Sterek

I'm looking at buying a 1990 mustang GT I am wondering what would cause the kmember to crack the oil pan? The owner said the kmember had hit the oil pan causing it to crack.

imp

A fairly serious hit caused by a roadway obstruction could deflect the k-member where it's clearance from the pan is minimal. Loose connections of the member, it's bolted in after all, could have allowed it to move. I'd get under the car, inspecting exactly where this "crack" is. If this is a '90 5.0 engine, it's oil pan is stamped from steel: not "crackable" like the later engines' aluminum pan. Steel pans are puncturable, though, and that takes a fairly sharp edge to accomplish.

Does the engine run? Is there oil in it? If no & no, beware of an engine which may have been run while low on oil.

Sterek

The engine runs good, needs a tune do to having trick flow heads Cam and intake kit. Car just can't be driven far do the crack in the oil pan.

wbrockstar

I accidentally contacted the radiator support with the oil pan once during installation which caused a 1.5" long slit in the pan that resembled a crack.I was trying to force the hoist further to one direction to get the engine more in line with the motor mount holes in the kmember & the sharp horizontal portion of the radiator support must have been what got it.I wasn't aware of it until I got everything reinstalled,fill it with oil,primed the oil system then started it.I was checking for leaks when I found it.Believe it or not,JB Weld actually sealed the pan & to this day,it still doesn't leak.It'll be later before I can get a picture of the repaired area,to show where on the pan it actually occurred.I can't remember if it was on the rear sumped portion of the pan or the front close to the sway bar.I believe I had to drain the oil and let it sit a day until oil was no longer oozing out of the crack,sopping any residual oil up with paper towels.You want it to be clear of any oil and wipe the area down with a solvent to get any residue off.
If oil pressure is lower than normal once the engine is at operating temp,that can indicate bearing wear,possibly from being ran low on oil like Imp mentioned just from high mileage.As the main/rod bearings get more wear on them,from low oil,mileage,contaminants in the oil,etc,
oil pressure begins to drop because the clearance between the bearings & the journals goes up.

wbrockstar

Here's a picture of the JB Weld repair I mentioned.The oil pump is bolted to the block directly above where the repair was done.That may be why it didn't leak after the repair compared to how bad it may leak if the crack was located in the rear sump portion of the pan.

dawson1112

it would take a pretty good hit to cause the K member to contact the oil pan, so much so that the k member would likely be bent and need replacing. If they replaced it why wouldnt they have put a new pan on the engine. I suspect they dropped the engine when putting it in the car.

wbrockstar

I wonder if it was possibly the swaybar hitting the pan and not the kmember?? If the motor mounts were shot and the wrong length swaybar end links were used
the pan could make contact with the swaybar or if the engine was being installed with the motor mounts not bolted on,the pan could probably hit the kmember.It would also be helpful to see/know exactly where the damage is located on the pan.