New member

Re: C18 - Overheating - Understanding of diagnostics sequence & sufficiency

Good day ,
My both caterpillar engine coolant temperature increasing upto 104 degree Celsius . Carried out follow as :
Replaced thermostat
Cleaned coolers
Replaced sensor
Inspected pump , working good .

But still temperature increasing, kindly advice .
New member

Re: C18 - Overheating - Understanding of diagnostics sequence & sufficiency

I have also experienced the same overheating issues, the engines are on a lightly used pleasure yacht, the year of the vessel is 2006, the warranty had expired, at 500 hours started experiencing an early overheating issue, when temperature would begin to rise I would reduce power and operate at 1500 rpm where temperature would remain at 190. Any increase in power would cause the temperature to rise. Now at 650 hours / June 20011 yacht now just over 5 years old, decided to have a Cat Tech investigate, performance sea trial was performed. Found all lead to the aftercoolers. He suggested we do the 1000 hour maintenance, removed aftercoolers and heat exchangers for service. After coolers and heatexchanger were slightly dirty but he felt not enough to cause the total problem.

While removing aftercooler on Stbd Engine the adapters that receive the raw water into after cooler was eaten up with corrosion and fell apart, (entry) further investigation showed the zinc just before entry into aftercooler in good shape, the same with the zinc on the exit of the aftercooler into the heat exchanger. The aftercooler was taking all the damage, I / we could find no real connection to the bonding system, other than the bolts into the block, which was not adequate.Salt water was destroying aftercooler, the corrosion allowed moisture (salt water to enter the air side). Hopefully we caught in time before we caused damage to the valve seats.


The adapters that allow the raw water to enter and exit were assembled with a very heavy paste, rubber O-ring, there was also the gasket that was in place between the aftercooler and block. Leaving little or no direct bonding. This isolated the aftercooler and the saltwater destroyed the aftercooler.


When we were ordering new aftercoolers, all part numbers were changed, indicating that there were new or different parts associated with this problem. There was modifications made to the aftercoolers.


Port Engine 659 hours Serial # CKH-01240

Stbd Engine 658 hours Serial # Ckh-01245


The Port engine was not as bad, but it was beginning.


We are forced to replace the aftercoolers after extremely light service. We are performing this now.


Super Contributor

Re: C18 - Overheating - Understanding of diagnostics sequence & sufficiency

The high coolant temp warning means the coolant temp exceeded the trip point (217F) for 30 seconds and the engine warning lamp is displayed. High coolant temp derate means the coolant temp exceeded the trip point (223F) for 30 seconds and the engine horsepower is reduced. The cause of the overheat will need to be diagnosed. The electronics only displayed the engine operating condition and not the cause of the overheat. It's possible all the heat exchangers are in need of service/cleaning. Cat parts are warranted world-wide as long as you have the dated receipt of purchase or the servicing dealer can provide the date a specific part was purchased. The Cat dealer network is second to none in customer support.

C18 - Overheating - Understanding of diagnostics sequence & sufficiency

[ Edited ]

The captain reported the overheating detected, when the yacht was underway at high speed. I approached a CAT technician and we had sea trials and electronic diagnostic test of the engines. We were given no printed sea trials record, but the technician advised the diagnostic codes and proposed to dismount and clean 6 coolers (water coolers, air coolers and gearbox oil coolers) and to order new spare parts for coolers upon defectation.

The diagnostic codes are:

E017 (1) - High Engine Coolant Temperature Warning.

E015 (2) - High Engine Coolant Temperature Derate.


I need someone to explain if  these codes explicitly point out the coolers issue (and can it be a particular cooler and not all six?) and if these codes exclude possibility of any other issue (like sensor malfunction or bad coolant?).

Another question is about CAT warranty for service works and parts for post-warranty engines. The service center offers 6 months of warranty for their works and parts, but the yacht will sail to other countries and therefore I need to know if I can get warranty support in other particular countries - can someone explain?