coolant flow question
 

Im doing a 1.8 swap and while cleaning up the motor today i noticed the small fitting that comes out of the thermostat houing has a hole in it.
there are small hoses goes from the tb to the thermostat neck and from there to the side of the engine by the water pump.
all other fittings seem to be in good condtion except the t that comes off the t-stat housing. Can i just pull out this t and plug the hole in the housing and run one house from the tb directly to the wp fitting? witch way does the water flow? will this effect anything? also note i will be installing a ms to run the motor if that changes anything with the iac and need for the lines at all?
sorry if my spelling isnt good and my puncuation is lacking also.
any help apriciated

That's not a good idea. The purpose of that fitting (in addition to providing a return from the TB) is to provide a leak path to circulate water past the thermostat so that it opens in a timely manner. Without that leak path, your thermostat will open very late -- your water temp gauge will nearly peg before it opens. This is a byproduct of using an engine meant for transverse mounting in a fore-aft configuration.

The better solution is to do a coolant reroute and remove all of that stuff completely. I just did one and it works great. All the little hoses are gone.

ok where can i find more info on this ccolant mod. what did you use? im sure there must be a cheaper way than the big money kits. im not a fan of kits anyway.

Easy Coolant Reroute – part 1 — revlimiter.net
Sorta-easy Coolant Reroute – part 2 — revlimiter.net
The Coolant Reroute Strikes Back — revlimiter.net

This is about the cheapest way to pull this off and have it be effective. The M-tuned/SuperMiata is a nice option and has better firewall clearance, but most people feel the thermostat opens too late.

You can also go nuts and start drilling into your head for an even more custom solution, but that will happen if you search!

ok that looks great and all but this still uses the small hose from the tb housing. so this really didnt answer my?

i do have a neck from a 1.6 are they the same?

I just posted a bunch of pics on my reroute in my build thread.

Since I'm on a budget and I have a 1.6 parts engine in the garage...I was running doing it this way
1. Install thermostat in the back of the head....put the temp sensor on the head where there is a plug now, use the 1.6 thermostat housing on the back, and run a house down the hot side for a reroute..and freezeplug the front....or just swap the neck from the 1.6 to the 1.8 and fix the broken part and maintain factory coolant flow....I can't justify over $150 in parts for a cold side reroute....any input?

The main reason for a reroute is better and more even cooling, especially for cylinder #4. That's why I did it.

If all you're trying to do is minimize expense, why don't you just pick up another 1.8 waterneck with a good "T" for cheap? There might also be a brass fitting at the local hardware store that can substitute for the "T." It's easy to pull the "T" out, drill and tap for 1/8" pipe threads.

Your 1.6 waterneck might work. Takes a different upper radiator hose. There might also be clearance issues with the intake. Those should be obvious.

https://www.miataturbo.net/attachmen...ine=1360602321
https://www.miataturbo.net/attachmen...ine=1360602321
https://www.miataturbo.net/attachmen...ine=1360602321

The second image is blocked through work, so I don't know if it still links. None of those diagrams show the hose that goes to the factory oil cooler along the cold side, which then goes into the TB. You can cap off the coolant lines on the valve on the TB, but the electronic parts need to stay hooked up if you want A/C and P/S idle bump. I've been debating deleting mine and setting idle at 950 all the time, the harmonics of my interior panels are better up there.

More info here: https://www.miataturbo.net/race-prep...y-style-49344/

In short, I believe you can cap off the water neck line and run the hose to the WP temporarily, as that looks like that's where it goes post-reroute. Do not do this. Keep reading, but you can not bypass the line through the water neck without relocating the thermostat because the factory design uses this hose to run hot coolant past the thermostat for proper function.

those lines have nothing to do with a/c and/or p/s idle bump.

nice try though.

you could have read the page of the FSM in which you sourced the first imagine and it would tell you exactly what the lines in the TB to the air valve are for, instead of posting non-researched, incorrect, drivel.



God i really fucking hate reroute threads.

Braineack, that was my intent, but my wording left it murky. Fixed it.

rawr

Am I always supposed to feel like I'm being trolled on this forum? :giggle: XD

This wasn't even a reroute thread. OP asked whether he could delete the bleed line from his front thermostat housing because his T fitting was leaking. We correctly told him that if he did that he would have issues with delayed opening of the thermostat.

Now, you enter and state "[i]n short, I believe you can cap off the water neck line and run the hose to the WP temporarily, as that looks like that's where it goes post-reroute." This is incorrect and will lead to late thermostat opening issues.

So, you see, you're not being trolled. We're just trying to protect OP from bad info.

Then where does it go if you brass plug the neck? All the diagrams I see show it as going through the oil cooler, then TB, then water neck, then the turbo and then back to the mixing manifold/water pump inlet. With no water neck and no turbo I can assume that you then plumb it from the throttle body to the mixing manifold.

https://www.miataturbo.net/attachmen...ine=1360608303

Is this incorrect? Should it return to the upper radiator hose instead?

correct. it ultimately goes there anyways...

You're really not getting it Scary. OP is NOT doing a reroute. If you don't move the thermostat to the back of the engine, you MUST keep the bleed line at the water neck for proper thermostat operation. If you move the thermostat to the back of the engine with a reroute, then the water neck bleed line (and the water neck itself for that matter) no longer has a function.

you're assuming I even read the thread...i scrolled straight to pictures and happened to catch a few lines of text unrelated to anything.

Big picture guy!! I like it.