Water warping rotor? EGR question too...

[haseltonk]

I've never seen this before, but it seems like water is warping my rotors, specifically the LF. Since it's summer I ride my motorcycle most of the time, so the Metro doesn't get a lot of use. A couple weeks I hop in it after it hadn't been driven for about a week to discover that the rotors had warped fairly severly. At first I thought it might just be rust build up, but it never went away. It was still driveable, but the warping was definatley noticable. Up to this point there had been no warpage at all.

So I go to hop in it again today after it had been sitting for about 3 days and the rotor is so warped it is unsafe to drive. I would have replaced it by now but I have a speed sensor in a Probe that is making my life a living hell (anybody know about those) and I've been dealing with that instead. You basically have to use the e-brake to stop because there is such a modulation in the pedal it doesn't feel safe otherwise. I have always been under the impression that numerous, extreme heating & cooling sessions are what tends to warp rotors. I have had these rotors for probably 60-70k miles, so I'm not surprised that they need to be replaced...but it does surprise me that it was the lack of driving that appears to have caused it, rather than driving. Is there anything else that would give the same symptoms of a warped rotor - maybe I'm mis-diagnosing it?

While I'm at it I saw a post that a clogged EGR could burn your exhaust valves. About 35-40k miles ago my check engine light came on, code was for EGR...vacuum checked it, cleaned it and everything seemed fine but I kept getting the light (even after clearing it a couple times). I thought it was just an emissions thing so I kept driving with it...and still am. I'm guessing if it was clogged I would have burned something by now. How would I know if I burned a valve, and I'm guessing at this point there isn't anything more I can do to hurt it...so just keep driving until the inevitable...? What do you recommend? Thanks...

[Infinitrium]

Have you removed your front tires and reinstalled them recently? The 3 cylinder Geo's have tiny rotors, and if you overtighten the tires you can warp your rotors. If you've burned a valve you'll notice an uneven idle, and some shaking. Also, your exhaust note won't be consistent. Best way to tell if it's a valve is to do a compression test. The exhaust valve on the 3rd cylinder seems to be the one that always burns up. Basically, these cars run a lean mixture which burns very hot and the EGR dumps some exhaust gas into the combustion chambers to help cool the valves, and if the passages in the EGR valve and where the EGR valve bolts onto plug up with dirt, then your exhaust valves will start to burn up. If you don't mind getting a bit dirty, whenever you change your oil, remove the EGR valve and spray it with lots of carb cleaner. Spray some carb cleaner up into the EGR passages, let it soak then rod them out with an old metal coat hanger or something similiar.

[haseltonk]

No ther tires/wheels have not been off recently. It's been at least a few months. So if I already toasted a valve (which is hard to tell based on the symptoms you mentioned since it's had a semi-rough idle a little shake since I bought it at 36k miles.) can I make it any worse by continuing to drive it?

[Crvett69]

might also have tires going bad, if a cord seperates it can cause wheel shake too. or maybe you have some low ones. check all your tire pressures. rotor should not go bad from sitting but tire might

[haseltonk]

I'll check into that, but the problem only occurs under braking so I'm thinking it has to be rotor related. I have new pads/rotors so hopefully that will fix it...

[geozukigti]

The rotors are probably too thin, and are being crushed by the brake pads. Happens when they go out of tolerance, or all the heat over the years has destroyed the metal. Simple replacement should solve it. Also, I drove a metro with a toasted valve fo a year. It was just annoying, and the cat will get hot.

[Arnoldtheskier]

Just went through this.It was not actually the rotor warping..BUT..the "facing" on the rotor bulging out.Rotors used to be solid.I don't know when they started to introduce rotors that were "faced".Not sure if any of the aftermarket,replacements are faced.(A buddy got a shock recentlly when his fairly new Chrysler min-van needed brakes.Do it he said.They did.Under warranty.Brakes NOT coverred.New rotors.HUNH??..they are faced and are NOT turnable.)This happens(in your and my case) when they start rusting,rotting from the inside out.The facing loses contact with the body of the rotor in a spot..or two.Junk gets under it and WAHZOO!..At the VERY first..you swear the rotor is warped.The pads look ok and LOL..SO do the rotors..they appear to the eye straight enough to NOT do this.If you continue to drive it as I did.Why not? The pads and rotor appeared ok..Mine were NOT thin either!.Next stage is that a tiny ,tiny crack will appear in the rotor facing..and you will definitely hear a "click click" sound.Then a piece of this will simply come off..THEN you hear,FEEL..BANG BANG.New rotors or don't drive..When you pull the wheel again you will see a piece of the rotor facing gone.Sometimes you can pick it off with your fingernails.You may be surprised how thick it is!.

My first expericence with this was on a very well treated and maintained(ONLY dealer serviced) Chrysler mini van in 1993.The van was a 1991. less than 20,000 on it.Original pads,rotors.Developed a SUDDEN warped rotor symptom.We continued to drive it..pads(thickness),rotors looked ok.Not far mind you..pieces of the rotor facing cracked and came off.Even though this vehicle was under warranty AND had had a recent brake inspection..Chrysler simply refused to fix it..saying it needed brake pad replacement.They said that their brake inspection was fair..and it was not standard practice to remove the calipers and actually check the pad facing(it isn't).Even though the pads had plenty of life in them they had wrecked the rotors.