Coolant system bleeding, wtf?
 

JDM ebay replacement engine, M-tuned cooland reroute. Engine runs and sounds great, but I can't get the coolant flowing through the upper radiator hose. I tried running the car with the radiator cap off for a very long time, fluid never went down and the upper hose never gets warm. The engine gets warm (215 degrees) but I have been careful not to overheat it. By cracking the hose on the IAC, I can get coolant to get sucked in, with a little coming out at the hose, but I don't know how much is in there net. The heater hoses are hot and the heater works, although it took a while. System seems pressurized, and water pump isn't leaking. The M-tuned Thermostat housing gets pretty hot, but not the hoses. I put it in like in the picture, so the thermostat should be facing the right way, with the pointy side facing the radiator, but no flow through the radiator. Lower radiator hose gets a little warm. What the hell am I doing wrong? If its air behind the thermostat housing, how do I get it out?

Put the front end up pretty high on jackstands and leave the rear wheels on the ground. Idle car with the radiator cap off until thermostat opens and then a couple more minutes. This helps burp the air out. Have done this a couple of times now.

That said, I don't have a reroute. Procedure may be different with a reroute but it is worth a try.

Make sure the thermostat housing and all the hoses are pushed as low as you can under the intake if you can get it there.

Well I pointed the front end toward a crow in a tree and ran the car with the radiator cap off. It didn't do anything until after it was warm for a while, then it overflowed quite a bit of fluid, then went down and I was able to add half a quart. The hose after the thermostat finally got a little warm as is the housing, but the housing before the thermostat is hot. The temperature gauge is reading a little hotter than usually, (to the left of center), but it was only idling and the coolant is routed differently now. I can't take it for a drive yet, perhaps tomorrow night. Do you guys think its ok? Why would coolant come out like that before going back down?

Coolant comes out because as the hotter fluid expands and without it being a sealed system, it bubbles up. What t-stat did you use?
Are your fans coming on?

I've always burped the system by letting the car run with the rad cap off until the fans cycle a few times, then I put the cap back on and fill the overflow tank to the brim and drive the car. Over a few cycles of warming up and cooling down, pretty much all the air bubbles will come out. I thought I had bubbles in my system after my reroute, but it turned out my overly active temp gauge was caused by the fact that it needed to be grounded.

Thanks! I am using the thermostat that came with the m-tuned kit. Perhaps it is a higher temperature one. The fan runs the whole time. I will try and fill up the reserve and go for a drive, as soon as someone can watch my kids.

I am losing my mind. The best I can get is the upper hose and radiator are a little warm. I repositioned the thermostat so the bleed hole was more upright. The temp is fine at idle but runs too hot when driven. There must be a big air bubble behind the thermostat housing preventing it from opening more than a little. I tested the thermostat and it opens at 180, my coolant temp was over 200. I am thinking about drilling a larger bleed hole in the thermostat or removing the stopper so the air can get out to actually bleed the system. Or perhaps tap into the thermostat housing and put a bleeder on there somehow. This is getting old. There is definitely pressure and the heater works great. Any more ideas?

Which end is the pointy end? The springs need to be facing the engine as they are what relax with heat.

The system won't take more coolant, driving it, idling with the front in the air with cap off, or just sitting overnight with the cap open.

The pointy end points toward the radator, the spring end faces the hot coolant coming directly from the back of the engine. I will try to take some pictures of where the housing is when I get home tonight and the kids are in bed.

Try running without the t-stat for diagnostic purposes. If you still have the problem, then think pump. Or rag in the hose... ;-)

Worth a shot, but the coolant pressure seems fine.

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Got me dude. But that doesn't seem to be reading 13psi.

That's just the fuel pressure gauge. If I pull one of the small coolant lines a tiny bit, it sprays out. I'll try making the hole bigger and go from there, I guess. Thanks for the suggestions.

If you have one of these fancy thinga ma-bobbers like I do...RADKITPLUSA, Vacuum/Filler, Cooling System

0 bleed time. I remember when I replaced this radiator on a 05 Ford Explorer. I did the same thing, left the cap off, bled it as much as it could but it would just overheat because there was a large air pocket that wouldn't go away. Sometimes the air pockets are very stubborn. But I don't know much about the coolant reroute so I'm not sure if there is an actual problem or just something simple like an air bubble thats being a bitch.

I drilled a 3/16th in the thermostat. Bled quickly and seems to work great, drove all around today, getting a base tune. Probably takes a little longer to heat up but I don't care, I don't drive this car in the extreme winters we have here. Car runs at about 175 degrees.

Why'd you post that pic of your piston?

I actually don't know.

Its not really that bad, just a little melted. I am in the process of building it.