Need help what are these coolant connections under egr?

US market hasn't been getting that arrangement, but Euro and Japanese markets do. The gray thing is an electrically-operated "flow shutting valve" that the ECM can use to influence the temperature of the water going to the EGR, cabin heater, and EHRS. There is more info in this thread.

This drawing's not from Toyota, but from an auto-research firm. Funny that they've labeled the same valve "flow shutting valve" in the physical layout, but "selector valve" in the schematic.

When the valve is closed, those paths only get cool water straight from the water pump. That cools the EGR better, and picks up more heat from the EHRS, but doesn't offer much heat to the cabin.

When the valve is open, hot coolant exiting the cylinder head is supplied, so you get better cabin heat, but less heat picked up from EHRS, and less cooling of the EGR.



One approach you can take in an engine swap is to buy the US version of the water-outlet fitting (which doesn't have the flow shutting valve), and cap off the extra coolant line coming around from the water pump.

 

@zoeboi954, I am from the UK and the engine I bought to upgrade my gen 3 is exactly like this one. Did you complete the project and how did you go about it? I have installed my engine with this selective valve and I am experienceing overheating issues, which might also be as a result of using the gen 3 water pump. Did you change anything or replace the selective valve with a non-selective valve.

 

This schematic could not be correct. Imaging the situation "ICE cold, coolant below 85 degree and therefore thermostat closed". It is a normal situation which happened nearly every day. When in this normal situation the "FSV" or "selector valve" is closed electrically, there will be no coolant flow through cylinder block and cylinder head, because any possible water-way is blocked. The main, big circulation is blocked through the thermostat, there will be no water flow, the water stands still and the head gasket will be blown because of locally heat. The way through the "FSV" or "selector valve" is electrically blocked, no water flow, so the water stands still. There must be a way for the could water to circulate through the cylinder block and cylinder head, which is not shown in this schematic.

 

Perhaps under the assumptions you're making, the schematic could not be correct.

That would imply that something is incorrect either in the schematic or in your assumptions. (Or possibly both.)

Two assumptions that might have to be examined:

• That the flow-shutting valve completely blocks flow when closed. (It appears to have a reduced-diameter orifice. There have been threads where it got drilled to a wider orifice.)
• That the ECM electrically closes the flow-shutting valve in conditions where overheat damage could result.

 

I agree the Selector Valve is essentially an electronic thermostat which has two redundant temperature sensors as part of its control logic.

Toyota’s gen3 engines have a thermal cycling problem which directly impacts the cylinders and was largely corrected in the gen4 design. Cylinder insulators at the bottom of the cylinder’s coolant passages are used to even out the heat distribution in the cylinder walls. The exhaust heat recovery/recirc system was improved. A Selector Valve was added. Oil burning and head gasket failures went away. Toyota improved efficiency lost when the 2010-14 low tension rings and pistons had to be revised on an emergency basis along with the expense of free installs for many gen3 owners.

It is no surprise that Toyota was willing to add gen4 complexity in exchange for reliability. It is also possible a gen4 engine in a gen3 cooling system is not cooled as well.

Some gen4 revisions

 

I solved this overheating issue by changing the selective valve for a non- selective one. I also changed the gen 3 coolant for a gen 4.

 

Hello,

is it possible to show a photo from the yellow marked direction so I can se what is the yellow marked "bump" in the housing is?
Best regards,
Bastian Fröba

 

Unfortunately I have installed it, however I went outside and had a feel. There is nothing there and it's not open because it's sealed but I think it's got some form of trade mark on it or some scribble.

 

Although I used the non-selective valve or the water outlet, I still retained the Y pipe that connects the bypass hose that ran through the back of the engine, from the water pump area to the selective valve. The only change I made there was replacing the selective valve with the water outlet and the connections remained the same.

 

OK, your are right. The "Flow shutting valve" has a hole of 3mm. via this hole water could always travel through it. And it opens itself via water pressure, which very little resistant. You can "blow" it to the open position very easily.

 

I wonder if it is designed to only stay "shut" when energized. That would be kind of a smart approach.