1986 4Runner Cooling system rebuild and problems
 

Hi all,

I've tried to do proper research on my questions, and I'm hoping you'll be able to fill in some gaps.

I just bought this car a few weeks ago, and I've been working to get it completely functional.

Vehicle - 1986 DLX EFI
Engine - allegedly rebuilt within the last 70k miles.

The cooling system has been badly corroded, via what looks to be galvanic corrosion. The pipe and thermostat outlet are exceedingly corroded. I'll attach photos of the system itself to this message.

Main questions:

1. The thermostat housings that I've been able to find to replace the corroded thermostat housing do NOT have a space for the temp sensor that's included in the original equipment. Does anyone have a recommendation for where to get this housing?

2. It sounds like (from my reading) that the sensor that screws into the original thermostat housing has something to do with fuel pressure regulation in hot soak situations. What does this sensor specifically do, and is this sensor necessary?

I've replaced the hoses, pipe, and radiator, and I'll be flushing the entire system after resolving this issue. Thanks for the help.

Wow some serious neglect

I might have one of those water necks with the bung for the sensor .I have to look

I am guessing used is the only place .

If the system was that bad just what condition are the sensors in??

Since that sensor or switch sends a signal to the ECU I would need to look it has been awhile as to what it does.

Didn't expect this, but rolling with the punches!

let me know if you have an extra outlet; otherwise I'll likely have one fabricated through a welding shop.

I've cleaned the sensor in the water outlet in question, but I haven't checked voltage yet. The entire system is coated in rust, so going step by step.

Here:
Attachment 111879

And my latest discoveries regarding temp sensors that are critical, yet not mentioned in FSM here.

Perhaps your using that location for your gauge sending unit but it came from the factory as the water thermo switch only on 4x4 applications with a green black stripe wire

connecting to the ecu

The factory temp sending sender is further back on the intake manifold a yellow / Green stripe wire