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I have a 2004 Jeep Grand Cherokee with a 4.7l v8 that has been having oil pressure troubles. The jeep has about 143,000 miles on it and I usually change the oil every 4,500 or so miles. A few days ago the check gauges light popped on my dash and the oil pressure gauge was reading near zero, but it promptly went back to normal for the rest of my ~30 mile ride home. Now the oil pressure is fine for a few miles, between 15 and 20 or so, before the pressure drops to zero and then followed by it going between about normal and zero for the rest of the ride. The pressure gauge has never been higher than what it has usually always been. I took it to my shop and he figured it was likely the pressure sending unit which he replaced but it was still doing the same thing. He tested the oil pressure and said that it starts at 50lbs but drops sporadically after running at 2000 rpms to around 5lbs. He is suggesting that I have a blocked pickup screen and an excessive amount of sludge/sediment in my oil pan. He wants to drop the oil pan to clean it, and either clean or replace the pickup screen if it is too bad to clean properly. He gave me a quote for the work involved which was $143 in parts plus about $50-60 if I had to replace the screen. This includes a new gasket set, 6 quarts of oil and oil filter. The labor involved is quoted at $413. I can't afford $5-600 of work right now, so I called a friend of mine who is also a mechanic and he suggested a few other options. Option one is to use some seafoam in the oil and to idle it for a short while and then get the oil changed to clean out the gunk. Option two is to just get the oil changed to see if that clears it out on its own. Option three is to get the oil changed, but after its drained to get the pan and pickup screen spray cleaned to get the gunk out. Now, I know almost nothing about cars so I have no idea how effective any of these things will be which is why I turn to AI. What do you all suggest I do? In the meantime I'm not driving the Jeep at all so I don't kill it.
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| # ? Mar 5, 2013 19:42 |
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| # ? May 21, 2013 18:54 |
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Yes, those are all valid options when done properly. Whether it works or not, or even if the original mechanic's diagnosis is correct is a different story. But trying some seafoam (or just a quart of ATF) in the oil and idling it up to temperature and then changing the oil and filter is a good start.
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| # ? Mar 5, 2013 19:45 |
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I just did an oil pressure sender on one of those yesterday. From what I've read, the senders can be flaky and lovely. I'd see how cheap one is and just throw it on. Go from underneath, you can pull the oil filter for a little bit better access if you like. Theres a red security clip that needs to be clipped out like an injector harness retainer, then its a simple matter of a 1 1/16" deep socket and appropriate wrench.
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| # ? Mar 5, 2013 20:00 |
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Number one, do an oil change. See what comes out. Do you see chunks? Do you see sludge build up on the drain plug? These are signs the diagnoses is correct. Get a flashlight, peer in the drain plug, look for signs of build up on anything you can see. I'm betting you'll find some. If it looks clean though, the diagnosis is in doubt. If you'd like to try to fix the problem without dropping the pan, poor ATF in the crankcase with the engine oil. It's gonna work better than Seafoam for breaking down sludge deposits. You'll have to run the motor a while with it in. Make sure to get it good and hot. Another good solvent is diesel fuel, which is technically an oil. It will of course reduce the weight of your oil (IE: 30W oil might become 20W with an additional quart of diesel added). This can cause lower oil pressure in itself since thinner oil naturally reduces pressure, the point is though is to break down the sludge deposits that are clogging the pickup screen and either drain them out with another oil change or get them caught in the oil filter (which you will also change out). If however the stuff clogging the pickup screen (if indeed this is actually what is happening), is bearing material, then you are out of luck, the motor is on it's way to eating itself. Also, please note that oil pressure problems are serious, if they are real the $500 needed for a pan drop and screen clean will look cheap compared to engine rebuild time.
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| # ? Mar 5, 2013 21:30 |
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