|08-29-2012 10:52 PM|
I have a GMC, and a taurus with over 200,000 miles on them and have run nothing but Castrol dino oil, and fram filters. Not a drop of oil out the exhaust, or the seals.
Knocking on wood right now.
|08-29-2012 10:09 AM|
|08-29-2012 02:43 AM|
I've been following this thread as my 02 4.0L has been doing the same thing sort of.I can drive it all day and when I stop at a light the pressure will drop to about 20 or a little less but the check gauge light won't come on but if I was to turn it off to go into a store when I start it up again then the pressure is low the check gauge and chime comes on until I rev it up some then it's ok.The motor sounds fine with the low pressure and I have changed the sender with a mopar unit but still curious as to the problem.I will be doing a oil change with a K & N filter and 10-40 w oil because it doesn't get colder than 60 degrees here.
|08-29-2012 02:22 AM|
|scottunzicker||Jerry - Thanks, man. I'm going to continue with my plan of changing the oil/filer here soon and see what happens. I was also considering running a can of Sea Foam through it, just as a matte of course. Any problems with that?|
|08-28-2012 08:41 PM|
Scott, there is a possible scenario where a new, even a very high quality, oil filter could fairly quickly cause a low or zero oil pressure condition. Try this on and see if it fits...
Your engine might have had a heavy sludge build up if the oil hasn't been changed regularly, perhaps from a previous owner. The new oil could have been the type of oil that will clean out sludge which would have immediately clogged a high efficiciency oil filter like the Toughguard you used whose filtration efficiency is 99%. Sludge may not pack up a new lower efficiency filter like some discount filters are.
So if that's the case, the newly released sludge could have nearly immediately caused the filter to go into bypass mode which at idle could cause zero to low oil pressure. At this point, I would change the oil filter and then cut open the old-new oil filter to see if it is indeed packed with sludge.
If sludge is the root cause of the problem causing the filter to become packed and go into bypass mode, there may still be more sludge left in the engine that could conceivably pack up even another new high-efficiency filter and cause it to go into bypass mode too.
High efficiency oil filters like the 99% Toughguard or any other similar high-filtration filter can have that problem. A low efficiency discount filter may not because it may not filter well enough to clog up with sludge.
So it may take another filter or two before all of the sludge is gone if indeed that was the root cause. Cutting open the first filter and seeing if it is packed with sludge will be the proof or disproof to this theory.
|08-28-2012 07:13 PM|
I am going to say I agree with the replace your sender unit camp. My jeep does the same thing and has done it for many months. I haven't changed my sender unit yet because it doesn't really seem to be a very big problem. Sometimes my jeep will have the check gauges come on and then once I move it goes off. Other times I can drive for days and never see the light come on.
I would imagine you got a bad sender unit as Jerry mentioned above. You should be able to get your money back and I don't think it is very hard to replace, especially since you have already done it once.
|08-28-2012 05:22 PM|
I like Jerry, am not a fan either of synthetic oil, but some of you have it backwards, synthetic oils handle heat at higher temperatures better than conventional oil. There down fall weakness is that they deplete their TBN "TOTAL BASE NUMBER" quicker and lose their ability to nutralize the acid in the oil causing eroision.
As for oil pressure, these electronic guages are just relavent, and not accurate. Only a master guage through a air equipped line hooked directly from the engines oil pressure source is accurate. If you check it with a master guage, then you will get a accurate reading, which will help you to better understand if you have a problem or not.
Just my 2 cents worth, I HOPE THAT IT HELPS!!!
|08-28-2012 02:52 PM|
Purchase a real pressure guage and hook it up temporary and hang it under the dash. I had the same issue on one of my vehicles (not my Jeep), it ended up being the Bosch oil filter that I purchased from Autozone.
I replaced the sending unit with a oil pressure guage and ran the plastic hose inside and hung the thing under the dash. I went to Advance Auto and purchased a new oil filter and a replacement stock oil sending unit. I started up the car and it had no oil pressure, replaced the oil filter started the car again and at an idle it had 40psi according to the guage. I changed out the old sending unit with the new one and the idiot light didn't come back on. I have since permenantly mounted the oil pressure unit so if the idiot light comes on again all I have to do is look at the pressure guage, it won't lie.
