Can coolant leak cause misfire?!

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Jan 16, 2010 | 03:31 PM

Stinkpickle

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From: Deptford, NJ

Can coolant leak cause misfire?!

Could coolant in the engine oil cause a misfire? I recently noticed I was slowly losing coolant. Changed out the aux. coolant pump but no dice. Then I checked the oil. It was bubbly at the end of the dipstick. Crap...coolant in the oil. I highly suspect my oil cooler is at fault causing the mixture. More recently, I've been experienceing a misfire under wot. Engine is smooth at idle and casual driving. A few days ago got a flashing cel at wot that stayed solid. Got a random/multiple misfire code and a cylinder 1 misfire code. Changed out the coil pack for that cylinder and although the misfire is less noticeable, it's still there accompanied by real spikey boost and the occasional flashing cel. Changing the plugs and doing a boost leak test tomorrow to be safe. But back to my question...can coolant in the engine oil be the cause of the misfire? Someone out there please help! Thanks.

BTW, what plugs do you Stage 3 guys recommend?

Jan 16, 2010 | 10:35 PM

diabolical1

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i suppose if you lost enough coolant to get the head temperature way up, it could cause preignition that may trigger a misfire CEL. it's a stretch, but i doubt that's what's happening in your case. the plug could simply be fouled from when it was doing it before you changed the coil.

Jan 17, 2010 | 05:58 AM

donromani

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haha - Stink, you have gone through every possibility except for the usual culprits. You're like friggin Dr. House over here with this misfire. Next you'll be asking if Lupus could be causing it!

Have you tried moving the coilpack yet? IIRC you did a boost leak test, right?

As for plugs, many people use the side-fire types on stage3. These are specifically designed for high boost applications so stick with the OEM plugs until you go stage3 yourself. Stay away from iridium. Bosch platinums are what you want.

Last edited by donromani; Jan 17, 2010 at 06:01 AM.

Jan 17, 2010 | 07:46 AM

complacentsee

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Lupus.

Jan 17, 2010 | 08:35 AM

Stinkpickle

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From: Deptford, NJ

Quote:

Originally Posted by donromani

haha - Stink, you have gone through every possibility except for the usual culprits. You're like friggin Dr. House over here with this misfire. Next you'll be asking if Lupus could be causing it!

LOL donromani...I was actually gonna ask if it was swine flu that was causing the misfire. I'm sure it's one of the more common causes (plugs, boost leak, etc.) but with my luck I always try to prepare for worst case scenario!

Jan 19, 2010 | 05:55 PM

Stinkpickle

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From: Deptford, NJ

Turns out the misfire was just a simple case of bad plugs and not Krohn's disease like I first thought. Brand new set of NGK BKR7Es gapped at .025and she's purring like a kitten again.

Jan 19, 2010 | 06:21 PM

donromani

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If I've learned anything from House it's that if the patient seems to be getting better that's when the **** is about to hit the fan...If I were you I'd put her on an IV drip and treat for Sarcoidosis just to be sure.