being the worst is a surprise, though. Usually #6 is the worst. Link to comment Share on other sites More sharing options...
jtdesigns Posted December 28, 2007 Share Posted December 28, 2007 Broken ring on #1? How many miles on the engine? Could also be a sticking valve, but that shouldn't contrinute to massive oil consumption. Those are rather poor numbers across the board. #1 being the worst is a surprise, though. Usually #6 is the worst. wouldn't the wet vrs. dry reading be the same if the ring was broken? Link to comment Share on other sites More sharing options...
dfreeman616 Posted December 28, 2007 Author Share Posted December 28, 2007 it says 179,xxx miles. however, not really sure since i just got it a couple months ago. it's possible i have the numbers reversed, but only if my haynes manual has them reversed. i have cylinder one as the front by the radiator. i suppose i should say it's an 88 4.0l engine, just to eliminate any assumptions Link to comment Share on other sites More sharing options...
pingpong Posted December 28, 2007 Share Posted December 28, 2007 Sounds like you need a valve job, and rings. New bearings wouldn't hurt. Also verify that you really are only seeing that low oil pressure with a mechanical gauge... Link to comment Share on other sites More sharing options...
FxRacing282 Posted December 28, 2007 Share Posted December 28, 2007 hmm... engine work is not worth it. to pull a block apart you have to have the block square tested and have the crank put on a balancer and same with the cam. id say save up for a decent used motor and then when yours $4!t$ the bed drop the new one in. Link to comment Share on other sites More sharing options...
LEAD_NOT_FOLLOW Posted December 28, 2007 Share Posted December 28, 2007 I agree it looks really low, however compression checks really don't show a whole lot in my opinion. I'd do a leakdown test if your really worried about it. Anything over 20% shows a lot of wear... Link to comment Share on other sites More sharing options...
jtdesigns Posted December 28, 2007 Share Posted December 28, 2007 I agree it looks really low, however compression checks really don't show a whole lot in my opinion. I'd do a leakdown test if your really worried about it. Anything over 20% shows a lot of wear... Can you make a leak down tester?? I've looked for them and can't find them without its own compressor for like under 5 bills.... was thinking if you just had one of those small air tanks and a better gauge, hooked up to a hose from a compression tester screwed in to your plug hole you might be able to get a good leak down reading Link to comment Share on other sites More sharing options...
86FUBAR Posted December 28, 2007 Share Posted December 28, 2007 I agree it looks really low, however compression checks really don't show a whole lot in my opinion. I'd do a leakdown test if your really worried about it. Anything over 20% shows a lot of wear... Can you make a leak down tester?? I've looked for them and can't find them without its own compressor for like under 5 bills.... was thinking if you just had one of those small air tanks and a better gauge, hooked up to a hose from a compression tester screwed in to your plug hole you might be able to get a good leak down reading i agree with LEAD_N_F do the leak down , that should tell u more. u could make ur own but hear are some nice ones that are reasonable priced. u want the dual guage http://store.summitracing.com/egnsearch ... lse&N=+115 Link to comment Share on other sites More sharing options...
mjeff87 Posted December 28, 2007 Share Posted December 28, 2007 I made my own out of a compression tester hose and spark plug hole adapter fitting that came with it. Attach the fitting to a piece of air hose (I used a double barbed fitting and a couple hose clamps), set your air compressor to about 120 psi and use the pressure gauge on the compressor to watch for pressure loss. Kinda hack, but it works all the same. I used it to troubleshoot a 0 compression cylinder on a Ford Escort I had....ended up being the intake valve seat went bad on #4. As the pressure dropped, you could hear it hissing out of the intake manifold :cry: Jeff Link to comment Share on other sites More sharing options...
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