I have taken my 130,000km 3.0 litre Isuzu to 3 local mechanics to ask why the old bus is running cold (according to the dashboard gauge). They all said that this model always runs cold as it gets older an explanation which totally baffles me. It probably reaches 35 - 40 0/0 but never higher. Otherwise the old bus runs exceptionally well as I've always had it serviced and sorted every year since new.

Has anyone else been given this strange explanation or knows if it's a thermostat or other problem.

 

Thanks in advance

I don't know that car, but conventional wisdom puts the blame on a stuck thermostat.

 

When I was, er, younger, replacing the thermostat was two or three bolts (ok probably seized) and needed a new gasket (and thermostat).

 

Has to be a cheap test (I've long since outgrown boiling the thermostat to test it).

 

Use a handheld infrared thermometer to test the temperature of the top and bottom hoses.

1 hour ago, yosib157 said:

my 130,000km 3.0 litre Isuzu

 

Did you buy it new?

No one else has worked on it?

You didn't notice until now?

 

As has been said the thermostat is stuck open or depending on the answers to 1 and 2 someone has removed the thermostat. 

 

Diesels do have a tendency to run cooler than a gasoline equivalent.

Did you turn the engine on?

1 hour ago, yosib157 said:

have taken my 130,000km 3.0 litre Isuzu to 3 local mechanics

Did you take it to an authorized Isuzu dealer? 

 

Local mechanics may not know. 

 

Not been to an Isuzu dealer for around 14 years since the warranty expired because of their poor service and mis diagnostic on two occasions. For years I had a regular COCKPIT mechanic who took care of the car for years and checked everything at service time. Unfortunately he left then we also moved areas. The last 2 services, suspension refurb, split pipe and all maintenance have been done by a local garage and I think their work is better than the Thailand average. 

The engine has been running cold for around 3 months and i have asked that particular garage plus 2 others in my area who said the same. Apart from the odd time, I have been the only driver of the car throughout it's long life and it serves us well. Other than this irritating fault, the car runs great.

16 hours ago, yosib157 said:

have taken my 130,000km 3.0 litre Isuzu to 3 local mechanics

 

where are you located, issan? 

Phanom Phrai -- Roi Et Province

 

Nothing harmful if it’s running cold unless you want to use the heater, if it has a heater. If the heater is never used, then the thermostat isn’t necessary, remove it and forget about it, the engine will be happier running cooler.

Maybe the Thermostat has been removed by a 'Mechanic'. What kind of fan does it have, is it electric, Viscous, or direct mechanical drive.?

 

 

18 hours ago, Crossy said:

I don't know that car, but conventional wisdom puts the blame on a stuck thermostat.

 

When I was, er, younger, replacing the thermostat was two or three bolts (ok probably seized) and needed a new gasket (and thermostat).

 

Has to be a cheap test (I've long since outgrown boiling the thermostat to test it).

 

 

Usually(??) the thermostat is built into the water pump, which is driven by the cambelt, so cambelt change and waterpump is common to do both together.

 

On that basis, just fixing a stuck open thermostat can be rather expensive.

 

 

Belts changed by my man at COCKPIT some time ago and yes, when we were all younger, a lot of us would do our own basic maintenance. Unfortunately old age and bad knees prevent me from doing a lot of even mundane tasks and I need to depend on others.

I don't know what type of fan it is but others have played around down there when it blew its radiator and a n other messed up with the a/c. Which reminds me, even the National Chain of 'specialists' Denso in Yasothon shared the old Isuzu engine myth.

I always believed cold engines consumed more fuel but hey ho, we are off to Roi Et in a few weeks so may ask up there. 

 

Thanks for your inputs

2 hours ago, novacova said:

Nothing harmful if it’s running cold unless you want to use the heater, if it has a heater. If the heater is never used, then the thermostat isn’t necessary, remove it and forget about it, the engine will be happier running cooler.

No it won't.

 

Engines run best at their correct temperature.  

19 hours ago, yosib157 said:

I have taken my 130,000km 3.0 litre Isuzu to 3 local mechanics to ask why the old bus is running cold (according to the dashboard gauge). They all said that this model always runs cold as it gets older an explanation which totally baffles me. It probably reaches 35 - 40 0/0 but never higher. Otherwise the old bus runs exceptionally well as I've always had it serviced and sorted every year since new.

Has anyone else been given this strange explanation or knows if it's a thermostat or other problem.

 

Thanks in advance

35 to 40 what.. Degrees ?

How are you measuring this ?

34 minutes ago, Daffy D said:

No it won't.

 

Engines run best at their correct temperature.  

5! Having grown up in the tropics where commonly most people delete the thermostats, why? Because the engine runs cooler, therefore running better. Heat is a killer.

40 minutes ago, Ralf001 said:

35 to 40 what.. Degrees ?

How are you measuring this ?

per cent --- my per cent symbol didn't work on my laptop so I improvised

 

6 minutes ago, yosib157 said:

per cent --- my per cent symbol didn't work on my laptop so I improvised

 

 

Faulty sender.