Thermostat Replace?

I got the thermostat out with ease after removing the engine mount and alternator. Didn't touch the AC compressor. Of course getting the alternator out is a massive pain.

Why not consult the factory shop manual?  It is available as a free download with a little bit of searching on spyderchat.  It is also in the downloads section of Facebook Spyder group

Are you replacing the thermostat as preventive or is it stuck?  If its working I would leave it alone.   

Thermostats from this generation of cars last a very long time.  Statistically a new one can just as easily fail in a shorter period of time.

 The Thermostat in my car as well as many of the Spyders I have seen with the original engine never had the thermostat fail them but it is not unheard of as a few experienced failure but its rare.  

  This is the same with the water pump in modern cars as many have the original outlasting the engine hundreds of thousands of miles but you will find examples of some that had these components go at 60k miles and its most likely luck rather than certainty.   

 BMWs are very different as their stupid electric water pumps go out  around the 60-80k mark without fail. Stupid design to show off technology to shave off a tenth of a mile in efficiency.  Takes forever to get the cabin warm. 

@dev Yes, I know it is probably overkill, there was no problem and likely would not have been. I lost a water pump on the outskirts of Death Valley many years ago. Ever since then if I have a used car, as soon as I find out where the water pump is, I replace it. Yes, different car but I still remember.

Posted by: @dblotii

Why not consult the factory shop manual?  It is available as a free download with a little bit of searching on spyderchat.  It is also in the downloads section of Facebook Spyder group

I have one. In fact, two. I always prefer to hear from someone whose opinion I value.

I don't follow the "if it works, leave it alone." Because later it won't work. Someone told me not to get a rear main seal for my car because if it isn't leaking, leave it alone or I'd make it worse. Well when I removed the transmission, it was just starting to seep. Preventative maintenance is key. Use an OEM thermostat, replace it, feel comfortable for another 15 years.

One part of this that I do not like is that I also replaced the OEM belt with an OEM belt from Toyota. I understand rebranding and that Toyota does not necessarily make their "own" parts. What I did not quite understand is that the belt had "Toyota 99366-J1690" printed on it but also had "Mitsubishi 6PK1690". Why?

Mitsubishi makes many parts for Japanese vehicles that are used in a wide range of applications. It’s not uncommon to find competing companies take up the slack for being suppliers of the same part. 
Preventive maintenance is important  but if we were to replace everything that could go wrong before its time it is not particularly wise and expensive. I have seen some try to replace parts and end up creating a problem in the process with adjacent structures with stripped bolts and leaking seals because they don’t follow detail procedure or the tolerances are out of spec.  It really depends on the high likelihood of the part failing for that particular car and addressing it early or with a better part like the lift bolts on a 2ZZ.  The service alone to avoid a particular problem can be the impetus of a self fulfilling prophecy.  

If it’s a Ferrari that’s a different situation where seals don’t last and a early costly major service is required. 

If you follow the Toyota manual for maintenance, inspection, replacement of components based on mileage or age it’s more than enough and there are many that completely neglect needed service and still go the distance because these engines last a long time and are forgiving. The engineers have mostly figured this out along with their bulletins. 

This is not the same for other car makes unfortunately and with something like a BMW you do need to keep on top of everything well before the service interval like the main bearings on the M5.  

@dev Point well taken. If this were a Ferrari, I would not do preventative maintenance. I would sell it and buy a Spyder.

I have a friend that has an old Ferrari and it’s a major money pit. you start working on it for one thing and you end up having to fix 10 other things that you messed up along the way. Wonderful car to drive but a terrible car to own. Our Spyders sit at a point in time where we have the most modern reliability in components like timing chains instead of belt service but just before  the era of complexity with too many body control modules and all sorts of glitches. 

I have an acquaintance (from car show circuit where we both show our cars) who has a Ferrari and he told me that Ferrari required maintenance is once every 3 years (which he stretches to once very 5 years since he only shows the car -- not a daily driver) and that maintenance starts at $8,000.  When I first met him several years ago, he had just had the factory maintenance done and by the time they fixed the things that needed to be fixed (above the regular maintenance) the final tally on the bill was $12,000!   I was fairly new to Spyder-land when I first met Doug and thought to my self, geez, I only paid a couple of thousand dollars more (than his maintenance bill) to purchase my MR2 Spyder!  Regular factory maintenance is around $450 for the Toyota! 

A couple of years ago, he decided to have the leather redone in the cockpit and reported that he got an excellent deal from a vendor in the San Francisco area and the final tally on that bill was $19,000.

Doug is a great guy and he has a beautiful car -- and he certainly enjoys ownership (stewardship) of his vehicle.  He is playing at a completely different level than I will ever be able to play.  We both enjoy our cars and on more than one occasion (our cars are in the same competing class) we have both taken 2nd place (on different years) at the car show we share in competing.  I am grateful that given those parameters, I can enjoy competing with my humble little Toyota MR2 Spyder.  Its fun and quite satisfying that I can compete even with the "big boys".  🙂    

I just want to illustrate with an example of how things can go wrong with trying to be preventive or in this case an assumption that something needs to be replaced.  

https://www.mr2roc.org/forum/index.php?topic=70109.0

 The steering joint is often complained about because it has a lot of surface rust and people assume the joint will go bad. The joint is very well made and only looks ugly. Mine has looked rusted for many years and I when the car was purchased in 2004 it had surface rust on it.  

  Im not saying not to be preventative but it should be measured based on the likely hood of the part failing and if it is indeed a worn part not based on how it looks or that its something that is done on another vehicle.  

Im not above this as I ruined a perfectly good camshaft by improperly trying to solve an after fire issue by replacing the cam sensor which nicked the timing pick up. It turned out to be worn ignition coils.  My mistake was a nightmare that resulted in having to replace the intake cam which was not easy.