Cool runnings.

Well, another few weeks have passed and against all odds another few jobs have been ticked off of the to do list – the main focus this time round being the rather grotty cooling system which seemingly last saw anything that could be described as a ‘better day’ back in the late 1990s. The hoses were perished and swollen, the coolant a very dubious shade of brown and the fan belt, well actually the fan belt wasn’t too bad, but you get the gist of things.

Some replacement hoses were definitely the order of the day – luckily before its final journey to the scrap man the blue car generously donated the new top and bottom hoses which the previous owner had put on just before it came into my ownership. The remaining assortment of smaller hoses were sourced from Rimmer Brothers in the UK, as was a new thermostat and gasket.

Before fitting the hoses however, the system needed a thorough flush to remove the existing coolant and any associated sludge that had built up over the last 30-odd years. The system was drained by removing the bottom hose and both the radiator and block flushed and back-flushed several times until only clean water emerged. After removing the heater hoses and moving the heater controls to hot, the heater core had the same treatment (this yielded a particularly appetising pan of brown silty goo), as did the small diameter pipe that runs behind the carbs. I would have done the same with the steel water return pipe which runs behind the exhaust manifold but somewhat annoyingly this disintegrated in my hand when I removed the heater hose from its T junction.

Old Pipe Broken
There is supposed to be a pipe teeing off at this bend. Also note the silt.

Being a mild steel pipe, corrosion here is a common problem which many owners choose to rectify with a stainless steel replacement from Chris Witor. Given the fact that at this stage I was already cutting it fine in respect to my deadline of the 10th February All British Day, waiting a couple of weeks for a part to ship from the UK was a bit of an gamble so I decided to inspect the engine I had removed from the parts car just to see if its water pipe was at least serviceable enough to use as a stop-gap measure in the short term.

To my surprise, not only was the spare pipe in great condition but it was also copper rather than mild steel and therefore completely free from corrosion. I’m not sure if this is a bespoke item made by a previous owner or their garage (or their plumber) or whether these were readily available at some point. Either way it saved me a lot of time and worry (and money – the stainless item weighing in at around $80 including postage).

New Pipe
Once again the spares car saves the day!

Whilst I’d had some luck finding a replacement pipe, replacing it wasn’t quite as straight forward as I had hoped. The pipe is easily freed from the block – is is held on by a single bracket at the rearmost exhaust manifold stud, two heater hoses and a compression fitting at the water pump end (I’ve heard these compression fittings can be a pain to undo but mine didn’t put up a fight). Getting it out is less easy – certainly on the S model – as the power steering pump and bracket preclude it from being pulled straight off of the car.

After much wriggling around, trying to find that one sweet angle at which it would clear both the exhaust manifold, the power steering pump and the radiator, I gave up and decided the easiest option was to remove the manifolds to give myself a bit more room. Although not a task I had planned to do, it’s not the trickiest job in the world (providing you don’t encounter any non-compliant studs) and it gives great access to the coolant hoses at the rear of the block, thus making replacement a lot easier. Removal of the inlet manifold (complete with carbs) just requires the disconnection of the throttle and choke cables, a few fuel, vacuum and PCV hoses and nine nuts (six of which also hold the bottom of the exhaust manifold in place). Removal of a further 4 nuts frees the top of the exhaust manifold, which can then be pulled gently away from the head.

Manifolds Off
Access to various nooks and crannies drastically improved.

With the exhaust still attached, the manifold is only free to move about an inch or so – but luckily this was all that was required to free the water pipe from its small and rather toasty prison. The old one was removed (and promptly chucked in the bin) and the new copper replacement fed in to take its place. I used a little bit of PTFE tape around the compression fitting to ensure it was watertight but other than that the fitting was a thoroughly unremarkable event.

Whilst the manifolds were off I replaced the various heater and other hoses at the rear of the block burning through my stockpile of new (well, newish) jubilee clips. I used the proper, correctly shaped hoses rather than just lengths of generic half inch heater hose as a) they look neater, b) it reduces the risk of kinking and suppressed coolant flow and c) they’re really not that expensive in the grand scheme of things.

Heater Pipes New
New heater hoses fitted.

With the hoses replaced, the manifolds were reattached to the head using the original gasket which looked to be in good condition. I was careful when tightening the manifold nuts not to go overboard with my crazy Popeye-esque strength just to avoid any sheared studs and heartache. I came away unscathed in this respect.

Next I turned my attention to the larger hoses – both of which needed some Stanley knife-based ‘adjustment’ (this does not usually bode well for the integrity of my fingertips). The car has two electric cooling fans fitted at the front of the radiator which I presume used to be controlled by a long-defunct thermo switch which was mounted on the front slam panel. When this failed the previous owner ran a bypass circuit into the car where a small toggle switch could be used to control the fans manually. This was seemingly never actually fixed to anything and was just floating around beneath the dashboard. This, coupled with the fact that all electrical connections had been made using insulating tape, spurred me on to rectify the situation.

A while ago I had purchased a Davis Craig thermal fan switch together with a adaptor kit to enable the probe to be fitted properly into the top hose, instead of hanging out one end of it which looks untidy and, from experience, invariably leaks. Fitting was fairly simple, 17mm of hose is cut out and the adaptor is fitted in its place. The temperature probe fits into the adaptor and runs out to the thermo switch – which I mounted on the slam panel using the same holes which held the bracket for the old switch.

New Top Hose
Top hose with adaptor for temperature probe.

Two short lengths of wire were then cut and used to join the thermo switch back to the original fan wiring loom, the result being functional, although not exactly factory (I’ve never really been a fan of these aftermarket thermo switches with their very obvious and messy probe cable) .

Termo Switch.jpg
Fan thermo switch.

For extra control and as a backup I also ran a bypass circuit into the car – although unlike the previous owner I went the whole hog and terminated in a proper automotive toggle switch which was mounted to the lower edge of the dashboard. Hopefully I’ll never need to use it but it’s reassuring to know it’s there just in case.

Toggle Switch.jpg
Emergency fan override/something to play with in traffic jams.

The bottom hose also required some surgery as it originated from the parts car which lacked power steering. The S models did not use the same single-piece bottom hose but instead used two shorter hoses connected by a metal pipe which is of small enough diameter to pass between the power steering pump and its pulley without being chafed. Cutting the middle section out of the bottom hose and just using its two ends did the trick.

New Bottom Hose and Belt.jpg
Bottom hose and new fan belt.

The connecting pipe for the two bottom hoses is also mild steel and mine was quite badly corroded at one end – although in this case enough metal remains for it to be used quite safely in the short term. A stainless steel replacement has been ordered from Chris Witor but in the meantime I used some JB Weld epoxy to fill some of the depressions left by corrosion just to help the bottom hose seal as well as possible and to prevent leakage.

When the replacement pipe for the lower hose arrives I plan to run a coolant flushing product through the system before I drain and re-flush the radiator, heater core and block. That should hopefully shift any remaining gunk and ensure the car keeps its cool at least for the next few years.

So that’s the cooling system dealt with for now – there are just a couple of minor jobs to  complete at this stage and she’ll be good to go. I’m looking forward to getting out and about and exploring some of SA’s beautiful countryside in the old girl.

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