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Anyone else have "oil farting" (massive smoke cloud) issues in their 3cyl Geo Metro?

I was wondering if anyone else here has a Geo Metro and has experienced gigantic smoke clouds out the tailpipe when driving under load, especially freeway speeds. I recently picked up one of these small economy cars and understand this is a common issue. I was getting it bad until I gave me engine a good flush with Marvel Mystery Oil and Seafoam. It appears to be solved now so I guess I either cleaned up some stuck rings that were causing excessive blowby or there was crud I cleaned out of the oil drainback holes in the head. It was puking oil through the PCV line back into the intake and I had just changed my PCV.

I am on a Geo Metro forum and this appears to be a common issue. The term commonly used is “oil farting”. If you have one of these cars and are experiencing this, you might try a good flush of the engine before considering junking the car or rebuilding/replacing the engine. I let some Marvel Mystery Oil soak in the cylinders overnight too.

Be ready to change the oil and filter after doing this flush as it will get REALLY dirty and nasty really quick. I drove the car maybe 20-30 miles with some MMO and half a can of Seafoam in the crankcase.


You might also clean out the PCV system, not just the valve…The vacuum port that the valve connect to tends to get plugged up disabling the system…The valve needs a strong, high-flow vacuum to work properly…Your problem is common to ALL ill-maintained engines, not just the one in a Metro…

Yeah, I cleaned the entire PCV system and it was filled with sludge. I had done this before the smoke blasting. The air cleaner housing is now dry (no more oil spitting) after the good engine flush I did on it. I think something was just gummed up and I cleaned it out. I am not sure what it was, but something was wrong as I took it out and drove it really hard and couldn’t get any more smoke blasts. I will be taking a decent trip in it today on the highway and see what happens after extended driving.

I am using a good filter and full synthetic oil. Compression numbers also range between 170 and 180 so not too bad. I didn’t test this before the flush and kinda wish I had as of now. I think I may have gotten lucky with this little car, otherwise I have another junk engine I will just rebuild if this one has too much wear.


Congratulations on your success and thank you for the info. It’s proof that sometimes additives DO work!

I am a big believer in some of these additives. I do not believe in leaving them in the oil for extended periods though as I want to get them and all the crud out of the engine ASAP. Many of these chemicals are pretty volatile and will leave the oil pretty quickly. I figure all the crud will just drop right back out somewhere else in the engine. The times I always hear about problems are where they are used for like 500 miles.

I also suck the same additives right through the intake to decarbon the cylinders.


You might consider dropping the oil pan and checking the oil pickup screen to make sure it’s not partly clogged with the crud you’ve loosened.

Good idea. I will likely do this as I had an old Ford 302 that had been neglected and I could see all sorts of crud on the pickup screen. I had the oil pan off earlier after doing a similar flush for a much shorter amount of time to reseal the leaking pan with RTV and the pickup screen looked pretty good. I am hoping that the crud mostly came out with the oil as I changed it when it was still hot. Either way, better safe than sorry and this is easy to do. These little cars are so simple and a breese to work on. I can easily pick up and carry a complete engine by myself. I am looking into a few more to fix up.