Perkins 4108 Cooling System - Overheating

[Travelmate]

Having problems with a friends Perkins 4108. Continually overheating over 1500 RPM under load. So far isolated the raw water system (OK), disconnected the house heat exchanger (no effect) but think the engine has isolated hot spots especially near the temp sender at the rear of the engine.

What can I use to de-scale the motor. Be aware that we are in Langkawi (Malaysia) where there is not a lot of chandlery type shops. Have heard that Caustic Soda (drain cleaner ) can be used - but at what strength and what is the procedure for its use.

The engine was overhauled some 5 years ago in Turkey and a larger engine water heat exchanger fitted. Also the fresh water pump was replaced some 2 years ago with no effect.

Can it be possible that the head gasket fitted has some through holes missing.

Just think the engine needs internal de-scaling.

Your thoughts please.

 

[narooma]

Just think the engine needs internal de-scaling.

Would agree with your diagnosis. Recently rebuilt our Perkins and although it was not overheating prior to the rebuild, it now runs at 5deg. cooler and and the amount of water coming out of the exhaust pipe is three to four times as much as before.

 

[pappaecho]

I am assuming that your engine is direct cooled and not indirect.
My 4108 had a complete instrument cluster including temperature gauge which never read anything! Which as it happens was correct, as the temperature of the seawater should be about 50 degree C to prevent salt deposition. Normal physical chemistry dictates that as you increase the temperature so does the solubility, but sodium chloride has inverse solubility which means that it is less soluble in very hot water as cold, and thus when it gets over hot, it throws a deposit in the worst possible places.
The best flushing product is Sulphamic acid, which is a weak organic acid. It is NOT sulphuric acid, which is what is put in batteries. In Malaysia, I am sure that if you search in suppliers to lorry and transport companies you will find a flushing system for large diesel engines. Failing that a weak solution of hydrochloric acid will do. In the Uk the Best source of that is "cement remover" sold in builders merchants to remove cement stains on walls. I would ideally allow the engine to pickle for several days, before pumping out into a receptacle ( to see what comes out). Good luck

 

[capsco]

Has it overheated eversince the overhaul? there are 2 different cyl/head gaskets for your engine, one is for a raw water cooled application, the other for freshwater cooled, they have different numbers of holes in them.

 

[Billjratt]

Try the 'laying on of hands'...
One hand at each end of the various coolers (depending on the model).
With the engine running you can feel the temerature gradient across the cooler and assess it's functionality. The oil cooler on mine has very little at the "hot " end and is cold at the other.
The main exchanger at the back has a considerable variation from one end to the other.
The gearbox is just cold.
Similarly, touch the freshwater pipes and see where the hot/cool bits are before doing anything rash.
Coca cola has been known to descale things if you can't get aquafuerte or similar.
I'm in the process of replacing all the copper piping in the saltwater circuit with clear plastic to cut down corrosion and also to see what, if anything, is happening.
Best of luck.

 

[pcatterall]

Mine had same problem. It developed quickly so initially I was looking for something obvious.
Discovered Heat exchanger needed cleaning but believe that very heavy build up on elbows ( where the section was 75% reduced) was intial problem. Had to get them fabricated but they were cheaper that way in any case.
Regards