Radiator purging after 5-10 miles
 

Just installed a new radiator and cap, upper rad hose and the thermostat is a couple months old. I was hoping that it was just the undersized radiator that had been installed during the engine swap. So after dropping my kid off at school I get home, not a far drive at all, and of course I hear this familiar sound:

http://i628.photobucket.com/albums/u...h_IMG_7470.jpg

So the only thing I can think of at this point, is the water pump, which makes sense since the water is just boiling, and should be cooling down if its moving through the radiator. It doesn't happen super fast though, which kinda throws me, granted, this motor has 160K on it. Water pumps seem super cheap on the 2JZ which is nice, but no clue if that's gonna fix this.

The other thing I've read is the heater core valve, but I can't imagine that would be making me boil like this. At the point that I took this video, the car wasn't overheating yet. If I only drive a mile or two it doesn't boil. If I drive stop and go for a 15 minutes or so, the water starts to boils out, and once it hits a certain level, basically once its all purged out, then the temp needle shoots up.

So water pump you think?

same problem with mine as well

I just had a similiar issue. The coolant in the reservoir was boiling and spilling over but mines didnt overheat. The two big issues is researching this may be a result of air in the system, bad head gasket or heater core. Tested the heater core valve, which seemed fine and it appears I may have a bad heater core. Now, I have no heat (didnt fix that yet btw).

I changed the thermostat and topped off the fluid in the radiator in garage and no more boiling of the coolant in the reservoir.

I have no heat inside anymore either. I used to, but after the V8 was pulled out and the 2JZGE dropped in, I have no heater anymore.

There is a special coolant fill procedure on SC400s you can look it up online.

I can almost guarantee this is NOT a water pump issue. this is an air trapped in the cooling system issue. again as posted earlier there is a special fill procedure for v8 sc's

I guess you cant read? he doesn't have the v8 in the sc400 anymore, he said he swapped a 2jzge in

do you notice if the fan turns on at all?
are you sure you bleed the system?
did you use oem parts or aftermarket parts?
new or recored radiator?

Yes as mentioned, all the V8 stuff is gone. Its all new direct replacement parts. I didn't buy the radiator from Lexus, or the rad hose. As far as the air in the system, I didn't follow any special procedure, outside of the fact I filled it up, squeezed the hell out of the upper and lower hoses to burp the air out, and even ran a rad conditioner through it just to be extra thorough. This isn't air in the system, unless there's some crazy special tool that snakes in there to find a hidden giant air pocket or something, lol.

For the 2JZ, any special way to put water in the radiator? I should note, that yes the Fan does spin, and doesn't have a bunch of play like some I've seen. If I spin it to the left, it comes to a stop nice and quick like it should, and it spins consistently when the motor is on. Really the only thing it seems is that the water isn't moving through the system like it should be, and its just heating up, which could be a weak or almost dead water pump. Its certainly not a fully dead pump if anything, because it takes a good few minutes of driving to get to operating them. Car's I've driven with bad pumps before start pinning the hot needle after not long at all.

Check your radiator cap.
When they go bad they don't maintain pressure well and cause the radiator fluid to boil prematurely. May as well just replace it and see if that works, the caps are usually only ~$15, and take like 10 seconds to replace.

Wow, you sure come across as cynical fella, my reading comprehension skills as solid I assure you. ;) I am an ASE certified Master Tech, as stated in the TIS manual They want the heater core filled separately from the rest of the cooling system as to reduce the risk of an air pocket. Or was this too changed in his 2jz swap!:egads: The point being unless the water pump is leaking or has a bad bearing on the impeller shaft there is NOTHING wrong with it.

There is virtually nothing on this water pump to fail short of a bad seal (which you would see an antifreeze leak) or a bad impeller shaft bearing (which you would hear rumbling away). In the 100's of Toyota's I have installed water pumps on (all due to leaking or regular maintenance when replacing a timing belt) NONE have ever had a bad impeller blade on them, not one single one. A water pump can NOT pump air, and that is clearly what is happening here. The only other potential issue I can see here as long as the head gasket is sound would be that the thermostat may not be of good quality, we ONLY install OE thermostats because they ALWAYS have the "jiggle pin" This pin helps bleed the cooling system of trapped air by allowing air to pass into the radiator and released from the system. A new radiator cap would also be sound advice at this stage, as we have seen a plethora of Toyota's have cooling system issues due to the radiator cap not allowing fluid to flow into the radiator from the recovery bottle thus collapsing one or more cooling system hoses.

Maybe the thermostat was installed backwards?
My car was actually doing the same thing after a month of swapping to a koyorad aluminum radiator. I realized my coolant was low so I topped it off. Figured I might as well pressure test it since its simple, sure enough found a leak on the lower radiator hose clamp. I just tightened it up and now it has been perfect.
Another thing to note, the Lexus radiator is a big hefty radiator, if you got an aftermarket one, i.e. AutoZone, Oreilley's, then you have significantly decreased the size of the radiator. That might be another potential issue. The radiator is to small to cool enough. But then again you said its after 3 to 5 miles which doesn't lead to radiator.