loud engine knock

[99fordexplorereb]

im fixing to buy a 99 explorer Eddie burar edition for 500 from the shop i work at, it has a loud engine knock and when it cranks over i hear a scraping sound, it has the 5.0 v8 engine, it also has 225k miles and the oil is extremely black, im curious, what are the chances that its just a oil pump? engine starts fine other than what i mentioned

 

[koda2000]

oil pumps don't knock. spun bearings because an oil pump is no good will knock, but once an engine is knocking it needs a rebuild. cheaper to find a good used 5.0L engine and swap it out. $500 isn't bad if the rest of the truck is in decent condition. figure scrap value is around $350 so it's only costing you $150. 5.0L motors are plentiful and cheap. can you do the work yourself? if so, you might have a good truck for around $1000. the Ford 5.0 is good for 300k+ if taken care of and the auto trans on the V8 is a good one.

 

[shadowless127]

buy it and rebuild or replace the motor. By me you can get a 5L with ~100K miles for like $450. Hell, while it's out you can even spend a couple hundred extra bucks and toss in a cam, intake spacer, and some other goodies.

 

[1992fordgreen]

If you think you can knock the project out I;'d get it

 

[99fordexplorereb]

yea i can do the work myself, i was just hopping the oil pump wasnt pumping the oil and cause of that the engine wasntg gettin oil and knocking cause of it, its not leaking anything

 

[Turdle]

a bad exhaust leak, which is common, will make a knocking noise.

 

[shadowless127]

a bad exhaust leak, which is common, will make a knocking noise.

That's more of a ticking sound; both annoying as hell though.

 

[koda2000]

That's more of a ticking sound; both annoying as hell though.

i've gotta agree with you there. an exhaust leak sounds awful, but if doesn't sound like a rod knock. they are both annoying, but only one is terminal.

if the rest of the truck is in good shape i'd snap it up for $500 (i'd offer $400 though).

 

[Turdle]

True, but going by his description of knock and scrape it could be an exhaust leak at the head.

Does oil pressure come up when it starts or does the gauge stay down.

 

[Alaskakid87]

a bad exhaust leak, which is common, will make a knocking noise.

I have a 1996 5.0 awd with a knocking as well but mine has an exhaust leak through the header area but it also runs a little rough at idle oil pressure is good and clean oil at that so how do i figure out if its actually the exhaust leak and not roller that has gone bad and scarring my cam? any ideas please if any I found a replacement 5.0 with 100k up here in a wrecking yard for 800 but dont wanna spend it if I dont have to

 

[shucker1]

Remove the oil filter if it has been on there for a while and cut it open.

If the inside of the filter is full of metal "Glitter" this would be a sign of a major engine internal part failure.

If it has a new filter run the engine for about 10-15 min to catch anything floating around in the oil.

 

[Alaskakid87]

Remove the oil filter if it has been on there for a while and cut it open.

If the inside of the filter is full of metal "Glitter" this would be a sign of a major engine internal part failure.

If it has a new filter run the engine for about 10-15 min to catch anything floating around in the oil.

I actually did that a few months back and no metal shavings were found at all. The oil was a little dark but after doing the oil change it is still clean and not metal shavings which leads me to believe it is a really bad exhaust leak but just not sure. My dad is a part time mechanic and seems to thinks its internal as well but knowing that explorers have an issue with the headers maybe it is just exhaust

 

[shucker1]

How about a compression check?

Piston with detonation damage would show up there as low compression on the bad cylinder.

That could cause a knock too.

 

[Alaskakid87]

How about a compression check?

Piston with detonation damage would show up there as low compression on the bad cylinder.

That could cause a knock too.

My dad and I will try and do the compression test and hopefully narrow down the search for my knocking... All in all I just really hope it just needs new headers. But the way my luck works it will need a new engine or rebuild