I bought a near mint 1993 Subaru loyale the other week for 300.00 with a rod knocking. After taking to the people they said they were heading to town for a high school ball game and it started knocking. . When I got it home the two things that I noticed was it was low on coolant and the car has the factory 175-70-13 on the front and 185-80-13 on the back. Do you thing havning different size tires n the back could have caused it to start knocking

Different size tires on back will cause torque bind while in four wheel dive but it wont cause an engine knock. Low oil and over heating will cause the crank bearings to loose lubrication burning them up and make the knock.

Are you sure it's not a lifter tick? It can sound like a rod knock if you haven't heard one doing it before.

 

Drain the oil and check for metallic swirl in it. If it looks like metallic pain pen..... probably communist gnomes making weapons in there.

 

GD

If it is rod knock, it's easier and cheaper to replace the motor (six bolts vs. a sh*tload. Same for hours of labor.) than fix the rodknock.

 

If it is low on oil and overheated it could be pinging and/or lifter tick, too. Get a recording and put it up! Good price, will be under a grand for purchase price, new motor, timing belt kit, and full gasket kit AND a replacement motor if you have to go that far. Keep us updated.

I use a 3/8" poly supply tube that one would use for a water supply line for a lavatory sink and use it as a Stethoscope... listen at points around the engine.

It will help you pin point the various noise between ticks of lifters or a solid knock which could be a crank shaft bearing...