Hello,

A little background, I have a 2002 F-150 with a 4.6L 4x4 automatic. The truck has 84,847 miles, 3 inch lift and sits on 35's and I plow snow with the truck. I only drive the truck 2 or 3 times a month for about 100 miles or less.

The last couple times I have driven the truck, I have noticed after the engine comes up to temp, that at idle sitting at a red light the oil pressure guage would drop to 0 and the warning light would come on. If I tapped the gas, the gauge would start reading again and the light would turn off. I checked the oil and it was ok. My last oil change was about 4,500 miles ago.

Well while driving the other day the oil pressure light started coming on again while stopped. After driving the truck for about 30 min on the highway, I was merging onto the exit ramp the engine shut off. The engine made no noise and did not blow any smoke. I did not know it had stopped until I did not have power steering on the ramp. After stopping the truck, I tried to crank it over to restart the enigine. The engine would not turn over but I still had plenty of battery power. I had the truck towed to a ford dealership and after several hours, I was told by the service rep that the engine was locked. He could not provide any idea of what locked it up and siad it needed a new engine for $5800. When I asked bout havin the engine taken apart to locate the problem he stated it was not worth it and I should just buy a motor.

So with that advice I towed the truck to my house to have a look my self. I have tried to turn the engine over with a ratchet and breaker bar and could not turn it clockwise or counter clockwise. The engine is still filled with oil and coolant and the oil does not smell burnt or look metalic. When it stopped the truck lost no fluid and nothing leakes.

Well there is my problem. So I guess I am looking for anyone with any idea of what could have locked up my motor or if it is even locked up, Is there anything else that could have happened? I will probably pull the engine out of the truck in the next couple days so any ideas would be great thanks in advance.
Brian

 

Sounds like the oil pump could have failed.

 

Well, best guess over the internet sight unseen is that you lost oil pressure either for good, or you lost it enough to damage a main bearing and it finally wiped and seized the engine. It could have been a rod bearing, but normally the other 7 cylinders wil overcome a single rod bearing failure, witch you should be able to hear as a rod knock.

A good direction to go - pull the spark plugs and look for coolant. Try to turn the enigne over. Nothing? no coolant? No turn over? well then drop the pan, pull a couple of main caps / rod caps and look for wiped, blued crank journals or blued rod journals.

Either way it sounds like it is rebuild / repalacement time.

David

 

I have to agree that it sounds like a bearing half slipped over the other half. But first take the belt off the engine and see if you can turn it over I have seen engine changed out because the alternator locked up same for ac idler bearing. I have had them slip a rod bearing and never make a sound just quit and slide the tires on a standard shift. it could have been either a pump or oil filter failure. Good luck

 

thanks for the help, well no collant when i pulled the plugs and I still cant turn it over by hand. So the next step will be pulling the engine. Any sugestions on rebuild it or replace it? and any good places to buy a new engine?

 

Until you get it out and see whats wrong you don't know whether to rebuild or replace. Here lately it has been cheaper to replace then rebuild these motors.

 

Stuck bypass valve in the oil pump, I'd bet. This is sounding very familiar

You didn't use any Lucas stabilizer in it ever, did you?

 

no only penzoil 5w30

 

Hey tprbrian--How about a followup? What did you find out with that locked up 4.6?