258 oil pressure problems

[sloop]

Well, my first week of driving my '82 Wagoneer and I have been noticing some problems and weird things with the oil pressure. Last night I made sure I had the oil level correct..

Tonight, I fired up the engine and the oil pressure came up to 40 psi. I dropped the shifter into drive, still 40 psi. I stop at a stoplight about a mile away, and its down to about 35 while holding it in drive and idling.

By the time I get home, fifteen minutes later, when I idle in drive the oil pressure goes down to absolutely zero, but it will come up to 10-15 when in neutral (faster idling). It increases as I rev the engine.

Looking for ideas on what could be causing this? Is it a valve? Do I just need a new oil pump? any input would be appreciated, thanks

Mark

[bigwillys]

Hot oil pressure problems are USUALLY Main or cam bearings, not pump-related problems. I had a 258 in a CJ that ran for a whole year (12,000 Miles) with way less oil pressure than that, and my current 360 in my 88 runs about the same. I'm not saying that it doesnt matter, just that you Can keep driving it as it is. good luck

[sloop]

OK, thanks bigwillys, sounds like I'll try switching to a heavier oil and see what happens (I was using valvoline 10w30).

[kyjman]

Changing the weight of the oli wont help....the main bearings are worn, and it wont keep pressure. My 82 J-10 with the 258 runs almost the same oil pressure...max after warm up is 0 at idle, and up to almost 10 psi at 55 mph......its been this way since 1998, and I've put 34,000 miles on in that time. Also I would jump in it today and drive it anywhere, and know it would make it. That 258 is one heck of a good motor.... :D

[Wagoneer622]

I would't worry about it, my dad's old 79 Cherokee and our 85 Grand Wagoneer did the same thing as you describe. They both had 258's. I would have to agree they are a great motor!!! Keep driving it, when it starts making weird noises from the bottom half then it will be time to worry. How many miles are on it? Good luckk with it.

Chris
83 Wagoneer Ltd.(360/727/229)

[Lugnut]

It does seem that with the in-line sixes' especially, that there are TWO oil-pressure readings -- SOME and NONE!
If a goodly number of your lifters aren't clicking (maybe one or two, you're probably good to go for quite some time, but I wouldn't try to pull several thousand lbs. with it.

[flipsalot]

Geez I was gonna ask you guys if 20 psi was enough after warm up(258 in my cj-8)...lol I guess so after reading the above :eek:
-James

[sloop]

Well there are about 154,000 miles on the vehicle, the last owner says the engine was rebuilt at 90k, but I don't know what that rebuild included. :confused:

The engine is definately noisier than the 258 in my CJ-7, but I don't think the noises come from the bottom.. they sound more like clacking, maybe the valvetrain, I'm not good with engine internals. I don't mind the noises though, I like hearing the engine work :D

I plan to just keep driving it.. then when it finally dies, maybe I will have found a 4.0 mpfi, or just swap the 108k 258 engine from my CJ-7.

[Alaskaman]

Once upon a time had a bad sender that exhibited those symptoms, on a 258. Try a mechanical guage or substitute a known good sender to know for sure. New sender was about 20 bucks, heck of a lot cheaper than bearings. :D

[flipsalot]

Hehehe thats the way I look at it! When it deis..fix it. :D

[Max Power]

Hi everyone,
I know this discussion is mostly centered around straight 6 engines, but my 360 takes about 10-15 seconds to go from 40 psi to zero when I'm fully warmed up and in "drive" at a stoplight. Taking it out of gear and revving up to 1000rpm gets me back to 15-20 psi. No problems when moving (unless it's at an idle, then same problem) I am running 10w-30. Otherwise the engine runs good and strong. although I do have a little valve noise coming from #8.

I was going to replace/rebuild my oil pump, but after reading your posts, (bad bearings etc.) now maybe I should replace/rebuild my engine.

any thoughts would be greatly appreciated!!

thanx,
Robert

[Bob N]

Hey, RK I put new gears and a relief spring in the oil pump on the Waggie and I get 70 psi cold with 20W50 oil. Didn't help the valvetrain clatter though.. :confused: Of course, after 194,000 miles, it might need a rebuild :rolleyes:

[Crazy_Jeepman]

I have had several 258,s that run a 0 at idle oil pressure. Run great, except for the lifters clatering. After checking it out, I found thrust bearing to be wore out. Twice I was able to polish the crank and install new rods and main bearings. This increased oil pressure to normal range and lifters fell silent. So if engine runs good other than no oil pressure this would be the answer. To check for thrust bearing problem, pry harmonic balancer towards engine then try to pry it forward. If ANY movement is seen or felt it is the thrust bearing, the 258 has a 0 crank endplay. Sometimes the harmonic balancer can be seen moving forward and back when running, idle it, then rev it, idle, rev, idle, rev while watching the balancer, it will move forward and back if thrust bearing is wore out. If a standard shift it is easy to see any wear, at idle have someone push and release clutch several times, this will also move the balancer forward and back if the thrust bearings are wore out.

[desert_freak]

CJ that is the best info I have seen yet on the I6 oil pressure problem. I get about 40 cold after about 30-60 seconds and it falls to around 5-10 at idle-warm. This is with 10W-30 right now and some Marvel. I was using 20W-50 in the summer, got slightly better pressure but clatter was pretty loud. I started trying lighter oils and first Rislone and finally marvel. I truely believe that the valve train is slightly quieter now and is the quietest with the 10W-30. My lifters will pump up and quiet down for short periods when I come to a stop. I'm going to check my play like CJ instructed!


P.J.

[ February 18, 2002: Message edited by: desert_freak ]</p>