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Hi all,

As the title says I'm dealing with a broken connecting rod. The rod broke the first time I drove more than 2-3 miles and at a speed higher than 30 mph since the head gasket was replaced.

The blown head gasket resulted in a warped head which had to be replaced. I know that mechanic needed to do some machining but I'm not exactly sure why.

Yesterday when I was going about 70 mph on the freeway I heard a knocking sound and white smoke started coming out of everywhere. I pulled over and had the car towed back to the shop. The previous repair was under warranty so I was thinking he must have screwed that up and would have to fix this one. The extent of the damage is BAD. There was a piece of engine block sitting on the tow truck bed when we got to the shop.

Anyway the mechanic claims the failure had nothing to do with his repair and that it is either due to wear and tear or oil starvation. I have a hard time believing this.

Is it possible that improper installation of the head gasket caused oil not to reach that cylinder? Could coolant have leaked into the cylinder and caused it? Also, I feel that if he machined something on the block that could make the compression chamber smaller and increase the force on the piston causing the quick failure.

This is just driving me crazy. less than two weeks after dishing out all that money the whole engine is toast. I wanted to replace the engine when the head gasket was blown (used engines could be found at about $1200 shipped) but the mechanic talked me out of it saying this was an easy repair for him.

I'm suppose to meet him this afternoon to discuss it. I want to go there prepared so he doesn't just BS me. Is there anything particular you guys think I should bring up?

Also, do you think I have a case if I file a complaint?

I have owned the car for 7 month. Bought it for $4300, clean title, perfect condition, no history, with a new timing belt and water pump. Only 90K miles on it...

EDIT: It's a 2004 Forenza by the way.
 

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Rods don't just break like that, and they don't break because of wear & tear, and in my opinion the BS has already started - for the mechanic to claim the second failure was not related to the first prior to a tear down and examination of the engine is not a good sign.

Having said that - under normal circumstances, replacing the head would/should not lead to a rod failure, and any machining needed would have been on the head, which you say was replaced, so no machining should have been required in your case.

Lack of lubrication is a distinct possibility, the cause of that lack of lubrication is what needs to be determined, and it may or may not be related to the replacement of the head, and no, incorrect installation of the head/gasket is not likely to be the cause of that lack of lubrication.

Oil flow is usually from the pump, through the filter to oil gallery which will feed the crankshaft main bearings and through drillings in the crank, the rod bearings - a feed from the oil gallery will go to the head to feed the cam bearings and valve train. If your failure is lube related, it will be a rod bearing that failed, and it would be extremely unusual for head gasket to affect that in any way.

Could coolant in the chamber have caused the failure - I believe it's possible - the engine hydro-locks and bends the rod, which then fails on the next revolution.

First question - which cylinder did the failure occur on?
Second question - what machining was required?
Third question - what condition are the piston & valves for the affected cylinder in?
Fourth question - were the oil & filter changed after the head replacement?

There are multiple possible causes for the a broken rod - sometimes the resulting carnage makes it hard to tell what the sequence of events was, other times it's pellucidly clear, but without a teardown and inspection, there is no way to know if the two failures are related or not.
 

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WOW this is quite unfortunate. I think this is the first case of broken rod I've heard of on this car. This is definitely not a normal wear item and they should never break on a stock motor if everything is operating properly. Hell, mine is turbocharged and was consistently making 260whp for YEARS and no connecting rods broke or even bent.

However as fordem says, it's going to be hard to nail down what caused this without a complete teardown and analysis of the motor.
 

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existence,

just jumped in here as a 2004 Forenza owner, 260whp on your Forenza without forged rods, that's amazing!!!

to the OP, my wife and her dad completely FUBAR'd her Forenza (now mine), by not properly screwing down the oil cap! needless to say, oil went everywhere on my wife's drive over a short distance, long story short, she warped the heads and everything was a loss, cheaper to replace the motor verse all the repair work. i found a motor/transmission combo on Ebay for $600, 5k on it, and did a motor swap. 70k later, all is good :)

i have to say, this car as the craziest maintenance schedule... i'm overdue for a head gasket and considering doing it myself. like others have mentioned, i can't see a head gasket causing a connecting rod failure, but i'm not a certified mechanic.

i wish you the best of luck!
 

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existence,

just jumped in here as a 2004 Forenza owner, 260whp on your Forenza without forged rods, that's amazing!!!

...

i have to say, this car as the craziest maintenance schedule... i'm overdue for a head gasket and considering doing it myself.
Thanks man! Ya I've never had any issues with the bottom end.

As for the headgasket - are you considering that as maintenance? Those are not SUPPOSED to be maintenance/wear items - the HG "should" last the life of the car. However for some reason on these cars the stock HG seems prone to failure for alot of people. However, if yours is still good don't change it just for the hell of it ... unless you plan on making some decent power :)
 

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I messed up my car parts terminology... I meant valve cover gasket, which is supposed to be replaced every 60k on the Forenza's. Being at the top, I think they cook/bake, and go bad pretty quickly, ie dry out! Anyway, I posted elsewhere here on that topic because mine is overdue and I just discovered my far right plug was coated in Fresh oil... just did an oil change yesterday, dammit!! Another thing to deal with, lol!


But this video may help some know what I'm even talking about, LOL!
 

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Interesting finding about the bolts being too long... Although I never really had the leaking valve cover gasket issue myself..
 

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This is the first time I'm hearing about a gasket with a replacement "schedule" - where I come from gaskets are never touched unless they leak, and usually they never leak unless you touch them.

There are exceptions, such as gaskets sealing access covers that need to be removed for service access - one example might be valve cover gaskets on vehicles that require valve lash adjustment (I'd like to believe the Forenza has hydraulic lifters and is therefore excluded) - these gaskets are usually made from a more resilient material to allow for reuse.

I also find it strange that leaving the oil cap off would cause the heads to warp - oil everywhere yes, warp? are you kidding me?
 

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I suppose the headgasket could leak enough coolant into the motor to hydrolock or nearly hydrolock it. At that point something has to give and it's usually the rod. When I was a tech at an Acura dealer I had a customer with a cold air intake run through a puddle, lock the motor, and get towed in. We made no promises but after pulling the plugs and blowing air through the cylinders we were able to get it running good again. A couple of weeks later it came back with a snapped rod. The initial lock up must have tweaked the rod just a few thousandths and once it's even a tiny bit bent it's just a matter of time until it breaks.
 
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