Since then I only have purchased Purolator Pure One oil filters and have never had a problem.
|08-28-2012 02:45 PM|
|Jerry Bransford||The oil pressure gauge indicator's movement is dampened so it won't be twitchy with every minor engine RPM change. Plus cold oil is thicker when the engine is colder so pressure will tend to stay higher until the engine and oil warm up.|
|08-28-2012 02:42 PM|
|Gary2||the filter change I mentioned might not of cured it but it never went low enough to bring up the red check gauge light again . I just can't beleive that all the unsolved low oil pressure posts here and on Jeep forum I have seen lately is the oil pump . I have read where these engines run hundreds of thousands of miles for all of a sudden this many oil pumps to go sour . I agree something is flukie but as reliable as these engines are I have a hard time accepting the oil pump is bad , worn a little yea . Like Jerry said 10lbs per thousand rpm which confirms what most people were getting with their mechanical gauges installed. Even when it was 102 degrees out and the gauge on my daughters XJ said aout 0 and the light on that motor sounded as quiet as the day we bought it many years ago . I blame most of it on the filter on hers as her friend decided working in a garage he could save her money and did her oil change and thats when it started or got her attention being the light came on. The gauge may of gone low before with the MOPAR filter but not low enough for the red light to come on so she never knew anything was wrong . I am not saying that the MOPAR filter is anything great but I have never had an oil related issue with any of my Dodges or Jeeps so I stick to what has worked . What kind of filter was on it that caused it I don't know but I didn't like the size of it and didn't even notice any writing on it so I just figured it was a money maker for the garage that installed it . That wont happen again|
|08-28-2012 02:36 PM|
Why does the psi only fluctuate after the engine is fully warmed up and then why doesn't the psi fluctuate during every rise and fall of the rpms. I would guess the psi is fluctuating even when the engine is cool and during every acceleration/idle.
|08-28-2012 02:25 PM|
Jerry - No worries!!! I'm sincerely grateful for your input, and took no offense. I used to work in tech support, and I've learned that it's better to err on the side of presuming your client knows nothing and appear a little condescending than presume expertise.
I agree that, especially in hot climates, large swings of oil pressure are to be expected as the engine warms up. Again, I wouldn't be worried if the pressure wasn't ZERO and the check gauges light went on.
|08-28-2012 02:16 PM|
|08-28-2012 02:12 PM|
Jerry - Thanks for your feedback. I wouldn't be so concerned if the oil pressure gauge didn't drop to ZERO, and the check gauges light didn't come on.
Chris - I'll let you know how it turns out. It'll happen next week. This week is work and then headed out of town for the weekend.
|08-28-2012 01:41 PM|
Scott, oil pressure is supposed to vary up & down in direct step with engine RPMs and 20 psi at idle is actually very good oil pressure. The oil pump is driven by the engine so the oil pressure will always vary up and down in direct step with engine RPMs as they vary up and down. A common rule-of-thumb for good oil pressure is somewhere close to 10 psi per thousand engine RPMs.
At least that is true with a true oil pressure gauge as older model TJs came with. Newer model TJs had their oil pressure gauges reprogrammed so the normal ups and downs of oil pressure aren't shown so they don't unnecessarily alarm those who didn't realize oil pressure is supposed to vary.
|08-28-2012 01:37 PM|
I'm having a similar issue- bought a used TJ with 100k, promptly changed oil to Castrol GTX High Mileage 10W30 with a Fram ToughGard filter and now I occasionally (especially after running for 20+ minutes) see the pressure gauge drop about 15-30 psi to about 20 mark at a stop light or when the foot is off the gas for more than couple seconds. It hasn't hit 0 yet but I'm already looking around for possible solutions. I've seen the Mopar filter at a local Walmart and may give that a shot, even though it appears inferior to the ToughGard. Maybe the Bosch will be the way to go. I know I've read a lot of 'it's normal for the pressure to fluctuate' but the fact it's not always happening and doesn't happen for some Jeep owners causes me a little concern. Looking forward to the results.
