is oil pressure ok??

[oljeeptek]

Originally Posted by kmerian

My problem is similar, lately when I have to stop quickly, the oil pressure drops very low and then recovers quickly, I have also noticed that if the engine starts to get too hot, my oil pressure will also drop. I have an 89 I-6 unfortunately I only have the dummy lights so I cant give exact readings.

Hey all. Keep in mind a few things...

Oil pressure always drops some hot. Most factory(Warranty) info suggest if you have at least 10 psi at a hot idle, and 30 psi at higher rpms, you won't have a problem. Yes, I also like a lot more, but they are technically correct. Use a manual pressure guage to be sure of the guage accuracy.

I personally don't like engine flush. I've seen it knock loose too much crud at once and wipe out bearings on very dirty engines. I drop the oil and filter, fill 'er up with transmission fluid, (Its basically very high detergent oil) and let it idle for a half hour or so to gently loosen things up. Then a fresh oil and filter change and it's good to go. Been doing this for twenty plus years with out a problem. Lubes while it cleans..


Oil pressure should turn on the check guages light, not the service soon light for emission controls. Sometimes people confuse them and look the wrong direction.

[DIGITRUCK]

Originally Posted by oljeeptek

I personally don't like engine flush. I've seen it knock loose too much crud at once and wipe out bearings on very dirty engines. I drop the oil and filter, fill 'er up with transmission fluid, (Its basically very high detergent oil) and let it idle for a half hour or so to gently loosen things up. Then a fresh oil and filter change and it's good to go. Been doing this for twenty plus years with out a problem. Lubes while it cleans..

Hey OlJeepTek,


Wow, you guys sure know alot! I have never heard of that trick before.

What do you think of "MARVEL MYSTERY OIL"? I added some to the Gas Tank and on my next Oil Change I'll add some to the Synthetic Oil.


Thx, Phil

[oljeeptek]

Originally Posted by DIGITRUCK

Hey OlJeepTek,


Wow, you guys sure know alot! I have never heard of that trick before.

What do you think of "MARVEL MYSTERY OIL"? I added some to the Gas Tank and on my next Oil Change I'll add some to the Synthetic Oil.


Thx, Phil

I've never been much of a fan of what we called "Potions and Voodoo". (Most highly touted cure-all additives don't usually do much.) I do like some JB and Wynns products.

I've never tried the Mystery Oil in a car, but I use it as an air tool oil religeously. Does wonders for them!

It's been my observation that quality name brand synthetics don't really need any additives

[broadbeltre]

Originally Posted by kmerian

My problem is similar, lately when I have to stop quickly, the oil pressure drops very low and then recovers quickly, I have also noticed that if the engine starts to get too hot, my oil pressure will also drop. I have an 89 I-6 unfortunately I only have the dummy lights so I cant give exact readings.

I have a 91 and when I first fire up, everything is right on. When I am driving around, it is around 20psi.

[demmo]

need to knoe if hot or cold

[oljeeptek]

20 psi hot and at highway speed is a little too low. 20 hot and sitting at idle is just fine.

[CENTREJEEP02]

Originally Posted by oljeeptek

Hey all. Keep in mind a few things...

Oil pressure always drops some hot. Most factory(Warranty) info suggest if you have at least 10 psi at a hot idle, and 30 psi at higher rpms, you won't have a problem. Yes, I also like a lot more, but they are technically correct. Use a manual pressure guage to be sure of the guage accuracy.

I personally don't like engine flush. I've seen it knock loose too much crud at once and wipe out bearings on very dirty engines. I drop the oil and filter, fill 'er up with transmission fluid, (Its basically very high detergent oil) and let it idle for a half hour or so to gently loosen things up. Then a fresh oil and filter change and it's good to go. Been doing this for twenty plus years with out a problem. Lubes while it cleans..


Oil pressure should turn on the check guages light, not the service soon light for emission controls. Sometimes people confuse them and look the wrong direction.

COuld be as simple as a sending unit - My 93 wrangler had one go bad and it took a 300 dollar oil pump and a weekend of intense labor before finding that out. The oil level would fluctuate wildly, spiking out and bottoming out in a random iterations. I would try replacing the sending unit before spending big bucks on a new oil pump. With that many miles though, it could be a bad pump as well. If the pressure isnt spiking, which it sounds like it isnt, things seem to be normal. If your emissions light is coming on, could be as simple as an O2 sensor...the Wrangler did that as well only it flashed codes at me on the diagnostic...

[Raimundo]

Originally Posted by amandazman

Hi, I have a 96 cherokee 4.0 Hi-output 4 WD with 167000 miles. When I start the Jeep it has about 65-70 psi oil pressure. After driving a bit, the pressure drops to around 50-55 while driving, and 25-35 psi at idle. I just bought this Jeep used and was wondering if this would be the cause of my check engine light to come on as it does. It will be off for a couple of days, then come on for a couple of days. Is there anything I should check before I get into real engine trouble?

You are o.k. 13 to 75 psi is the spect.it also depends on what oil grade you are using and the climate, but you are good.

[avmx]

Oil pressure is going to be greater during start-up because of the oil's resistance to flow. As the oil warms, it will flow easier, therefore reducing pressure. Once the oil has warmed and stabilized, the pressure becomes a function of RPM. The lower the RPM, the lower the Pressure, just as if the RPM were higher, then pressure will be higher. This is all normal. The erratic pressure readings can be attributed to a bad sending unit. To verify this, connect a secondary gauge to verify proper operation.

[citizen@large]

I've got an '89 4.0l Selc.4x4 Laredo and my oil pres. guage stays pegged at all times...

I'm thinking the sending unit or the wire(s) on it. Problem is, I can't seem to locate the badboy...

Anybody know where i can find it??? Thanks!

[AlohaBra]

Yeah...the sender is on the oil filter housing by the distributor.
Disconnect the wire and it should be no pressure. If it is still peged then the wire got grounded or your meter is sticking or bad.

[longfellow]

always remember that eng. temp. effects oil viscosity. the hotter the eng.
gets' the thinner the oil gets. so at higher temps' oil pressure reads lower.

I had a ply voyager that did the same thing but she was bloweing blue smoke at start up. Oil pressure readings varied all over the place.Rings were bad. I ended up putting in a 33k eng. block. Original had 93k on it and original owner was useing 10w40 to help keep oil at a thicker viscosity.

but that was my problem doesn,t mean this is your situation.

[citizen@large]

Hey, thanks Bra, I just cleaned up the contacts a little and I've got preassure readings... Nice to know that I don't need a sending unit now...

[IrishChef]

The oil pressure sending unit is cheap and easy to replace....your symptoms sound like it could be that. Start with the easy stuff.

[citizen@large]

I said the hell with that rig a while ago chef. Got me a beefy '98 now, but thanks! ps- no more guage probs...