I have an S5 TII that was in storage for an indeterminate period. It appears to be a JDM motor, anyway the deal is it starts and runs quickly, i.e it's not flooded but it does idle rough and is down on power. I have a check box I built myself which does give codes when the various sensors are unplugged, it has no codes active when the engine is running and everything's plugged in.

So there's a real good chance this is due to the apex and side seals sticking. The motor does not overheat and holds great oil pressure, there are no oil or coolant leaks so I'd like to not tear it apart if I don't have to.

In the past I've used ATF and WD40 on so called 'hopeless' motors with reasonable success, just wondering if there's anything new out there?

 

I have had pretty good success just spraying a bit of wd40 in there through the leading spark plug hole and rotating by hand to spread the stuff out. ATF will tear stuff up after a while as described by AaronCake.

Put a bit in, rotate a bit more an rotate. Remove the comp and fuel pump fuze and just let it rotate with the starter, let it set for 15 minutes and repeat 2 more times. Reconnect everything and take it for a nice long drive and see if anything changes. If this does not fix it the seals may require a good "massage" through the exhaust port.

 

Interested to know if ArmyOfOne's solution worked or not for the OP, I have a car that will be coming out of sitting for a decent amount of time and may/may not run into the same problem although it's good to know a possible solution.

 

Regular old motor oil typically works very well for freeing stuck seals. It does dissolve carbon quite well if given enough time.

Removing An RX-7 From Storage, Dealing With Improper Storage

 

Agreed. Use engine oil. Don't ever use ATF. Not sure why ATF is still so popular and continues to get recommended left and right even though we know it can damage soft seals.

 

Did not know about the ATF issue, glad I asked here first! I used WD40 on a 12A, it worked pretty well but that was ~10 years ago and I'm sure that progress has marched onwards.

I checked for rust through the plug holes best as possible, didn't see any. I lubed it before starting, also ran it on premix just to be on the safe side. Which brings me to this question: if I suspect stuck seals, should I just liberally oil it through the plug holes and let it sit, or ?

I need to give it an 'Italian tuneup' also, but the car is not even faintly street legal and there's no place nearby to do that.

 

I have left WD40 in there for a couple of days, rotating it every once in a while. Regular motor oil will work as well but it does not have the penetrating properties of WD. So it may take longer.

 

What is OP?

 

Original poster

 

Another stupid question: how about the GM Top Engine Cleaner or its Mopar equivalent? The Mazda version is not readily available in my area.