|08-28-2012 11:57 AM|
|scottunzicker||So the plan of attack is to change the oil and filter (using high mileage blend and Bosch filter) and see what happens. If that doesn't do the trick, I'll try the oil pressure sending unit (again), maybe a couple of times... If THAT doesn't work... Oil pump?|
|08-28-2012 10:14 AM|
|08-28-2012 08:19 AM|
|Gary2||I too have been using synthetic since the early 80s in my cars,trucks , lawnmowers ...... I have just recently switched my 05 Rubicon to Valvoline VR-1 the gray bottle not the black " for Racing only ". I have been following the threads at Jeep Forum about the OPDA issue for the 05 & 06's 4.0. One of the things that made it seem like a good idea was switching Were the pictures of dry oil pans posted showing that the rear main seal did not drip as it did with mobil 1 as did mine . The other thing was it seems our motors are of an older design and and most of todays oil have moved somewhat away from some of the needs of our type of engines, in particular zinc so they said , I have no proof. I understand you can buy an additive but I just as soon use oil with it already in it while its available . I don't know if its true but as important as an "Oil Pump Drive Assembly" is I figured anything I can do to help prolong the life of I am going to try . Jeep wont stand behind the part and have not made an improved version although one is available else where which I have installed. I will say I too have eliminated the drip on the garage floor I had previously so I can see an improvement I am sure of|
|08-28-2012 12:16 AM|
|08-27-2012 11:02 PM|
|08-27-2012 10:53 PM|
|08-27-2012 10:36 PM|
|Gary2||I have been reading about a lot of this it seems this summer along with experiencing it on my daughters XJ . I swapped the sending unit , that did nothing , I cleaned out the oil passage to te sending unit as I read one person had a fair amount of sludge clogging up the small oil passage, did nothing . Changing the filter to a MOPAR filter is the only thing that had any effect on it . Once I switched the filter it never dropped low enough to turn on the check gauges light again . That was early July and have since switched to Valvaoline VR-1 oil which didn't change any of the gauge readings so all said and done the filter is the only thing that made a difference. Still runs fine almost 2 months later .|
|08-27-2012 10:14 PM|
|Wranglerguy48||The problem is that Jeep engines typically run at 210, normal operating temperature. Synthetic oil can not preform at these continuous temperatures and break down quickly. You should always use a good quality standard lubricant. I lived in Florida for a time and would run nothing under a 40 weight in that heat, even a 10 - 40. In my street rod I ran a straight up 50 weight from casterol, because of the high temperature climate and the high temperature operating temperature of the car.|
|08-27-2012 09:32 PM|
|scottunzicker||Well, I couldn't decide between regular, dino oil, or full synthetic. I've been a synthetic believer for many moons (ran it exclusively in my '00 VW GTi VR6 forever, and, when I sold it, the engine was still insanely strong, hence... ). So, with the I6 in the Jeep fixing to turn 100k, I figured high mileage dino/synth blend was a good compromise. Did I goof? She's running great, other than the low oil pressure issue.|
|08-27-2012 09:08 PM|
10W-30 should be fine for Austin. That oil will give you the equivalent of 30 weight oil at working temperature.
I am afraid to ask this question but, why did you use a high mileage blend? (I'm thinking that we may be zeroing in on the answer)
|08-27-2012 08:57 PM|
|scottunzicker||Full Spool - Yes... I neglected to mention that I went with high mileage synthetic blend, albeit at 10w30, which is what is recommended, from what I understand. Could that be the problem?|
|08-27-2012 08:27 PM|
|Full Spool||Maybe the oil is to thin for the climate you are driving in? The pump losing it's prime? If the gauge start working after a rev of the engine, possibly the sending unit sticking because it's Chinese garbage.|
|08-27-2012 08:23 PM|
|Jerry Bransford||I hope a bad oil pressure sender is all it is too, that would be a good thing.|
|08-27-2012 08:19 PM|
|scottunzicker||Thanks. I hope that's all it is... I've got a week long trip to Colorado in about a month.|
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