Start-up, no oil?

Hi Guys,

I have a 4.0, line6 from 1992 with 145K miles on it. I recently replaced exhaust manifold, water pump + thermos, plugs, O2 sensor, engine + transmission oils. It's been running great. And in many ways, it still does. Just this morning when I fired her up she made a pretty bad noise for about 2 seconds. It never did that before. I've never heard an engine run without oil, but this is what I expect it would sound like. Not good. When I got the jeep a couple of months ago I had a local shop with a good reputation check the rig out and change oils + filters. I double checked whether the engine oil filter has a drain valve in it and they assured me it did.

Now I usually park the jeep in the car port which is level, this time I parked it on an incline (front higher than rear). Could that cause the filter to get drained and thus the noisy start-up?

Anyway, I would really like to hear any thoughts on this sound. What could be causing it, how bad is this really?

Thanks,

Tim

Your filter could have a bad anti-drainback valve. Drop $5 and toss a new one on and report back.

As to how bad it is, it's never a good idea to intentionally run a motor w/o oil pressure, but if it's just a few seconds at startup chances are you won't do too much damage, but it only takes a split second to spin a bearing.

What brand filter ?

Ok, so a malfunctioning anti-drainback valve can really cause this? Pretty serious. Didn't know that that was so critical. Will get a new filter on there asap.

This local shop has their own brand filters. They assured me it was high quality and including an anti-drainback valve but I don't think that it is a big brand filter. Will check tonight and report back. If it's really the drainback valve on that *&^% filter then that's the last that those clowns at that shop have seen of me.

If I get the filter of, is there any way of checking that valve?

Thanks.

Tim

I don't know if you can check the function of the valve... maybe fill the filter up, put a plug in the inlet and turn it updide down for a few hours. Bad filters are not all that uncommon. I've heard of Wix filters having bad anti-drainback valves occasionally.

So what then are the really good filters? Fram?

Tim

Dear god no fram is horrible. Really goo but expensive is mobil 1. There was an extensive writeup on 4.0 filters online but I dont recall the website. Anyone know it?

Just get a Wix 51515. It's about 1/2 quart more than the stock filter, and among the best you can get. If you can't find them locally Napa are rebranded Wix also.

anodyne33 said:

Just get a Wix 51515. It's about 1/2 quart more than the stock filter, and among the best you can get. If you can't find them locally Napa are rebranded Wix also.

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How about a WIX 51773 (even longer)?

I run Napa Gold filters in 2 Jeeps and 1 Silverado and haven't had a bit of trouble out of them. The one I got for the Silverado cost me like $7.25 or so with tax.....not too bad if ya ask me.

Sounds good guys. I will stop by at Napa's on the way home to see what they have in stock. I really don't want to go cheap on this so I don't care about price so much.

So when I replace just the oil filter, I should pre-fill the new filter with oil right? Guess that's just gonna get messy, or are there any tricks?

Anybody know if it's common for the drainback valve to fail on filters this fast? This one's been on there for no more than 3 months, and maybe 2000 miles.

Tim

I don't bother filling up a new filter. It's not a bad idea, I'm just not concerned with the 2 or 3 seconds w/o pressure to deal with the mess.

I don't prefill but if you are concerned, disconnect the coil wire and ground it with a jumper wire and crank it for about 15 seconds.

I was a dealer mechanic for 13 years and never prefilled a filter on thousands of oil changes. But after an engine overhaul, I might crank with the coil wire grounded until oil pressure is indicated at the gage.

AlohaBra said:

I don't prefill but if you are concerned, disconnect the coil wire and ground it with a jumper wire and crank it for about 15 seconds.

I was a dealer mechanic for 13 years and never prefilled a filter on thousands of oil changes. But after an engine overhaul, I might crank with the coil wire grounded until oil pressure is indicated at the gage.

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This is still moving the pistons and causing premature wear. Pull the distributor. As this is turning the oil pump as well. Use a long screwdriver and put it down till it engages and turn. This will oil the engine without moving the pistons. You should do this before you start up a new engine, not after oil changes. I cut the handle off a long screwdriver and put it in a drill and turn it that way, much easier.

Matt

Hey you are right about that, with a new engine......I retired from the shop 10 years ago.

And it was longer than that when I built an engine with pistons.