My 1993 Toyota LandCruiser has started overheating

Question

My 1993 Toyota LandCruiser has started overheating

Toyota Toyota Advice Toyota Land Cruiser Toyota Land Cruiser Advice Toyota Landcruiser 1993

...

I have a 1993 Toyota LandCruiser 4.2 GX and have been driving it for years without problems. I have taken it for regular services. The last service was done about 3000km ago.

About two weeks ago I had the radiator flushed, as I was planning a long distance trip. After the radiator was flushed the engine started overheating. It never went into the red, but I questioned the mechanical workshop and they then told me to bring my vehicle back where they flushed the system again and then took the thermostat's inside out.

While flushing it, the pipes weren't disconnected from the engine. The vehicle still overheated. According to the mechanical workshop the head might have cracked, but they cannot give me any clear indication of what might have happened.

My questions are:

1. Is it normal to have an engine issue after flushing the radiator?
2. Is it normal to have this issue if I have never pushed my vehicle into the red and only drive it at 80km/h and have NEVER abused my vehicle.
3. When I took my vehicle back to the mechanic's workshop, it did not even have a miss in it, but the mechanic was pushing it to the limit for about five minutes while I was standing there. Can that cause damage to the engine?
4. Could the dirt in the radiator go into the engine when they flushed it, as they used powerful equipment to do that?
5. Could this dirt have caused the damage to the engine?

I am really very upset about my vehicle.

Answered by CarsGuide

21 November 2025

David Morley

The usual procedure for flushing a cooling system is to drop the existing coolant (usually by disconnecting the bottom radiator hose) fill the system with distilled water and whatever flushing chemical the workshop uses, restart the engine, drive it around for a short time until everything is at operating temperature, dump the water and flush mixture and refill the cooling system with the proper coolant.

You can also simply flush the radiator (and not the rest of the cooling system) by disconnecting the radiator hoses and running a hose through the radiator, usually in the opposite direction the coolant flows. But this is a much more simplistic flush and doesn’t change the condition of the engine crankcase’s cooling passages.

It’s possible that the flushing process has loosened some rust or scale that then blocked the cooling system somewhere else (the thermostat is a prime suspect) and if that’s the case, the process needs to be repeated until the water coming out of the cooling system is nice and clean and not tainted with rust or scale or anything else.

Revving the engine to get the flushing mixture to do its job is not really a problem, but could also be achieved by actually driving the vehicle (which would also get it up to temperature faster). But, really, provided the temperature gauge hasn’t been allowed to move into the red zone, you shouldn’t have damaged anything. But you do need to know why the operating temperature of the engine is now higher after a cooling system flush.

Disclaimer: You acknowledge and agree that all answers are provided as a general guide only and should not be relied upon as bespoke advice. Carsguide is not liable for the accuracy of any information provided in the answers.

My 1993 Toyota LandCruiser has started overheating

Comments