I have a check engine light that comes and goes and since a local mechanic advertised free diagnosis, I went. I had previously had them do a power transmission flush without incident.
So he tells me I need a new thermostat according to the diagnostic tool. OK...but I'm skeptical since the car's temps are always constant..meaning after a little warm up of 5-10 minutes, the temp gauge shows the needle right in the middle where it always goes since new. Does this sound right that I need a new thermostat?

By the way, this is a shout out thank you to UseYourNoggin who I believe just saved me a few hundred $$ (what the mechanic wanted to replace it) with his fix of passenger side windows that won't go up via drivers side switch..you the man and can't wait to get home to fix this!! It just occurred to me that the mechanic may know how to reprogram, but would claim he replaced with new switch. One would think he would know this as they are a Japanese only auto repair shop.
Almost forgot that when I picked up my car from this same mechanic, it ran very rough. I drove back and asked what the problems was a he said I needed to drive it for a few days to let the computer reset. That made no sense and the next day I popped the hood and after a minute of looking around the engine, I found a small hose that connects to the air cleaner was off! It was a vaccume hose and after putting it back on, it runs perfectly. Why would he remove?? And why would he not notice it off? Something tells me this guy is desperate for work and is a scammer. Your thoughts please.

 

if your car temperature is as you are used to see it, get away from that shop and get the codes from another place. to be able to help you a little better, we need a trouble code. and no, i dont think you need a new thermostat.

 

Thanks, glad to help. Like Juanky says without the code our suggestions would be just as bad as that mechanic. However, if the car has not had the coolant flushed or filled yet, now would be the time. Some times goop gets on the coolant sensor throwing weird stuff--flush & fill will help.

The mechanic would have made a fair bit doing the power window trick!

 

Thanks guys! And yes, I will get the car in for a flush and fill of coolant of which I did at 100,000 and now 180,000 miles. Also would it make good sense to have the brake lines flushed and the power steering fluid changed too? These have never been done. Amazing car that has cost peanuts for all these miles (just oil changes and air filters..engine and cabin) and still runs like a champ.

 

definitely overdue

 

Yes! I owe this car more TLC for certain.

 

if the code is a P0126-insufficient coolant temp then you likey do need a thermostat. It usually means the thermostat is opening too soon and not allowing to coolant temp to come up to its target range. It is a common issue on your vehicle.

A couple things to rule out however would be the ECT for the PCM and the wiring.

There is a separate temp sensor that is strictly for your temp guage.

 

I had the same experience with my 206 Mazda 6. I too, doubted the diagnosis, as my temp. gauge was perfect in it's indication. The dealer wanted an arm and leg to replace it, so did it myself. Took over an hour. Had to remove the power steering pump to get to the thermostat. don't disconnect the lines, just move it out of the way. You'll have to remove the right front wheel and inner fender splash guard to access the serpentine belt tensioner. At any rate, after living with that damn check engine light coming on at various times, I can say the thermostat completely fixed the problem, and that's been over a year ago.

 

Thanks much for this info!

 

Thanks very much for this info..appreciated! Since I'm not very wrench handy, any idea what a shop would charge?