[edwatson1]

Hello everyone! I'm a new member with a 1991 Mustang LX 2.3L Convertible. I'm having an oil pressure issue at start up and at certain RPM's. It is taking anywhere from 45-90 seconds at start up to get an oil pressure indication on the gauge (sometimes a bit longer in real cold temps). I can hear the lifters ticking during this period, so it seems to verify that there is no or very low oil pressure. Once I have a good pressure indication, the ticking goes away. Yesterday, I was going down the highway and the oil pressure gauge went to zero. I pulled off the next exit and once the engine RPM's went below 1500, the gauge came back up. Over 1500 to 3000 RPM's, zero pressure on the gauge. Under 1500 and over 3000 RPM's, normal pressure reading. I do not hear any evidence of oil starvation between the 1500-3000 RPM range from the engine, so I'm guessing it is a sender or gauge problem. Still, the long interval of low or no pressure at start up concerns me. Where is the sender located? I may try changing it first. I did an oil/filter change last night, but have the same problems today. Any advise would be appreciated!

[b_chandler]

Sorry. Double post.

[b_chandler]

Trust the gauge. If the lifters are ticking, you've lost oil pressure. This very problem is the reason I got my '91 LX Hatch for free. The trouble is a clogged oil pump pickup. The o-ring style gasket on the oil pan deteriorates over time and the little crumbs of rubber find their way into the pan and eventually up against the pickup screen. It'll get worse with time if you ignore it. When I got mine, it needed a crank and one rod after spinning a bearing.

Mine's been in the family since new so I know the car's history. Orignally I thought the problem was sludge related and was hesitant to pull the motor apart and find a bunch of sludge caked everywhere and know that without getting rid of it the problem would return. So I tried a few things to prolong the inevitable(I was able to keep the oil pumping for 6 months or so) and time finally ran out when it lost oil pressure at highway speed and it spun a rod bearing. Upon disassembly, I found the insides to be spotless outside of normal varnish. The kicker was the oil pump screen full of black debris (sludge?...nope) It was crumbled oil pan gasket. One of Ford's better ideas I suppose.

Regarding the sender I'm still running on the original Ford sending unit and it reads just fine.

[edwatson1]

Thanks for the sage advice...I was thinking it may be because the pick up was getting plugged, but it dosen't make sense that I get normal readings at RPM's under 1500 and over 3000, and sometimes all the time. Looks like I'll have to bite the bullet and pull the oil pan, which I understand is a BIG job. Any advice on getting the pan off would be appreciated as well!

[mustangcar]

by the way when did ford start using this o-ring gasket, iknow they switch to a cast aluminum pan? mine is steel,,,,,thanks

[b_chandler]

Originally Posted by edwatson1

Thanks for the sage advice...I was thinking it may be because the pick up was getting plugged, but it dosen't make sense that I get normal readings at RPM's under 1500 and over 3000, and sometimes all the time. Looks like I'll have to bite the bullet and pull the oil pan, which I understand is a BIG job. Any advice on getting the pan off would be appreciated as well!

It's a weird anomaly. It was one of the reasons why my mother chose to ignore the gauge. "Well it was reading fine, then it quit and then came back." (as the car sits in my driveway with valve train clatter that sounds like marbles under the valve cover.)

There was a thread on Stangnet or The Corral that gave some pointers on oil pan removal without pulling the engine. It seemed to make sense, but it also seemed like alot of work. I did mine with the engine out of the car(for reasons mentioned previously).

Here's a tip: You should use a good gasket sealer in the corners where the pan curves over the rear main cap and the front seal retainer. RTV works good. Personally I like Loctite 518. My boating buddies and I use it to seal the crankcase halves on big outboards. Good chit.

[b_chandler]

Originally Posted by mustangcar

by the way when did ford start using this o-ring gasket, iknow they switch to a cast aluminum pan? mine is steel,,,,,thanks

With the cast aluminum pan came the o-ring. The aluminum pan showed up in 2.3 Mustangs in '91.

[mustangcar]

i think they went with a cast aluminum because of rusting pans,mine is rusting pretty bad,I painted it over the summer but I will need to replace it,,,thanks for the info

[b_chandler]

Doesn't everything rust in Kansas?

I've got an '88 vintage steel oil pan in my garage that came off of a junkyard Turbo Coupe motor that's rust free. Dent free is another story, but there's certainly no rust