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JoeVit
Dodge Dakota
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11/25/2006
07:38:26
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 Subject: Oil Pressure
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Message:
I start my 00 dak v6 and the oil pressure is fine. I drove it for 15 minutes and it dropped to nothing. If I let it sit for a few minutes and restart, its ok for about 5 minutes. then drops again. I had the pan off and cleaned the crap off the screen and pickup tube and changed the pump too. I checked the pressure at the sending swith and its following the guage. The truck sat for over a year. Is there anything else that can cause this problem? I need to get this truck drivable. Thanks for any help.
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Richard
Dodge Dakota
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11/25/2006
12:32:54
| RE: Oil Pressure
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What is the oil pressure when you first start it? How cool is it outside. Usually the reason you have lower oil pressure when it warms up is because the oil heats up and is probably burning off. Is it smoking when it is warmed up? Does it use any oil? Do you have sludge buildup in your motor? I thought that somebody once said on here that 4.7s were prone to bad sludge buildup.
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JoeVit
Dodge Dakota
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11/25/2006
16:02:35
| RE: Oil Pressure
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pressure starts at above 40 then drops down to a little below 40. i ran a sludge cleaner thru it today. when i was done changing the oil and filter, it ran for an hour without a problem. so i took it for a ride and the pressure dropped to nothing again. doesn't use oil and no burning. its a 3.9 v6. how else would you clean it if it was a sludge problem? I really need help guys.
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daddio
Dodge Dakota
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11/25/2006
16:20:18
| RE: Oil Pressure
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"I checked the pressure at the sending swith and its following the guage."
i assume you used a mechanical gage to check this?
starting at 40 and dropping a little below 40 when warm is normal. it could be the relief valve in the pump is sticking or has some sludge stuck in it.
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jayb
Dodge Dakota
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11/25/2006
16:43:21
| RE: Oil Pressure
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he said it drops to nothing. the question for you is, DOES IT KNOCK WHEN IT DROPS? Run it for a few minutes after it drops to nothing, and see if it knocks. If it doesnt knock, you know its a sensor issue. If it does, shut that bitch off quick. There is a pressure relief in there. It keeps the pressure from getting too high. When that breaks, the pressure either drops to nothing, or gets way too high.
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JoeVit
Dodge Dakota
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11/25/2006
17:55:32
| RE: Oil Pressure
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yes i used a mechanical guage and it knocks when the pressure drops. and the pump is new. tell me more about this relief valve.
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daddio
Dodge Dakota
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11/25/2006
20:31:21
| RE: Oil Pressure
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it should be part of the oil pump assy. uses a spring and piston to regulate the oil pressure from getting too high. if a piece of trash would get on the sealing area the pump couldn't build pressure.
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OBIO3
Dodge Dakota
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11/26/2006
01:42:00
| RE: Oil Pressure
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Sounds like you have run the truck several times to test. Both driving and siting. If this is correct, I would have great fears there already is engine damage. Did you blow out the tube on the pickup screen? Also did you check the new pump to be sure all parts were in it. Of most interest is the presure relief valve plunger and spring. just because it is a new part is no guarentee it is assembled correct. Is this new pump by chance a rebuild?. If it is, change it for a new one. What's the chances you folded or tore the gasket during instalation? this could also give you presure when cold and none as oil thins out. Is the gasket missing where the relief valve is? I'm ruling out a pluged oil passage due to presure when first started. I'm leaning toward a malfunction of a sort and any one of the things I mentioned could posibly be your problem. How about your oil filter. Is it a fram or a rebadged fram with a totally defective by pass valve completely open dumping all the oil back into your pan? Or maybe it colaspe and is pluging off the oil delivery beyond that point. Right now your beating your head against the wall with nowhere to go without going back inside the engine other then installing a differant oil filter.
