Hey guys, I have an '84 pickup that I am installing a 2.7L 3RZ into. I spend most of my time in the 84-85 forum, but this is a '98 Tacoma engine question...


The engine did not have a thermostat installed when I disassembled it. I know from past experience that the springs(reactive side) goes into the block, or towards the water pump. This is for the warm coolant to open the thermostat and get into the radiator to be cooled. But since the radiators are vertical flow, I would presume that the coolant would flow top to bottom, for gravity to assist coolant flow. So if the thermostat follows that reasoning, how does the thermostat work properly if the springs are towards the water pump, and cooler coolant continually passing over the thermostat, keeping it closed or partially closed?

Bottom line, which way does the coolant flow, and how is the thermostat placed in the housing?

Any help is greatly appreciated, thanks

 

Any help here?

 

That's why Toyota uses a 180* T-stat, because its on the return side. If it was on the hot side (top) it would be closer to 200*. My Taurus uses a 198* from the factory because its on the top going to the rad. Make sense?

 

BTW Marlin's forum has lots of help with that swap.
http://board.marlincrawler.com/

Big Mike's swap: http://board.marlincrawler.com/index...light=3rz+swap

 

I appreciate the response, goat. I have been over all the build threads many times over the last few months. I just never saw anyone talk about t-stat placement. It just didn't seem logical to me for the downstream, cooler fluid to pass over the t-stat. Which I would think would keep the coolant in the engine hotter, but judging by what you're saying, that's what Toyota is trying to accomplish. Just seemed bass-ackwards to me...

 

All the auto companies seem to run right to the border line of too hot IMHO. I run a 160* T-stat instead of 180* in my truck and a 180* instead of a 195* in my Taurus. I guess emissions are the reason.

 

Well, I will attempt to locate a 160* thermostat. I put in a 180* since OE called for a 195*. I tend to prefer it on the cooler side as well.