Tech – Replacing a starter motor on a UZJ100 4.7 V8

Tech – Replacing a starter motor on a UZJ100 4.7 V8

February 21, 2022 Club Magazine 0

A few weeks after the trip from Joel to Mundaring where I tried to go through the water hole, the engine didn’t want to start. After reading up on wat it could be, it turned out it was the starter motor.

Easy to do, so I thought.

More reading on IH8MUD forum was required and it turned out that the starter motor in the V8 engine is located between the banks under the intake manifold.

After deciding I would do it myself, I looked at getting the starter motor. As it is in an impossible location, I didn’t want to go with a generic brand, so I got a quote from Toyota for a genuine starter. They are definitely not cheap.

For fun, I asked the Lexus dealer in Osborne Park for quote. To my surprise they came back with $100 less then what Toyota wanted for a starter. The genuine starter was ordered and came in Perth from Sydney after only a few days.

In the meantime, I decided to change the coolant as well as it hasn’t been replaced since I bought the car in 2011, long overdue. Part of the service was to put in a new thermostat with gasket.

On IH8MUD many mentioned that the plastic t-pieces in the heater/coolant system were prone to be brittle and break overtime. I already had those t-pieces and the attached hoses but never had time to replace them. Now was the right time as the cooling system would be empty and I had enough working room to get to them as they are back at the fire wall behind the engine.

Another part required was the gasket between the intake manifold and the engine head.

When all parts were delivered or collected, I started to disconnect everything what was connected to the intake manifold or what was in the way to remove it. Air filter box, air intake hose, throttle body, fuel lines, injector connectors, vacuum lines etc etc. After a slow 4 hours where I checked everything before I remove anything, the air intake manifold was off.

There, stuck in the far end corner was the culprit: the faulty starter motor. It has been doing its job for over 19 years.

It took a few more minutes to get the three bolts out, hidden at the back, disconnect the wiring and out was the starter. I tested it and it was spinning slowly but it wasn’t moving out. Faulty for sure. After opening up, I could see the corrosion.

After cleaning up the space between the banks, replacing the t-pieces and hoses, it was time to install the new starter and put everything back in again. 

I noticed that I was missing one vacuum hose as the connection was open. I couldn’t find the hose initially as it was hidden behind the fuel rail.

Now the moment of truth: will the engine start…..

Yes, it did!! With a very fast spinning starer motor the engine came to life again. The new starter is a 2.0kW while the original is a 1.4kW model.

All in all, it took me two weekends working slowly, sitting on top of the engine under the open bonnet, making sure not to stand on anything what can break.

Work done:

  • Replaced starter motor
  • Replaced thermostat with gasket
  • Replaced heater t-pieces with hoses √
  • Cleaned throttle body √
  • Cleaned MAF sensor √
  • Replaced coolant √
  • Adjusted throttle wire √

I am glad I did replace the heater t-pieces as after 19 years sitting in the cooling system, the ends did break off.

Next job is to install the Long Ranger fuel tank what has been sitting in my garage for over 1 year.


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