So many problems .... So little time
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JoeVit
Dodge Dakota
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11/26/2006
08:01:03
| RE: Oil Pressure
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Pickup tube was cleaned. I didn't check to see if all parts were in the pump. didn't know there was relief valve in it. don't know if its new or rebuilt. I used a dab of rtv to keep the gasket in place and I change the oil and filter again. Looks like I'm going back in to pull the pump out again. Pain in the assnow that the weather is getting colder. thanks for your help.
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JoeVit
Dodge Dakota
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11/26/2006
09:40:46
| RE: Oil Pressure
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another thing, the oil pressure never got too high on the dash guage.
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JoeVit
Dodge Dakota
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11/26/2006
15:16:54
| RE: Oil Pressure
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Message:
I have the pump off now. It looks like the pickup tube was loose. i swear i tightened it down enough. Could that cause my problem. How tight should it be and is there a threadlocker/sealer that can be used or should i crank it on as tight as it goes? i'm done for the day. gonna finish it tomorrow if you guys think that was it. I manually pumped oil thru the pump and it worked fine. thanks again.
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RichmondOiler
Dodge Dakota
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11/26/2006
20:36:40
| RE: Oil Pressure
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Pick up tube being lose will cause it to suck air and not pump oil. Crank down the jam nut and make sure its tight. While the pan is off and if you are competent, take off a rod cap and see what the bearing looks like. Should also check a main bearing as well. If the bearing is worn, the surface will be a copper color. Do this only if you know how to remove and replace the cap exactly as they came off. You must torque them to factory specs as well. If you are not comfortable doing this, then just put it back together and see if the oil pressure holds.
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OBIO3
Dodge Dakota
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11/26/2006
21:01:53
| RE: Oil Pressure
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One more thing. If you at times rev your engine out. use new rod bolts and nuts if you remove a rod. You will be looking for scrapy looking marks on the bearing. you will be looking for damage to the babit . This is the coating on the rod bearing that the crank rides on. Also look close at the crank for transfer of babit onto the crank. If you have any of these problems STOP right there. do not run the engine untill proper repairs are made.
The tube bolts are not all that big as you can reef hard on them but at the same time there is a torque specification you need to know. I have never seen one that never had a gasket between the tube flange and the pump. It will be a thin type gasket. Should have been one come with the new pump. If not go get one. It should say on the box if the pump is a rebuild or not. Check it out.
So many problems .... So little time
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OBIO3
Dodge Dakota
JOIN HERE
11/26/2006
21:10:00
| RE: Oil Pressure
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I forgot one importate item. Sounded like you used a dab of RTV just in spots. That may will have been enough to cause leakage at that serface also. Be sure you remove it completely. If your going to use something to kind of hold the gasket long enough to start a couple of bolts, use a THIN LAYER of vasolen on it. It will squeeze out nicely and it disapears soon as engine warms up. not like grease. Just remember, VERY THIN LAYER.
So many problems .... So little time
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JoeVit
Dodge Dakota
JOIN HERE
11/27/2006
02:52:17
| RE: Oil Pressure
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There wasn't a jam nut on the pickup tube when i pulled the original pump off. The tube was screwed into the pump. I don't think i should take off a rod cap. No experience inside an engine. i used a thin layer of RTV across the whole surface where the gasket sat. I'll get a gasket and a jam nut for the pickup tube and go from there. thanks
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OBIO3
Dodge Dakota
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11/27/2006
15:29:23
| RE: Oil Pressure
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Message:
JoeVet.read on the tube of RTV you used. It is NOT designed to hold presure. There is terific presure where you used it. It will not hold. You need to clean it out and replace that gasket also.
So many problems .... So little time
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JoeVit
Dodge Dakota
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11/28/2006
12:50:43
| RE: Oil Pressure
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Message:
Thanks for all your help guys. I pulled the pump and tightened the pickup tube. i cleaned the surface of the pump and put a new gasket in. took it out for a ride this morning and everything seemed to be ok. Pressure stayed above the midway mark on the guage and it increased when i accelerated. Thanks again.
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RichmondOiler
Dodge Dakota
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11/28/2006
14:18:49
| RE: Oil Pressure
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Glad to hear all went well!
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