Question

[Bertiespeed]

My buddy just picked up a 94 with 305 for dirt cheap being it has a slight bottom end knock it sounds like. Its only barely noticable in idle or park anything under 1000 rpm from underneath the truck. driving on and off gas its non exsitant ! any ideas if hes lookin at a rebuild or somthing simple ?. He just changed the oil today with castrol high milage oil and a fram filter after running some seafoam for about 100km in the old oil hoping it might dislodge some sludge or somthing but its still sounds the same .

 

[71 cuda man]

I'd get rid of that fram filter first of all,total junk.The inners are cardboard doesn't trap anything.Get some seafoam & add 1/2 can to oil,run engine bout 10 mins.Drain oil /filter.run old oil thru a paint filter & see if theres excessive metal.That should clean any junk out of engine

 

[Bertiespeed]

I told him not to get the fram but its was on sale i guess :/ he ran seafoam through it for a days worth of driving then we drained it and put new oil in no signs of metal but was black lol . Oil pressures good and runs great just slight low rpm bottom end knock in idle or park. Timing maybe ? oil starvation ?

Also I noticed when we were out yesterday when in gear and warm she idle's at about 250rpm

 

[towman]

check the flex plate, they crack around the bolts and will flex and sound just like a rod knock, will do it more in park and neutral because there is no load on them

 

[Bertiespeed]

check the flex plate, they crack around the bolts and will flex and sound just like a rod knock, will do it more in park and neutral because there is no load on them

Ok i think this is whats causing his noise and read that maybe the bolts are just loose being its very slight but im not a tranny guy . So im assuming the tranny needs to be pulled for this ?

 

[DRAGGIN95]

Could also be a sloppy loose timing chain.

 

[Swims350]

I ALWAYS see ppl talk trash on fram, well you know what??? I ran em for years, NEVER had a problem. I've had engines apart that we built and looked at them after using the frame filters, no dirt, no damage, no gummed up or gel filters nothing. Now I use the cheapest I can get usually a super tech or store brand. I never had an issue with one though not once.

Now on topic, had same thing happen to an 86 k10 305. When we pulled the motor out to put in a 350 we tore the 305 apart and found some bearings messed up and crank messed up. It was scored and scratched up, was supposed to have been rebuilt before we got it, but it was an 85 block in an 86 truck. and NO the fram filter didn't cause it. it was damaged before we got the truck and had a napa filter or something on it.

Ours did the same thing, only knocked in idle in park or whatever, and went away when you started to hit the gas.

 

[RHamill]

I'd get rid of that fram filter first of all,total junk.The inners are cardboard doesn't trap anything.Get some seafoam & add 1/2 can to oil,run engine bout 10 mins.Drain oil /filter.run old oil thru a paint filter & see if theres excessive metal.That should clean any junk out of engine

My truck has 218,000 and my moms truck (97 w/ 5.7) has 250,000. Both run fram filters and quakerstate high mileage 10w30. I guarentee you havent heard a better running 97 with a quarter million miles ever.

Dont run seafoam in your crank cases either.

 

[93Chevy_1500]

check the flex plate, they crack around the bolts and will flex and sound just like a rod knock, will do it more in park and neutral because there is no load on them

x2 mine was cracked to ****. because of a worn out tranny mount it broke my flywheel. Sounded just like a lower end knock. But when i went under it to see where it was coming from it sounded like the flywheel was going to explode. I didnt have to pull my trans. I pulled my inspection cover off and was able to pull the tranny back just enough to change the flywheel. 50$ fix and no more knocking sound. Couldn't hear it going down the road at all only at idle in park or neutral.

 

[Bertiespeed]

He told me today that the truck dosent like overdrive going up hills (no weight) and has to drop it in to 3rd or it "shifts funny or slips" He thinks lol now like i told him im not a tranny guy (i been very lucky and have never had a tranny problem with any vehicle ive ever owned) so i have no idea so this may be a dumb ass question but could this be part of this flexplate problem ?