Dorman Diesel Overheating problems

[ploughman]

I know its not military but our group has a problem.

We would welcome any suggestion as to a cause and even better a cure.

 

The Dorman Diesel in our 12t Plasser Rail Crane has been overheating badly recently.

As part of the investigation our fitter has already examined and checked the water pump for correct operation and found no fault.

He has also done a compression test on all cylinders and found nothing to be concerned about.

The engine oil is staying clean and not becoming emulsified, likewise there does not appear to be oil appearing in the coolant.

If water is being evaporated in the exhaust this is not obvious, but may not be so easy to see.

Without boiling the amount of water loss is high even for a short period of running and only appears to be venting from the expansion bottle once the coolant boils.

A new radiator cap has also been fitted, in case this was the problem.

What is really baffling is where all the water goes. There are no obvious leaks when the machine is stood, and even after a short period of running, say 30 mins, then needs a top up of 2-3 gallons.

I am not sure what the total capacity of the cooling system is, I dont think either the Plasser or Dorman manuals gives us this figure, but a loss of this amount of fluid must be a good percentage.

[N.O.S.]

Certainly points to a head gasket or cracked head. If there is an oil cooler (oil/water heat exchanger), a problem here would be evident in the water or sump oil pretty quickly.

 

Big diesels can cope with a fair bit of water in the combustion chamber and chuck it out the exhaust without giving much sign of trouble (depending of course on where the failure point is), although a white exhaust is an obvious pointer to water.

 

Could the water system be pressuring with hot gases? have you tried running without the rad cap on to see if water is being pressurised? Are the cylinder liners wet or dry type? But again a perforated liner usually causes obvious contamination in either water or sump oil.

[cosrec]

Head gasket cracked liner or head. Water is being exposed to combustion temperatures and vaporising it out of exhaust Must have posted same time as NOS

Edited April 30, 2014 by cosrec

[N.O.S.]

Let us have the Dorman model number and drive layout at flywheel end - you never know…….

[rustexpert]

The original post doesn't mention any recent repair works.

I once built up a tractor engine and got the injector timing advanced slightly. Was fine until the first heavy loading made it boil quite well. It was the first suspicion due to the recent rebuild; on checking the spill timing I had just got it a bit out. Some engines injector pump drive train can slacken off and slip to retarded. If there is an auto advance on the injector pump this could have stuck.

I once drove a Ford Cargo which started to mysteriously "use" water but not really boil or overheat. Eventually we worked out the header tank had a leak under pressure; we had assumed the rusty water stains were from the water escaping from the relief hole by the pressure cap, the overflow pipe to direct this away being absent.

Another van I drove started using water. I wasn't responsible for repairs and replacing the cylinder head gasket was trusted to the particularly inept mechanic who opened the bonnet and started disconnecting stuff; I then mentioned that there was an additional symptom being rusty water in the passenger footwell. The mechanic was delighted he just blanked off the heater matrix so I then drove the van probably another 30k miles over two winters with no heater or demister. On an early frosty morning start a hot water bottle on the dash became the norm; it wasn't really that long ago either. Is there any remote cab heater matrix or such like on the rail crane?

I can also recall a newly restored Caterpillar tractor which had an overheating problem which eventually was found to be due to the radiator top tank being almost full of rodent nest material which wasn't visible from the filler hole.

[ploughman]

Certainly points to a head gasket or cracked head. If there is an oil cooler (oil/water heat exchanger), a problem here would be evident in the water or sump oil pretty quickly.

 

As I mentioned in my post.

The engine oil is staying clean and not becoming emulsified, likewise there does not appear to be oil appearing in the coolant.

I will try and locate the Engine type and layout but that may take a day or so.

 

Thanks for all replies so far.

We are taking the Radiator out next and sending that for testing.

If that fails then we have a spare engine but that will take some preparation as it was off a standby generator previously.

Be a bit like a pack change I suppose.

[utt61]

This is probably of no relevance and no help, but many years ago I had a similar problem with a 2-litre petrol SAAB 99, which would lose its water at a spectacular rate with no apparent sign of leakage, no oil in the water nor water in the oil, no over-pressuring of the colling system, and no sign of head-gasket probelms. The water just disappeared.

 

In the end I traced the problem to a leak from the water jacket round the inlet manifold (cross-flow engine, jacketed to keep carb warm) into one of the induction ports. Replaced the manifold and everything was fine.

[rubbatiti]

This is probably of no relevance and no help, but many years ago I had a similar problem with a 2-litre petrol SAAB 99, which would lose its water at a spectacular rate with no apparent sign of leakage, no oil in the water nor water in the oil, no over-pressuring of the cooling system, and no sign of head-gasket probelms. The water just disappeared.

 

In the end I traced the problem to a leak from the water jacket round the inlet manifold (cross-flow engine, jacketed to keep carb warm) into one of the induction ports. Replaced the manifold and everything was fine.

 

Renault 5 GT Turbos used to suffer something similar, the inlet manifold would become porous through corrosion allowing the coolant into the engines combustion chambers, quite often the engine would show no sign of emulsified oil too.

[N.O.S.]

….If that fails then we have a spare engine but that will take some preparation as it was off a standby generator previously.

Be a bit like a pack change I suppose.

 

In which case don't worry about the engine numbers - I was going to check on a surplus engine I have but you're well set up.

[ploughman]

Let us have the Dorman model number and drive layout at flywheel end - you never know…….

 

From the Docs that I have access to at home.

It is a Dorman 8JT

[jason1968]

I used to run a four cylinder dorman in a dredger and it used to boil with amazing regularity it turnwd out to be the radiator cores were partially blocked inside the radiator and years of just and crap had blocked the cores through the outside of the radiator it was that bad under load that it would blow all of the water out as a fine steam mist that you couldnt see1