Has anyone ever hear of a vacuum modulator? I searched and have checked the FSM and I can't figure out what this is. I bought my son a 91 non-turbo (automatic, yes I know) bone stock with 62,000 miles. I have a 85 GSL. The 91 is suffering from the white smoke out the tailpipes syndrome. Searched "white smoke" and read all 120 posts. I've called around to discuss rebuilds as was told by one to check for water in the vacuum hose going to the vacuum modulator and do a coolant leak test as well. Any help will be most appreciated. First post here, but I read everything. You guys are sharp with the RX's so I thought you might be able to help. Thanks.

 

No such thing, not on an FC anyway.

 

That's what I thought. I'll call him again on Monday. A very reputable shop surely I misundestood. Supposedly another check before rebuild for coolant seals. Thanks for response.

 

The vacuum modulator is a component of the Automatic transmission and is bolted on to the transmission housing.It has a tube which comes out of the device and needs to be checked for fluid(transmission).Since it works on vacuum "only" air should be present in the tube and if any fluid is present then it has failed and needs to be replaced.They can be had at Mazdatrix for $85 for a 91(S5).Drain a quart of tranny fluid when replacing.When they go bad quirky things can go wrong and make an auto transmission unreliable.Hope this helps.

 

^ well damn. learn something new every day.

 

Satch, your the man, Buddy. Thanks so much for the information. I'll post results maybe it will help someone else. Thanks again.