My 1991 4.0 Explorer dumped about 3qts of oil on my driveway yesterday morning after I started it for the first time of the day. I got up under the engine to see if I could tell where it was coming from. It looks like its coming from the oil filter. The filter was loose so retightened it filled up with oil, thinking I must have not tightened it good last oil change(2 weeks ago). I started the engine again and it did the same thing. This time I could here something that sounded like pressure being let off and then the oil started flowing on the ground. Went back under and checked the filter again and it was loose. I am thinking there must be sludge build-up blocking the passage ways. I bought this 1 year ago with 122,000 on it and now has 138,000 with me doing 4 oil changes over the year. Does anyone have any suggestions on what I can short of breaking down the engine to clear this blockage. Maybe a machanical flushing machine. Any input would be appreciated.

 

Definately replace the filter. It is possible for them to go bad. The filter is the cheapest thing to try. I've also heard stories of oil filters bursting.

 

Thanks for the reply. I guess I forgot say that I did replace the filter. Same result I even torke the filter with a wrench.

 

gatown,Try this pull the oil filter drane the pan put new oil in and a can of oil flush in. see if it loosens up if not ,This is going to sound way out in left feild but it works. Get the motor hot drain the oil leave the filter on you will need 5 gal. of kerosene put the kerosene in the motor let it sit around 12 hours drain and replace filter and put oil in see what the oil presser is may need to do this 2 or 3 times. You can use the kerosene over and over. When done you can use the kerosene in a diesel truck it's cleaner then #2 diesel it wont hurt it .

 

Are you sure you got the old gasket out with the old filter? Sometimes the center threaded piece comes loose. Bypass located on the pump may be stuck closed. You could get some high pressure on these cold days. Most are running low on pressure at this age. If you didn't say it was loose I would have expected a sender leak. I'd do an oil change and put some very light weight oil in for a while and see if it gets unstuck. Dropping the pan is not something you want to do! The engine must be lifted.

If the high pressure bypass is stuck on this engine, I'd tap into the pressure sender and install an external bypass valve. These are set to 60#. At least temporarily install a pressure gauge. You can not diagnose this blind.

 

thanks dogman and Opera House Works it sounds like you both agree I should try changing the oil and filter and put in some kind of flush with it. I will give that a try this weekend, not enough time after work to do anything today. If that doesn't help maybe I'll try the kerosene trick. But will just pouring the kerosene into the oil fill distribute the kerosene throughout the engine or will it just drain down to the pan. I'm not sure how I will get the engine hot if as soon as I start the engine the oil is running out onto the ground? I wish there was a way I could force a cleaner up into the oil filter connection. thanks

 

A blockage wouldn't cause the oil filter to leak. The pressure relief valve on the pump would take care of that. I recommend a very thin oil so that the pump doesn't build up as high a pressure. A 2-3 of quarts of Mercon would thin some new oil out enough. Premix in a bucket and have it at indoor temp just prior to starting. Is it cold where you are? I assume temps under 30 causing the oil to thicken up. Still not convinced that there is not another problem. I think oil filters can take 100# easily for short periods of time.

 

gatown, pull the distributor ( get the motor on tdc before pulling the distributer) get a 1/2 in. drill with a 1/4 in. driver around 8" or longer fine a scocket that fits the oil pump shaft. Put the 1/4 in. in the drill a use the drill as the motor for the oil pump spend the pump up, this will let you work the problem, so you can see whats happening. This will also let you get the kerosene through the block to. May need to pull the valve covers to, to see how bad the slug is.