Nissan Patrol and Landcruiser Overheating Problems

Time and time again, we are contacted by customers who have overheating problems with their diesel engines that they cannot rectify. Many have spent $3,000 to $4,000 on big core radiators, new water pumps, thermostats, fan hubs, chemical cleaning and more, yet have not fixed the problem.

The typical pattern is that their engines run hot under load (eg towing a trailer, going up a range, higher cruising speeds), rather than idling in traffic. As soon as they back off the load, then the temperature drops. It is particularly a problem with 4×4 and light vehicle diesels.

It seems that very few people (even those running radiator shops) realize that the engine oil has a crucial role to play in the cooling system. An engine oil actually has 5 duties to perform, and these are:

  • Effective Lubrication to minimize wear
  • Keeping internal components clean
  • Protection against corrosion
  • Cooling
  • Providing a fluid seal

A good strong supply of oil to all parts is crucial for effective cooling. It is particularly important to remove heat from around pistons. Any deposits around piston rings, top lands and skirts insulate against heat transfer. Sludge is a big problem, and can reduce oil flow by constricting oil galleries. It can reduce oil pump output. It can also insulate against heat transfer around internal oil coolers. Dirty sooty oil does not carry the heat away. It absorbs heat, but doesn’t disperse it as well as clean oil.

As several hundred of our customers have found out over the years, you can spend some pretty big dollars trying to sort out overheating issues. Our advice is to make sure the basics are right before you start spending big, on a trial and error basis. By that, make sure that the lubricating system and crankcase are clean, that the cooling system is sound and clean, and the thermostat is working, before you part with big dollars. If your vehicle was designed with a standard radiator, why should it need a big core radiator to fix overheating? Surely, it is more likely to be something basic creating the problem.

Solutions to your overheating problems

Our Flushing Oil Concentrate and Cleanpower pack has been solving such overheating problems in diesels for nearly three decades now. It does restore a pristine level of cleanliness to all oil wetted parts of the engine, removing the most stubborn sludge and even hard baked on carbon. When customers have tried everything else, and failed, this is usually the answer. If only they had come to us first, and got the basics sorted, they would have saved themselves big dollars.

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