How to prolong knocking motor

[scott_williams2]

95 k1500 350 tbi. So a week ago I started hearing a knocking noise at startup and during driving and my pressure gauge reads 20 psi when warm. It is best heard at idle. Took it to my mechanic and sure enough it's the dreaded knock aat 180k miles. My question is what can I do to prolong my engine a little more until I can afford a new one? Do the oil additives really work or are they a waste? should I run thicker oil? I currently run mobil 1 5w30

 

[DerekTheGreat]

Is it using oil by any chance?

My original engine made it to 225k before it was yanked, and due to a burnt valve. Made 15psi according to the factory gage at idle hot.

I'd try 5w-40 Valvoline SynPower with Motorcote, that shizz does indeed work. My lawn mower is knocking a bit under load but I don't hear it any more with that stuff in the crankcase. After watching Project Farm's video on Motorcote I'm sold on it, I run that in all my cars now.

 

[JackE]

I use RESTORE. You can get it from walmart. Its in a silver metal can. I put that in my 454 when it had the bad crank knock. I got a year out of it before I pulled it for the rebuild. Don't go with a thicker oil, it will actually do more harm than good. The passages on the Vortec engines are too small for too thick of oil.

Stock recommended oil weight in your flavor of synthetic and a can of RESTORE with each oil change, that's my advice.

 

[Supercharged111]

Cross your fingers and hold your mouth just right.

 

[kennythewelder]

There is no sure fire treatment for this. Additives may help, or may not. If you have a knock from the lower section of the engine, its like the mechanic said, a bad bearing. The more the engine runs, the more it will ware, and eventually fail. This will ether cause the engine to seize up, or just brake. If its a rod bearing, it can come through the block , oil pan, or both. If your going to just replace the engine anyway, then drive it until it comes apart. If your going to rebuild the engine, then you need to quit driving it ASAP. Your choices are huge when it comes to a crate engine as are the price ranges. Just a stock OE engine is not that expensive. The more HP you want, the more it will cost you.

 

[mistaake]

Switch to something thicker like 10w-40 or 15w-40 and if that doesn't quiet it down it's time for a new engine. I wouldn't waste your money on oil additives.

 

[letitsnow]

It may have been purely a coincidence, but I had the idea to switch my vortec 350 to 5w40 T6 because that is what I used in my dirt bike and I didn't want a bunch of different weight oils in the garage. The next camping trip, I got the terminal rod knock. The motor had 217,000+ miles on it, so it may have been coming anyways. Or maybe it was in really good shape and I starved it for oil by running high load/high rpms with oil that was too thick? Hard to say.

 

[mistaake]

It may have been purely a coincidence, but I had the idea to switch my vortec 350 to 5w40 T6 because that is what I used in my dirt bike and I didn't want a bunch of different weight oils in the garage. The next camping trip, I got the terminal rod knock. The motor had 217,000+ miles on it, so it may have been coming anyways. Or maybe it was in really good shape and I starved it for oil by running high load/high rpms with oil that was too thick? Hard to say.

I've put a lot of research into oil, though I'm no expert, so take from this what you will. There are many, many Vortec SBCs in SUVs, trucks, boats, and more happily running a variety of 40-weight oils with lots of hours or miles on them and no issues. The worst case scenario about switching from a 30-weight oil to a 40-weight is perhaps 0.1MPG worse and that's it. Your engine most likely had some other underlying issue due to high mileage and the recent oil change was a coincidence.

 

[92GMCK2500]

Scott - keep enjoying that truck man! If you intend on replacing the engine eventually just run it into the ground until it doesn't work anymore. Mine's got 275kms on it and probably been knocking for a good 100kms or more, and it still keeps truck'n! Camping, snow, mountains, forestry roads, highway, you name it, these engines are work horses! Just be accepting of the fact that it could go any day haha.

 

[Supercharged111]

Switch to something thicker like 10w-40 or 15w-40 and if that doesn't quiet it down it's time for a new engine. I wouldn't waste your money on oil additives.

Terrible advice.