oil pressure suddenly drops? [Archive] - Dakota Durango Forum

: oil pressure suddenly drops?


jburke311
04-14-2010, 03:15 AM
last week i too my stock 99 5.2l dak 4x4 w ith 77xxx miles wheelin, i got stuck n had to be towed out. i got some watter n maybe muck into the exhaust. so i drained the oil n used some seafoam twice into it. does anyone kno why my oil pressure keeps dropping once my truck is warmed up? when im driving at like say 1200 rpm the oil pressure is fine, but at idle or low speeds it drops. is it the oil pump or what? i have a full oil pan and im wonderin if just drainin a quart and puttin lucas oil stablizer will clean it out?

Harley
04-14-2010, 03:18 AM
I know in my 5.9 when I am moving, the needle stays in the middle, but when I come to a stop light or just sit and idle, it sits at the "L" until I get moving again. Not sure if this is normal but I do not seem to be having any problems (Yet)

Little Blue Guy
04-14-2010, 04:03 AM
You will need to install a mechanical gauge in the engine to measure actual oil pressure. Don't trust the dash gauge...you don't know how low "L" is or how high "H" is on the gauge as far as readings go.

You might have a plugged pickup tube screen.

timberwoof
04-14-2010, 05:44 AM
Plugged Tube is my call. Has happened to my rango before and it was sludged.

Harley
04-14-2010, 06:18 AM
Thanks for the info guys. Will need to check mine out when I get a chance.

hwystar
04-14-2010, 06:48 AM
The stock senders on these trucks tend to go for shit as well. The one on "booger" stays nice and high when your driving then drops to nothing at idle but the light doesnt come on. Or it drops and the light comes on. Or the light comes on and the guage reads fine.Or both read fine. As long as the lifters dont start ticking... I dont worry about it.

dkanderson
04-23-2010, 02:21 AM
my trucks doing the same thing kinda when its cold its at 40 when it gets hot and im driving it gose to maybe 30 35 and then at a stop it gose to the first line then slowly gose back up to 30 35 when i take off i really dont want to take the pan off looks like alot of work jacking the motor up and all.....where is the sending unit at? anyone got pics

primus454
04-23-2010, 03:10 AM
Sending unit is next to the distributor way back behind the intake manifold.

cindrango
05-03-2010, 02:08 AM
I had the same thing happen before.The Dwas under waranty.Tookit to the dealer.The pump was bad.They put in a new motor under waranty.That was 2 1/2 years ago.now this one is doing the same thing now.I come to a stop.The preasure drops to 0.The light comes on.Put it in Neutral.rev the motor.The Preasure comes back up.Im going to try the sender.Its not under waranty anymore.I dont feel like yanking the motor yet.

TurboBlew
05-03-2010, 02:33 AM
I had the same thing happen before.The Dwas under waranty.Tookit to the dealer.The pump was bad.They put in a new motor under waranty.That was 2 1/2 years ago.now this one is doing the same thing now.I come to a stop.The preasure drops to 0.The light comes on.Put it in Neutral.rev the motor.The Preasure comes back up.Im going to try the sender.Its not under waranty anymore.I dont feel like yanking the motor yet.

how did you verify the dealer put a new motor in? Did you take their word on it?

hskrRT
05-03-2010, 02:33 AM
I had the same thing happen before.The Dwas under waranty.Tookit to the dealer.The pump was bad.They put in a new motor under waranty.That was 2 1/2 years ago.now this one is doing the same thing now.I come to a stop.The preasure drops to 0.The light comes on.Put it in Neutral.rev the motor.The Preasure comes back up.Im going to try the sender.Its not under waranty anymore.I dont feel like yanking the motor yet.

Just a quick question, but how iis your oil level??

hskrRT
05-03-2010, 02:34 AM
last week i too my stock 99 5.2l dak 4x4 w ith 77xxx miles wheelin, i got stuck n had to be towed out. i got some watter n maybe muck into the exhaust. so i drained the oil n used some seafoam twice into it. does anyone kno why my oil pressure keeps dropping once my truck is warmed up? when im driving at like say 1200 rpm the oil pressure is fine, but at idle or low speeds it drops. is it the oil pump or what? i have a full oil pan and im wonderin if just drainin a quart and puttin lucas oil stablizer will clean it out?

How far does it "drop" And did you put seafoam in the oil?? If so, you may want to drain it again and re-fill with just 5 qts of good oil and skip the seafom.

MagnumDak
05-31-2010, 07:52 PM
I don't remember having this problem on my dakota but, I would get this checked out SOON. I had this same problem on my ram=motor replaced, broken rod. If it were me, I would either get it checked out or get the manual gauge.

Shimrra
05-31-2010, 08:23 PM
lol as long as there is some pressure it will live.

RebelX
05-31-2010, 09:39 PM
i had this problem with my 98 5.9L Rango. tried a new sending unit and said f this when it didn't work. installed a mechanical guage....now to get the check guages light on the dash to go out, lol.


oh. mine happened when i was towing my monte carlo home from south dakota, started flucuating around on me and oil level was fine.

94dakV8
06-01-2010, 01:44 AM
Just went through my 94 for same prob and it was sending unit. I hookd up mechanical gauge and had an avg of 50psi at speed and at bout 5-8 at idle. The 5.2 has 98k miles. I believe the spec frm my manual is 3-5 at idle. That low of psi is sure to make ur dash gauge drop considern it sees up to 60-70 and be in the middle.

Shimrra
06-01-2010, 02:00 AM
lol but look at the vange vs how much the stock needle moves.
where did you put the mechanical one? just took out the sending unit?

94dakV8
06-01-2010, 02:51 AM
Yea. I bought the cheapo gauge kit and it comes wit a fitting that screws into stock location. Then a compression fitting that holds the line in and then another on the back of the gauge. Simple.

RebelX
06-01-2010, 05:11 AM
if your going to make the mechanical guage a permanant thing i suggest going with a better brand than your local autozone/orielly's...etc cheapies. maybe autometer or something along that line. i wish i had, its my next step actually...wish i had a guage pod to put mine in actually.

94dakV8
06-02-2010, 12:46 AM
I plan on makn a custom instrument cluster later down the road wit sum digital gauges. I didn't even mount the gauge. Just used it to double check pressure. Now I don't even wory bout the stock gauge. Ill worry when it starts tappin. LOL

cindrango
06-26-2010, 01:06 AM
I found the reason for mine.The main bearings are shot.

9t9-5.2
06-26-2010, 04:52 AM
I found the reason for mine.The main bearings are shot.

That is usually the case when the oil pressure drops excessively at idle when hot.

CAM
07-31-2010, 04:59 AM
My 3.9 in my van just started doing this, though what happens is the "check guages" light comes on and oil pressure guage quickly drops to 0 then right back again. It does this over and over again throughout the whole drive. Will check the sending unit first and see what happens.