Rod Bearing??? 97 OBW A/T

[Bradsit]

Hey all,

I have a 97 OBW A/T... I've already been through the dreaded head gasket experience with this engine, and now I have a newly developing problem. After I got the head gasket job done I started noticing a rattle in my engine. Typically at start up it rattles for about 2-3 seconds and the RPMs jump up to about 3k, then it drops to a normal idle and sounds fine. Also, when I'm driving on the highway I will accelerate and upon releasing my foot from the pedal I will hear a quick 1-2 second rattle just like when I start it. I have also been burning oil at a rather slow rate (I am assuming it's burning as there is no sign of leaking anywhere) this says to me that my oil temp is way too high. Does this sound like a rod bearing issue to anyone? If so, is this problem fixable, or am I screwed? I would like to fix it ASAP if this is a possibility to avoid my engine seizing or completely failing. PLEASE HELP ME!!!

[a97obw]

The old aircooled VW rod bearing detection trick was to hold the throttle at about 3k RPM for about 30 seconds to a minute, then close the throttle abruptly and listen for the (rattle) snake. You'd have to do this with the throttle linkage under the hood and not merely with the gas pedal. Have you tried that?

[Bradsit]

The old aircooled VW rod bearing detection trick was to hold the throttle at about 3k RPM for about 30 seconds to a minute, then close the throttle abruptly and listen for the (rattle) snake. You'd have to do this with the throttle linkage under the hood and not merely with the gas pedal. Have you tried that?

 

I have held the throttle linkage and listened...and I do hear the sound. It's like a metallic rattle on the left side of the block, right after I let up on the throttle.

[nipper]

another trick, is to remove the spark plug wires one at a time while the car is running, and see if the noise changes pitch. If it does its a connecting rod bearing.

 

 

You say you replaced your headgaskets, how hot did the engine get before you changed them?

 

nipper

[Bradsit]

another trick, is to remove the spark plug wires one at a time while the car is running, and see if the noise changes pitch. If it does its a connecting rod bearing.

 

 

You say you replaced your headgaskets, how hot did the engine get before you changed them?

 

nipper

 

The car overheated multiple times before I was able to actually change them. However, I would pull over any time it started getting really hot, to try and avoid any permanant damage such as cracking the block. Since the head gasket change the car has performed relatively fine...except for the rattle noise which has continually gotten worse over the past few weeks.

[nipper]

was just wondering if the oil got baked, it sounds like it might has .. can i take a wild guess, do you think its the rear cylinder on the passenger side?

 

 

 

nipper

[Commuter]

was just wondering if the oil got baked, it sounds like it might has .. can i take a wild guess, do you think its the rear cylinder on the passenger side?

nipper

nipper, what is the connection? My rod bearing failed on no 3, that cylinder exactly.

 

Bradsit, when you say left side, do you mean when facing the engine? That is, passenger side?

 

Commuter

[nipper]

i'm not sure. Without seeing a oil journal diagram, im guessing thats the last connecting rod to get oil. i am starting to suspect that when a head gasket goes, and the enigine gets repeatedly heated, or one really good overheating, thats the hot spot in the engine. That when you do a head gasket, or had an overheating , it is important that you get an oil change too, no matter how soon the headgasket went or the car overheated since the last oilchange. Oil gets too hot, it will thin out to the point where the thin layer of oil that cushions the bearing, is no longer doing that, then the bearing starts getting hammered. It doesnt take much to destroy a bearing Engine oil i think is not happy when it gets over 210-220 degrees. On aluminum engines, it can heat up pretty fast in an overheat condition.

It seems like this is good added advice.

There hasnt been many of these, but i have also seen this on the list for putting subaru engines in VW's, only there they use a much smaller oil pan, and basically make the condition themselves. I told them you never want to reduce oil capacity, but you want to increase it.

 

nipper

[Bradsit]

nipper,

It sounds like you have a good case of logic going here. Yes, it is the rear passenger side cylinder that I suspect is creating the noise. I'm guessing that the only way to really find out if this is the case, is to pull the engine. If it does end up being a rod bearing, what are my possibilities of fixing it. Does it depend on damages suffered thus far, or are engines typically done at this point? Is this an extensive fix...if it is possible to fix? Thanks for the responses.

[frag]

Since you first described your engine's condition as a "rattle", since the n° 3 cylinder (rear passenger side) is very close to the Y pipe's heat shield, and since it's a good thing to eliminate all cheaper possibilities first, are you sure you're not hearing a heat shield rattling? My heat shields rattle when I let off the gas.

I know the sound is not the same as a connecting rod knock but, for my part, i'm not sure I would always be able to make the difference.

Just in case.