I have owned numerous pre and early post war cars over the years, nowadays as a hobby, as a youngster as daily transportation. As a matter of necessity I learned the skills required to keep these cars mobile, sometimes carrying out major repairs in a weekend to allow me to drive the car to work on the following Monday morning. Whilst I cannot claim that I always enjoyed this activity, it provided a good grounding for the hobby I now enjoy!
One problem that has affected many of the cars I have had the pleasure (or pain) of owning, has been an overheating engine, a reconditioned radiator has not always solved the problem.
Attending motor shows and events, I have often heard exhibitors complain that their motor car overheats in traffic. Some realise that a problem exists, whilst others attempt to justify the problem, by trying to persuade listeners that traffic jams didn’t exist in the 1930s and the engineers who designed the car did not account for this in its design. This is nonsense, the first thing man invented after the motor car was the traffic jam, in fact I am sure that they have been with us since the days of the horse and cart.
From my own experience of tinkering with ancient motor cars, I have found that the overheating issue is usually quite cheaply fixed. The problem will almost always be a clogged water jacket, this problem exists on all motor cars with water cooled engines, whether manufactured by Daimler, Aston Martin, Triumph or Morris.
Dipping the water jacket for evidence of silt.
The impurities in the coolant create an electrolytic action between the different metals used in the construction of the engine, over many years it will have combined to produce a gritty sludge in the water jacket, this will have a sand like consistency, but often, especially in the case of Daimlers of the type I enjoy owning, around number six cylinder, it will be more like concrete. Daimler engines slope towards the rear of the car and as the silt builds up, and the temperature increases, it solidifies. On steep hills and fast runs, the coolant is unable to perform its task and the temperature guage sends the warning that something is amiss.
The photographs show my 1934 Daimler 20hp Limousine, the previous owner, very honestly, had warned me that the engine suffered from overheating. I had to remove the cylinder head to free off a couple of seized valves and knowing that it had not been off for decades, I took the precaution of cleaning out the sediment that had built up in the water jacket. I have carried out this procedure on dozens of engines and am always amazed at the quantity of muck to be found in this area of the cooling system. I can assure you that the simple addition of a ‘coolant flush’ in the radiator will not shift this debris, in some areas of the water jacket, it is so well compacted that it requires considerable effort to break it up.
Evidence of over two inches of gritty sludge.
I placed an old plastic baby bath beneath the sump of the car to trap the debris, then removed the engine’s drain tap and ran a slow water hose into the water jacket. As the clean water gently flowed through the engine, I poked and prodded the water-ways with different lengths of wire. The water running out of the block was bright orange and the silt captured in the bath, was just a proportion of the total amount contained within this engine, the remainder escaped in an impressive orange trail along my sloping driveway and out onto the road.
Some of the sludge was captured in the bath, the rest ran down the driveway!
The sludge remaining in the bath filled a child’s seaside bucket sufficiently well to build a nice mud pie. You may think that this is an unusually badly blocked cooling system, think again, I have regularly flushed these quantities out of engines of two litres ot thereabouts. If your car has a good radiator and yet still overheats, I would, in nine times out of ten, put money on this being the cause.
This is hard to believe, but is true – a mud pie made from the captured silt flushed from the 20hp Daimler engine.
The Daimler LQ 2-20 engine has no external core plugs, all of the sludge had to come out of the drain tap. Those of you with later cars will find that a good deal of silt may be flushed out without taking the cylinder head off; simply remove the thermostat housing and knock out the core plugs, run the water hose through the thermostat housing and prod wire into the core plug apertures, although this may not be quite as effective as carrying out the job with the head off, it will certainly be worth the effort.
Water pump to cylinder block casting was blocked.
Another issue came to light when I removed the short hose connecting the water pump (which is mounted behind the dynamo on this model) to the engine block: The alloy casting on the block was clogged with a chunk of multi coloured debris, this had hardened to the consistency of concrete. Another lump was to be seen in the water pump outlet adjoining the casting. This compound was over an inch thick and could not be removed by hand, but had to be broken up with a screw driver. A small aperture about the width of a pencil, was all that prevented this from becoming a total blockage. I suspect that the location of this debris is due to the chemical reaction between the iron cylinder block and the alloy water pump inlet, the bright colours, I imagine, were caused by chemicals in the anti freeze, which is well past its sell by date!
The Lanchester 11 saloon I have since purchased also has a dynamo mounted water pump, I removed this during the reinstatement process and found a total blockage in the same location (at the point where the alloy water branch connects with the engine block), on this particular car I was tempted to leave this area alone as the hose and clips connecting the pump to the water branch had the appearance of being almost new, this would have been disasterous, the engine would have overheated, water circulation being an impossibility. The interesting thing about this particular engine was that the water jacket and radiator were in perfect condition and completely clear of silt.
Hose clips looked good from above.
Unless I know that all of the hoses and clips have been recently replaced, I replace these on any car that I buy. The hoses looked fine on the LQ2/20 and some of the clips looked almost new when viewed in situ. Once out of the car and on the bench, every one displayed evidence of corrosion on the underside, each one having lost at least half of its original thickness to rust.
All were rusty on the underside.
Another problem that I have experienced with old hose clips concerns the threaded part of the assembly, the screw can simply break free, allowing the clip to suddenly open, a visual inspection will not show any defect and it is impossible to predict when or if this may occur. If you have any doubt about the age or condition of the hoses or clips on your car, I would recommend that you replace them all.
Before reassembly I flushed the radiator using a descaling chemical, very little debris was evident. Having replaced the cylinder head, I refilled the radiator with a high quality anti freeze which contains a corrosion inhibitor, hopefully this will be good for the next few years.
