Tom, have you test fitted the head on the block in the car yet? curious as to whether that oil drain plug you got will clear. Had originally gone with something similiar on mine but before installing it changed to a threaded insert plug instead for fear of clearance issues and I just didn't like the look of it(extra weight!)

pics with big bolt plug and the more better threaded insert.

http://www.miatamx5.com/coolantreroute/reroute-001.jpg

http://www.miatamx5.com/coolantreroute/reroute-004.jpg

It clears OK on a 1.6

Yes it fits on a 1.6L with probably like ~1-1.5 inches to spare. I was running this in the brg for the past year without any problems, and of course you ask me this right AFTER I removed the engine so I can't even measure now.

Bumping an older thread because this weekend I'm going to attempt a spacerless re-route. I like brgracer's layout from a "most optimum" standpoint. I'm just trying to work up the courage to drill holes in the head.

And I like Uncle Arthur's idea from a low-impact standpoint, except for one thing- relocating the ECU's CLT sensor to the front water neck seems like it would give an artificially low reading, since there's mostly cool water fresh from the radiator hitting that spot.

Thoughts?

Regarding heater core flow and warm up. In this pic, could you drill a 1/8in hole in the thermostat, then plumb the heatercore off the location you have the big bolt in? I think that would allow a little flow to the heater core during warmup, but not enough flow to cause long warm up times. Am I completely wrong?

Stupid question, why is there a drain plug on the aluminum coolant reroute hardline?

Is it to burp air from the system?
http://http://www.miatamx5.com/coola...eroute-004.jpg

With only a 1/8" hole through the thermostat, the measly amount of coolant flowing through would probably take the path of least resistance and just go to the radiator, and you'd have very little heater operation until the thermostat opened.

My current plan of attack is a hybrid- take the heater feed off the Cursed Water Plug nipple, and fab an inline adapter to put the CLT sensor in that line. I may drill that nipple out and install something larger, like a 3/8" HB. I'm trying really hard not to have to drill a big hole on the other side.

Probably. Looks to me like that pipe is now the highest point in the system, instead of the radiator's top tank.

So, if it was lower that burp plug wouldn't be needed?

It was never really intended to be a burp plug. It was just on the pipe Paul found that fit in that position.

Later, when Paul had the piping re-done by Tim, this pipe ended up on another members reroute and was used to keep the heater core in use by running one line here(before the thermostat the pipe in question fed in the front) and leaving the other heater core hose going through the hardline under the manifold to the stock waterpump inlet location.

Thanks OG for clearing my head.

If you got rid of the heater core and did this type of coolant reroute, what will happen to the water pump when the car is warming up and there is no where for the coolant to flow until the thermostat opens? Will there be any damage to the water pump? This is assuming that the mixing manifold only gets water from the radiator and all other ports on the mixing manifold is blocked off.

Should not be? The pump is continuously flooded with coolant, and it is an impeller type pump, not positive displacement.

Forget about damage to the water pump. Zero circulation means uneven heating, probably localized boiling, no heat passing through the thermostat housing means it'll take longer to open... Not good.

You need some circulation through the engine. Always. Period.

Ok, so there should always be some sort of flow through the engine even when warming up.

Heater core circulation for the reroute is best; however, small holes drilled in the thermostat flange allow for some circulation and get heated water to the thermostat so that it can see temp rise and open.

How big of a hole on the Tstat flange can provide sufficient circulation , OG?

One 3/16" hole will move a lot of water. I would start there if I had it to do again. It is really a balance between getting flow and taking forever to come up to temperature in cold weather.

Thanks OG,

Since I just got my Tstat out of the car, I could make any hole to acommdate. OG, I am not running any Heater core, so water is pretty much all going thru to the Tstat at the back. From the photo on the OEM Tstat, there is already some relieve hole with a small metal plug measured at around 1/8. I'll have it enlarged to 3/16.

Also, does it matter if the hole be rotate on top or bottom? If it goes on the bottom will I be needing another hole at the top to let air pass?

I would put the hole at the top, but it really doesn't matter. Once the tstat opens, it will purge out most of the air.

Tom, first of all thanks for this thread! :bigtu:

Can you please post a pic of your engine bay with the reroute in place?

Thanks