Over heating under load ZD30 DDi

My patrol overheated towing the boat , so much that engine stopped. The thermostat seemed to be stuck so replaced that.
Same issue with overheating now.
Complete engine replacement about 100k ago.
The original radiator still in the Patrol.
All I can see is either the system really needs flushing, or the radiator is internally corroded. No sign of damage outside.
Boost is set back to factory, intercooler is original.
Only engine mod. is a HPD air flow fitting.

Any good ideas?? Flush the system, replace the radiator, replace the thermostat (again)after checking opening temperature???

Get the radiator professionally cleaned. Don’t bother doing it yourself.
Make sure the viscous hub is properly working also.
These motors don’t overheat, even when under load so something is wrong.

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Do a TK test to see if the head is cracked.

Are you using the factory temp sensor/gauge or aftermarket unit?

Getting the whole cooling system flushed (not DIY), viscose fan "seems" ok.
Electric fan is ok, but no way to check if the ECU is actually switching it on other than when the engine is over heated. I will check next time it gets hot.
Only using factory heat gauge so not 100 accurate but a good indicator.
Looking at replacing the radiator--it is 18 years old.
We shall see.
Thanks Mudski

factory, but heating creates other issues as well as indicated temp. Actually loses a LOT of power. Following Mudski's list plus others so we shall see.

Quote:

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Originally Posted by Dr Gary

Getting the whole cooling system flushed (not DIY), viscose fan "seems" ok.
Electric fan is ok, but no way to check if the ECU is actually switching it on other than when the engine is over heated. I will check next time it gets hot.
Only using factory heat gauge so not 100 accurate but a good indicator.
Looking at replacing the radiator--it is 18 years old.
We shall see.
Thanks Mudski

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Get the engine at temp and see if you can stop the fan from spinning. I just use a welding glove or use a rolled up news paper. If you can stop it from spinning when the engine is running and hot, the hub is shot. The should be quite some resistance there.

Seems like I have two major issues 1) the water pump/viscose fan is suspect and 2) The radiator is 18 years old, so likely degraded inside.
Replacing the radiator seems better value than cleaning, the price difference is small.
We will pull the water pump and see if the vanes are intact, check what we can and decide on replacement or not.
I will report on progress as we go through the water pump and radiator replacement.
BTW, thanks for all contributions.

You should be able to make your own wiring to the fan if you want to control it manually. I did this with a previous car, fan stayed on all the time.

I think put the new radiator in, then flush the cooling system to remove anything from inside the engine block, water pump, etc. I just put 2 bottles of the nulon stuff from supercheap through my car, I was really amazed by how much brown stuff came out. I kept flushing with water until it came out clean.

Flushed the system, radiator was checked and really full of crud. Best solution was to replace it, which I did. Water pump "seemed" ok, but replaced as it was cheaper with the radiator out.
Because it had been over heated, replaced the thermostat and radiator cap.
Early test runs are ok so we will see on a harder test after the holiday traffic eases (or not!)
Thanks to all for helpful comments/recommendations.

Nice! Did you go genuine radiator? I'm thinking of adding a temp probe to the cold side of the radiator to monitor it's performance over time.

Quote:

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Originally Posted by Dr Gary

Flushed the system, radiator was checked and really full of crud. Best solution was to replace it, which I did. Water pump "seemed" ok, but replaced as it was cheaper with the radiator out.
Because it had been over heated, replaced the thermostat and radiator cap.
Early test runs are ok so we will see on a harder test after the holiday traffic eases (or not!)
Thanks to all for helpful comments/recommendations.

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Great outcome.
The factory units in the 3.p engines do a great job when maintained.
I doubt you'll have any issues moving forward.

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