This is the water pump that just came out of my '93 S-Special. There were no warning noises and no warning leaks. The car had done 3 weeks in my ownership with the temp gauge at that happy 11.30 position we all like. The only issue I had with the cooling system was that the heater only blew out lukewarm air.
The car went to my local garage on the Tuesday to have them fix the heater. They said they’d fixed it by bleeding the cooling system, and charged me for it, and I paid. Ten minutes after I set off Wednesday morning I discovered they hadn’t fixed it, so put my gloves on, zipped up my jacket, put the roof back up, and carried on, 2.5 hours into the (necessary trip), the heater suddenly blew out a puff of fully hot air and a whiff of coolant. The temp gauge was off the top of the scale. I switched off within a second and pulled over. When it had cooled down I had a look under the bonnet, expecting to see coolant everywhere, including on the hard shoulder. Nothing!
Long story short, I ended up at an MX5 specialist only 2 minutes from the motorway. They could see or hear nothing wrong. Then they asked about recent work. I told them about the heater still not working properly. They checked the hoses with the engine running. NO pressure. At which point they said it can only be the water pump (interesting given that the dealer who sold it 3 weeks earlier told me it was well maintained).
As can be seen by the complete lack of vanes on the impeller, the pump had not been pumping for many years. The heater hadn’t been pushing out hot air because no hot water was reaching it, due to the complete lack of pressure. So how come the temp gauge was only at 11.30, and the engine hadn’t overheated before? THERMO-SYPHONING! This is where hot water rises and cool water drops, creating some circulation, but no pressure.
So please, if you don’t know when your WP and TB were done get them done to avoid the head gasket mine needs, plus the time off road, hotel bills, public transport to get home and back, etc.
I am, of course, expecting the dealer and my local garage, between them to sort out the costs, as the dealer has to give me a statutory warranty, even though he’s pretending to be just a member of the public, and there is no way that “pump” could have made the heater hot, so my (now ex) local garage were, at best, misguided as to what is hot in an NA heater, although they got my other NA’s heater fully hot two weeks earlier, so they’d had practice!
)engines used in any Miata. This would be with, or without a thermostat installed. If you talked about thermo syphon cooling with your “6 out of 6 mechanics”, and they all agreed with your theory, then they are not mechanics I’d ever want to bring my car to, not any of them, as they have no clue and are just nodding their heads to get you off the phone, or out of their offices, they would never testify to such nonsense under oath. I know, tough to read, but still the truth, whether you want to acknowledge it as such or not. My posts are based on hands on knowledge, as other can attest to, I work on 75% of what I own, and have well over 1,000,000 miles (documented) of road and track use.Did the water pump work for a while, if you drove the car for more than 5-10 minutes, I’m going to say yes, it would have to, or the car would have over heated (forget thermo syphon cooling, drop it from your vocabulary) . Is it sad you were taken advantage of by a dealer, after you spent a good portion of your life working for one and knew what to ask, both verbally and in writing, absolutely. Is it a bad thing to have the reality of it being brought up here, no, why, simply, you started this thread requesting assistance or opinions on this situation. Again, there are times where we all need to have our hand held (so to speak), and to be properly guided so that we can successfully move on from our mistakes. Some will try to do so gently, in a round about way, some (like myself) will tell it like it is, maybe more matter of fact than you want to hear or read, but the goal of getting to the bottom of the problem, and educating you (and others than may read this thread years down the road) at the same time, so that such an occurrence does not happen again.