CEThomas Posted July 13, 2007 Share Posted July 13, 2007 Well started the 4.0 up to night and for the first 60 sec heard a rod then it went away and could not get it to do it again. Heard it the first time we started the engine but it was only for the first 30-60 sec. and went away and did not do it again till tonight. Quick check of the compression found the following: 1=80# 2=110# 3=105# 4=110# 5=100# 6=80# Also the new plugs that we put in were white :cry: I have not been around the Jeep 4.0 till this one, do they have this problem till the oil pressure is up to speed? Going to check the oil presssure this weekend and see what it's running at, but looking like I may be doing some engine work :cry: Link to comment Share on other sites More sharing options...
ejndssn Posted July 13, 2007 Share Posted July 13, 2007 need to determine if a lifter is a suspect since they are hydraulic… this may be one of the causes that you hear after the initial start up . Try to isolate the source of the noise if its at the top of the engine or on the bottom. Leaky lifter or spun bearing could be a possibility. :cheers: and if you decide to change out the eng have it stroke you will not regret it. :cheers: Link to comment Share on other sites More sharing options...
CEThomas Posted July 13, 2007 Author Share Posted July 13, 2007 It's from dead center, but it stops prior to getting close enough to find it :headpop: And yes its about the time it takes for a lifter to pressure up. After start up it's runs good, no smoke and good power. I want to check the oil pressure this weekend to see if the oil pump is week as I do not trust the dash light ;) Link to comment Share on other sites More sharing options...
Eagle Posted July 13, 2007 Share Posted July 13, 2007 You are providing data unrelated to the reported problem. Compression has little to do with oil pressure, and nothing to do with rod knock. First point: are you sure the noise you heard was a rod knock, or could it have been a valve lifter tapping until it pumped up with oil pressure? You have two non-adjacent cylinders with compression that's below what it should be. Was the compression measured with the engine hot or cold? Did you try squirting some motor oil into the low cylinders are checking the compression again? If they stay low, you need rings. Rod bearings can be replaced in the vehicle just by dropping the pan. If the noise is a wrist pin, however, the pistol and rod have to come out. All of which is unrelated to compression. Link to comment Share on other sites More sharing options...
mjeff87 Posted July 13, 2007 Share Posted July 13, 2007 FWIW, my Ford Escort does the same thing when the oil gets about 2500 miles old on a cold start in the morning (and is a gentle reminder for me to change it at 3K ;) ). On it, I know it's the lifters, but without hearing yours I couln't offer a diagnosis, only a possible cause. Jeff Link to comment Share on other sites More sharing options...
CEThomas Posted July 13, 2007 Author Share Posted July 13, 2007 You are providing data unrelated to the reported problem. Compression has little to do with oil pressure, and nothing to do with rod knock. First point: are you sure the noise you heard was a rod knock, or could it have been a valve lifter tapping until it pumped up with oil pressure? You have two non-adjacent cylinders with compression that's below what it should be. Was the compression measured with the engine hot or cold? Did you try squirting some motor oil into the low cylinders are checking the compression again? If they stay low, you need rings. Rod bearings can be replaced in the vehicle just by dropping the pan. If the noise is a wrist pin, however, the pistol and rod have to come out. All of which is unrelated to compression. Compression test was done with engine warm and just to check the general health of the engine as it was time to close shop and I did not want to do much else on it. And no I did not put oil into the cylinders, just wanted a quick check till the weekend. The compression is not a big thing but if I am going to have to do anything to it might as well pull it out and do it right. No use to patch a tired engine. It could be a lifter, it was around #3 and #4 and sounded about mid engine on the right side. It's also getting oil to the top when I looked in the fill hole but sure could be a lot better. I had a 3.0 in a Carvan that could not hold oil and the lifters had to pump up each time you started it. as the oil pump started to go it took longer for the lifters to pump up :nuts: It was not as loud but it was a v-6 and not a L-6. Which side is the lifters on the 4.0? Link to comment Share on other sites More sharing options...
mjeff87 Posted July 13, 2007 Share Posted July 13, 2007 passenger side of the block Link to comment Share on other sites More sharing options...
CEThomas Posted July 14, 2007 Author Share Posted July 14, 2007 That is the side it came from. Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted July 14, 2007 Share Posted July 14, 2007 4.0L are known to have noisy valve trains... Mine MJ gets a little tick at idle when it gets warm. It also gets worse the older the oil is. The first week or so after an oil change you hear nothing. Then it gets progressively worse until its changed again. Just rolled to 80,000mi. I have probably had a dozen of them. Some are better and others worse, but all in all, this is pretty much the way life is with the 4.0. CW Link to comment Share on other sites More sharing options...
ejndssn Posted July 14, 2007 Share Posted July 14, 2007 :agree: with CW 4.0L are known to have noisy valve trains... I've have 2 XJ's(89,96) and 1 MJ(89) Almost had an YJ but the wife x'nade and even with the MJ stroked just learn to live with it and monitor for any additional noise. :brows: Link to comment Share on other sites More sharing options...
Eagle Posted July 14, 2007 Share Posted July 14, 2007 It certainly sounds like a lifter. If it was either a rob bearing or a wrist pin, it would be worse/louder when warm because the oil is thinner. It wouldn't go away. Be sure you use an oil filter with a good anti-drainback valve. Whatever you do, don't run Fram oil filters. Link to comment Share on other sites More sharing options...
CEThomas Posted July 14, 2007 Author Share Posted July 14, 2007 NAPA silver--- well now they call them NAPA NASCAR filters :nuts: I also just found out that I dumped the wrong oil in it, 5w-30 and not 10w-30 :oops: Link to comment Share on other sites More sharing options...
Eagle Posted July 15, 2007 Share Posted July 15, 2007 I ran my '88 XJ on 10W40 from the day it was new. I switched over to 15W50 synthetic at 175,000 miles. That was Mobil-1. I later changed to Castrol and they don't have a 15W50, so now I run 5W50, or 10W40 if I can't get the 5W50. Link to comment Share on other sites More sharing options...
CEThomas Posted July 15, 2007 Author Share Posted July 15, 2007 This 4.0 has around 200,000 I think. So maybe I should bump it up also. Link to comment Share on other sites More sharing options...
carnuck Posted July 18, 2007 Share Posted July 18, 2007 I run NAPA brand 15W40 synthetic (since I work there) but make sure you don't have a Fram filter! So far in the past 3 years, I have documentation of 11 AMC motors killed from PH11s collapsing and a letter from Ford stating that if your (diesel powered) vehicle comes in for warranty and it has a Fram filter on it, your warranty will be null and void due to the frequent internal collapsing of the filters on cold start up with 15W40 oil. Link to comment Share on other sites More sharing options...
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