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General Forums => The Mess Hall => Topic started by: jmhat98 on April 23, 2006, 12:21:47 PM

Title: oil pressure
Post by: jmhat98 on April 23, 2006, 12:21:47 PM
I am working on the jeep today, I changed the oil pressure sending unit because  that is where I think my leak is coming from, but now my oil pressure reads different. It used to go from 40 to 80 depending on rpm, but now it stays within 60-70 no matter what, it does move but only in that range. Is this normal, what do you get for pressure? Are ther specs on how tight to tighten the sending unit Thanks?
Title: oil pressure
Post by: Jeffy on April 23, 2006, 12:27:46 PM
You can put some teflon tape on the threads to keep it from leaking.  Otherwise, I just tightened it till I felt it was tight.  I didn't crank down on it though.  The difference could be because it was leaking or it could be because of variances with the senders.  As long as it's consistant, I don't think you should have any problems though.
Title: oil pressure
Post by: jt04GT on April 24, 2006, 08:48:36 PM
What engine? 2.5?  Normal average pressure should be around 35-45, that's why the gauge has 40 straight up in the center, like all the other gauges, that is the normal expected needle position.  A true 60-80 would probably blow something out, try a new Mopar sending unit,  My old one read 75-80, 35-50 tops after replacement.
Title: oil pressure
Post by: wrangler387 on April 24, 2006, 09:08:30 PM
idle oil pressure when warmed up according to the haynes manual i believe is around 25psi. The oil pressure should increase though as you go through the RPM.
Title: oil pressure
Post by: chardrc on April 26, 2006, 05:40:21 PM
lol my oil presure gause or sending unit is broken and when you first turn it on it works fien but as it warms up it starts to say i have negative oilv presure... lol oil vacum.... aw just one of the many little things i still need to fix on my jeep
Title: oil pressure
Post by: Erik on April 26, 2006, 06:15:35 PM
just replaced my sending unit.  didn't use any teflon tape on threads of new one.

reads about 20 psi at idle, 40 psi while on the throttle.  when it's cold everything reads slightly higher.
Title: oil pressure
Post by: wrangler387 on April 26, 2006, 06:23:46 PM
I didn't use any tape either, glad its all working good for you  8)
Title: oil pressure
Post by: jmhat98 on April 26, 2006, 06:57:43 PM
Mine is still reading high after a new sending unit, what could be the problem?
Title: oil pressure
Post by: wrangler387 on April 26, 2006, 07:02:12 PM
You could have a build up/clog somewhere. Have you ever ran any sort of engine cleaner?
Title: oil pressure
Post by: Yellowcritter on April 26, 2006, 09:19:07 PM
Quote from: "jmhat98"
Mine is still reading high after a new sending unit, what could be the problem?


Not sure if this is true or not, but it's info I got from a service guy at a local dodge dealer when I was having prolems with a sensor. He told me to use only sensors from the dealer as they are made for specific year models as to where some of the aftermarket dealers will make one sensor for all year models with the same size engine and the ECM will read them different.  I know this fixed the prob with a temp gage I was having.
Title: oil pressure
Post by: Jeffy on April 26, 2006, 11:57:24 PM
The senders are made by the cheapest supplier that's able to make something that works most of the time.  They are probably the same makers of the ones you buy at any Autoparts store.
Title: oil pressure
Post by: Yellowcritter on April 27, 2006, 11:15:29 AM
Quote from: "Jeffy"
The senders are made by the cheapest supplier that's able to make something that works most of the time.  They are probably the same makers of the ones you buy at any Autoparts store.


Your half right, most manufactures make products for many different companies. But each company has their own specifications that the manufacture has to meet, so in between each companies production the manufacture has to retool the assembly line to meet those requirements.

So one factory might make sensors as an example for 5 different companies and each is different. And yes most companies contract out the manufacturing of their parts but it is not always to the cheapest bidder because they might not be able to meet the requirements of the company. And there are company standards that have to be meet as to how much of a return is expected from none working parts which is usually set some where in the 90% plus range. Most companies could not operate on a most of the time and stay in business.

A wife's employeer is a metal fab company and they make conveyer and retooling sytems for many national and international factories. They too have to be able to meet these same requirements for the process.

So what the service tech told me made since and worked, it was just easier to go with a shorter post last time.
Title: oil pressure
Post by: Jeffy on April 27, 2006, 11:37:11 AM
Ok, maybe not the chepest, but they are prone to failing and do often.   :lol:
Title: oil pressure
Post by: Yellowcritter on April 27, 2006, 02:15:42 PM
You get what you pay for ... so the cheapest may not be the best. Besides I would rather spend my time on the trails than working on the jeep. Unless the work is actually play by adding a new mod.  :D Which usually means spending more money too.

jmhat98 ... good luck with the sensor problem, let us know when you figure it out.
Title: oil pressure
Post by: Yellowcritter on April 27, 2006, 02:30:48 PM
Just got a email from a machanic friend, he said do not use teflon tape (Didn't say why) and he also said the same as thing as Wrangler387, to maybe try a engine flush or cleaner if you had already tried replacing the sensor more than once.

He also said he wouldn't mind taking alook at it, but I'm not sure if we're anywhere close to you
Title: oil pressure
Post by: Jeffy on April 27, 2006, 03:53:19 PM
The reason for not using teflon tape is because not everyone knows how to use it properly.  If you have too much hanging off, it could get into the oil lines and cause problems.  You shouldn't need to add any if you have it on tight though.
Title: oil pressure
Post by: pedrolobo1978 on July 06, 2006, 02:15:46 PM
I seem to be having the same negative oil pressure problem someone else posted.  I haven't tried a new sensor yet but have a few questions about sensors.  First is kind of a no brainer, should oil be leaking into where the wire connects to the sending unit? I assume this sensor is broken and is what is causing my negative oil pressure readings.  The second question I have is about another sensor I know is broken but do not know what it is called.  I have a 2.5 liter in a 1992 wrangler and there is a sensor on the rear driver side of the head which attaches next to the valve cover.  Thanks for any feedback.

Pedro