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I was looking at the Toyota two stage thermostat, seems a bit pricey. So I did some research and Mazda used a two stage thermostat on some of their engines including the 94 -97 Miata. As it turns out there is a more affordable source for their thermostat. It is the Murray 41492, I bought one at O'reillys for less than $10. I like the design of it, particularly the small stage. I might be near the upper limits using it on my 22R. I'm planning on drilling a 1/16" hole, that should help the overall function a little. What do you think, is this going to work ok. http://www.ebay.com/itm/like/201158426814?lpid=82 It is rated at 192 F just like the Toyota one. I'm having the very random and annoying shifting out of overdrive issue. I'm hoping this will help with that. Currently using a 180 F superstat.
Over the years I've used a lot of different brands of thermostats in my Chevy's. Once Robert Shaw quit producing the good ones the search was on. After going through a lot of aftermarket junk I finally settled on Stant SuperStats. As you know those are simple single stage thermostats but are decent quality.
I've read so much about the 22r engines loosing head gaskets I don't think taking the chance is worth it. So much so that even though my eyes popped out at the price of the factory dual stage unit I went ahead and purchased it anyway.
My engines thermostat housing bolts are so tight that I'm pretty sure the threads will be damaged when I back the bolts out. For now it's just sitting waiting for me to install it.
I decided to install it as is without drilling any holes. I put some anti seize compound on the bolt threads when I installed the 180 F superstat, so the bolts came out easy. The old rubber gasket was the same as the new one from O'reillys: PN mcs 2278... no need for a paper one. I noticed the action on the temperature gauge is a lot smoother now with the Mazda stat. I'm staying below the half way point on the gauge. I'm sure the stat is going to work very well in the cooler weather, I'm not so sure about 100 degree days in the summer time. I see the Mazda stat is listed for a Kia Sportage that has a 2.0 DOHC engine that puts out 130 HP. Also for a 89 Mazda 323 1.6 Turbo that has an output of almost 150 HP and 150 ft of torque.
Last edited by chuckross1957; 11-21-2014 at 11:26 AM.
I put some anti seize compound on the bolt threads when I installed the 180 F superstat, so the bolts came out easy.
I might try to install studs in place of the bolts so that all I'll have to do is remove two nuts to get the thermostat housing off. That should stop the lost thread problem unless someone torques them down really tight.
I think by using the rubber sleeve gasket, it isn't necessary to tighten the bolts really tight. The rubber compresses to form a good seal unlike a paper gasket which probably should be torqued down more.
I might try to install studs in place of the bolts...
Excellent Idea!
I'm on the O.E.M. side. We very rarely replace T-Stats, and I plan to keep my truck for life so $/year cost is very reasonable, considering the added reliability. I currently have OEM with jiggle vlave removed (equivalent to drilling). However, it let's engine run cold longer; I think that affects gas mileage. I also plan to replace it with Toyota 2-stage.
I have the 2 stage OEM thermostat. My cluster temp gauge used to sit perfectly horizontal, now it is ever so slightly pointed downward. Peace of mind.
Yea mine sits at about 1/4 of the sweep, 1/3 at most. I think someone installed a 180 thermostat. I just wonder if it's costing me some mpg's since its an FI engine.
Yep I actually ordered it from LCE, too. It was part of the round 1 tuneup when I first got my runner.
Considering I've been running lean this whole time without knowing it due to IAT sensor heat soak, it probably singlehandedly saved my engine from pinging.
I might try to install studs in place of the bolts so that all I'll have to do is remove two nuts to get the thermostat housing off. That should stop the lost thread problem unless someone torques them down really tight.
I realized that using anti-seize compound on these bolts is probably not such a good idea since the bolt holes go in to the coolant. It might be better use a sealant like teflon paste or pipe dope. I've used pipe dope on fan switches and it does a good job of preventing leaks. In this situation using studs instead of bolts sounds like a good idea. There might be an exhaust manifold stud that is used on another vehicle that has the right threads to fit.
You might be able to get the studs from Fastenal. They sell nuts and bolts to companies that build things and do machine maintenance. The problem with them is I believe you have to purchase a set amount like 25-50 though. My town has a place that will sell you bolts by the piece and I was going to hit them up. Hopefully they haven't stopped doing that or went out of business.
I've seen a few small block Chevy's with aluminum manifolds that had stuck thermostat housing bolts too. I consider it mostly an installation error. On the Chevy's I ended up using the newer housings that used the O-ring, anti seize on the studs and I'd snug them down with a 1/4 drive ratchet. Never had a single problem that way, leaks or otherwise.
Now that I recall I actually stopped using the studs and started using an ARP bolt kit #430-7402 that uses bolts with a reduced head. The bolts resemble Holley float bowl bolts. I hated the looks of the studs and with the size of the nuts the temptation to overtorque was still there. The ARP kit not only looked better but it removed that temptation because of the smaller bolt heads. That was a win win situation.
(The factory torque on the 22re housing is only 19 N-m or 14 ft-lbf but most people aren't going to look that specification up and just tighten away with their 3/8 ratchet overshooting the spec pretty easily)
11-20-2014, 07:21 PM
Thanks!
