87 2.8 Orginal owner oil changed every 3,000 to 5,000 miles. The car has 148,000 miles on it. Car was surging at idle. Pulled codes, bad MAS and relay and TPS. Replaced the parts on the car. It was running fine, the next day I started the car and now i have a bad rattle coming from the bottom end. It does not rattle at idle car runs smooth, but when i rev it up thats when you can really hear it. Sounds like it is coming from the oil pan. Do I need a rebuild?

 

First thing I'd do is remove the drive belt & test it for the noise.
Is it an automatic? Sometimes a cracked flexplate will make a rattle noise.
You can remove the oil pan & wiggle the rods, if they move then you most likely have worn bearings. Thats the time to pull it & have it rebuilt.

 

i worked on a 2.8 once that sounded like the bottom end was shot. it had metal in the oil, but wasnt overheating. turned out the timing chain stretched. it had an aluminum block in between the chain bolted to the block, if i remember. the chain was slapping that part & making a rod-knock sound. a mechanics stethascope or a long screwdriver held to the ear should help you isolate the noise. with those miles, its possible the chain is worn. best of luck.

 

If it is a spun rod bearing I bet it's rod bearing #4 that spun. Happened to me twice already on the 2.8 I had in my fiero.

 

take the belt off liek mentioned and se eif it stil does it, also put premium gas in it and try again. detonation/pinging can also sound like a knock in the bottom end.

my dodge intrepid does this.if i fill the car with the cheap stuff 85 octane it will ping like hell and it does sound like a knock, put mid grade/ 88 octane in it and it goes away

 

I will remove the belt and test it. What is this testing? I did put 5 gallons of low octane gas in it. Should I drive the gas out before adding the higher octane gas?

 

Any updates on this? I am having the exact same problem. But mine is still very obvious at idle, and at 1/4 throttle, all you hear is knocking over the engine. Sounds like the bottom end, drivers side, and you can hear it most prominently outside the car, right behind the drivers side front tire. Started happening after trying to do the timing on it, then sitting for a couple months waiting on a new transmission.

 

like stated above I would check the oilpan and timing chain and with those off check the rods and crank for wiggle... a rebuild would be beneficial to u with those miles

 

Timing chain was streched and hitting the motor. Replaced it now it is fine.

 

good deal. it seems to be a problem, with the chain stretching and slapping that aluminum block. sounds just like a rod knock but no over-heating issues. glad it was a cheap fix for ya.