A bit of Hambo'ing, some YouTube and a trip to Repco.
#1 sons car overheated on Saturday, got it home on a flatbed. Checked a few things, refilled it it water and I drove it for 30 mins. All seemed fine.
When to go to work this morning and the check engine light came on at the bottom of the hill, he drove it back up with a bit of steaming.
I took him to work at 6am
Worked out it may be a faulty thermostat as the water pump was still going (dont know what the impellers will be like).
Came home, took the old thermostat out and dropped them both in an old jug, stuck a IR thermometer on the water to check the temp, the new one opens up at >82°, old one faaaked.
Win ! Wouldn't be attempting this on a modern vehicle but ok on a 23yr old very simple 2.7L Petrol Hilux.
UPDATE: What a work in progress.
So after the above Repco thermostat.
Replaced ECU temp sensor (Bursons)- still check engine light fleeting.
Cleaned and checked MAF sensor - still check engine light fleeting.
Replaced Radiator as it had a hole in it - still check engine light fleeting.
Flushed engine with demin, then coolant system flush, then filled with new Toyota coolant. No leaks now, closed cooling circuit. The coolant in there was disgusting, it was full of bars leak crap.
Replaced ECU generic temp sensor with a Toyota sensor - still check engine light fleeting.
Replaced generic thermostat with a Toyota stat - still check engine light fleeting.
Replaced radiator cap as the suction back from the overflow wasnt working - still check engine light fleeting.
Filled cooling fan viscus hub with new silicon oil - still check engine light fleeting.
*Cooling is perfect !
* Took to Toyota, they tried 3 service laptops before being able to read the code (1 hour work in the carpark, no charge
) - PO325 Knock Sensor
The Toyota tech said he would be very surprised if the sensor had failed.
*Son works 6 days a week, its hard to get working on his car and he's happy to drive with check engine light on... but the car is unsellable with this problem.
Ordered an Ali Knock Sensor for $15, still the same check engine light pattern.
Replaced cheap Ali Sensor with original Toyota knock sensor. Cleaned the faces of the sensor port and the sensor seat with scotchbrite for a good earth. Cleaned sensor wire male pin with needle file.
Checked all wires in the loom, traced it back to the ECU loom plug, belled out 1 ohm so perfect connection pin to pin, cleaned all plugs on the ECU, and reseated them all. Pulled the sensor wire and cleaned up the female pin connector with a fiberglass brush and roughed surface with a 1mm drill bit.
Plugged in, no check engine light and he has now driven for 2 days and 150km with no light coming on.
A coincidence that the check engine light was coming on after it overheated ? Threw us off course a bit but we got there in the end with only money wasted on a couple of generic sensors.
Faaaken car was nearly more work than his bikes