Series 2 Flushing and changing coolant

Turboman said:

The only time it is important to open that is if you intend to change the head gasket.

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i'll keep that in mind. just found a couple of videos on coolant flush and change, they both said to do it. Glad i didn't. I'll check it's all in one piece when i finish work wednesday. it seemed okay, can't have broken as the bugger didn't shift a bit!

I have found the tap useful in the past when changing the thermostat.

You can push a piece of thin flexible tubing over the tap and drain a couple of litres of coolant into a container. This will have allowed the level to drop far enough to remove the thermostat without spilling any. This is useful when working in a garage to avoid having to clear up coolant spilled onto the floor. I had also only just filled up the engine with fresh coolant so could pour it back in without it going to waste. Antifreeze costs money of course.

Trench Rat said:

i'll keep that in mind. just found a couple of videos on coolant flush and change, they both said to do it. Glad i didn't. I'll check it's all in one piece when i finish work wednesday. it seemed okay, can't have broken as the bugger didn't shift a bit!

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I am sure a video on how to change coolant in a boat would say to get it all out.
But I don't. Because quite a lot of it is in a skin tank in the bilge,with no drain and no suction points, and there are several circuits for calorifiers, which have to be turned off with taps, or you will be bleeding calorifier coils for the rest of your life, and because there is about 40 to 50 litres of coolant per engine involved.
Not had any problem with partial changes and guesstimates, so that is what I do.

My warning about those taps is because I've known more than one person start with "I'll just free this tap" and end with "I have a crank in the block". Given that you can drin OK from teh bottom hose the risk is too high unless you are sure its free. The same warning applies to oil presure switches, leave well alone if working, a steel taper thread into cast iron.

If I remember correctly, the Series oil pressure switch thread is a straight type with a copper washer screwed into the alloy filter holder.

Are you referring to the Series engine in particular or oil pressure switches in general?

In general, my engine is a Perkins with the UNF taper thread. But it doesn't help that tapered thread switches can and do get screwed into a parallel thread designed for a seal washer.

rob1miles said:

In general, my engine is a Perkins with the UNF taper thread. But it doesn't help that tapered thread switches can and do get screwed into a parallel thread designed for a seal washer.

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Usually on the head or block, a better location than a Land Rover.
But also prone to failure due to oil leaking into the switch, I have changed a few of those over the years.

Webley1991 said:

I have read that some types of grease can react with the hose rubber and cause it to break down quicker. Again I cannot say if that is really true.

Wetting the inside of the hose end with plain water before fitting it can also help them push on easier.

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I've never experienced a problem but maybe that is because I've got rid of the vehicle before it happens. But when you think of other rubber parts that come into contact with rubber without problem, e.g. Drive shaft gators and track rod end boots etc, I doubt if there is a problem to worry about.

COL

Colthebrummie said:

I've never experienced a problem but maybe that is because I've got rid of the vehicle before it happens. But when you think of other rubber parts that come into contact with rubber without problem, e.g. Drive shaft gators and track rod end boots etc, I doubt if there is a problem to worry about.

COL

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Far as I can remember, rubber vehicle parts are made of nitrile rubber, which is resistant to oils.

Other kinds of rubber less so. And you can buy special rubber lubricants if you want to.

Turboman said:

The only time it is important to open that is if you intend to change the head gasket.

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May I ask why? Just curious why the drain tap is going to do a better job of draining the system than removing the bottom rad hose. Both are well below the level of the head...?

And even if a little spills into a cylinder, I would imagine that a lot more water could have already got into the cylinder, if the head gasket needs replacing.

TheMegaMan said:

May I ask why? Just curious why the drain tap is going to do a better job of draining the system than removing the bottom rad hose. Both are well below the level of the head...?

And even if a little spills into a cylinder, I would imagine that a lot more water could have already got into the cylinder, if the head gasket needs replacing.

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The water doesn't drain out of the block very well with the radiator empty.

And water will not only run into the cylinder bores, but down the pushrod galleries.

Head gaskets blow in different ways on different engines, and on an old Land Rover, water going into a cylinder, or into the oil, is not a common one.

Turboman said:

The water doesn't drain out of the block very well with the radiator empty.

And water will not only run into the cylinder bores, but down the pushrod galleries.

Head gaskets blow in different ways on different engines, and on an old Land Rover, water going into a cylinder, or into the oil, is not a common one.

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And it is sometimes prudent to clean all the waterways of residual gunge before filling it again ....

Turboman said:

The water doesn't drain out of the block very well with the radiator empty.

And water will not only run into the cylinder bores, but down the pushrod galleries.

Head gaskets blow in different ways on different engines, and on an old Land Rover, water going into a cylinder, or into the oil, is not a common one.

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OK, I take your point about not wanting to get water anywhere it doesn't really belong, but I still don't understand the advantage. Surely the only thing you could usefully do to help water drain to any lower drain points, is let air into the system, engine side of the thermostat. How does the drain tap make a difference with that?

Oh dear - I'm so awkward - I find there's nothing more satisifying than a nicely working drain tap especially on a 1960's engine...

....all that lovelly brass...

...oh oh oh - suit you sir!

TheMegaMan said:

OK, I take your point about not wanting to get water anywhere it doesn't really belong, but I still don't understand the advantage. Surely the only thing you could usefully do to help water drain to any lower drain points, is let air into the system, engine side of the thermostat. How does the drain tap make a difference with that?

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Surely you can do what you want?

I really do not care, I don't get paid to do this. I am just telling you what I have done, successfully, many times over the last 40 years or so.

If you don't want to do it, don't. If you want an argument, try your wife, or AG!

TheMegaMan said:

OK, I take your point about not wanting to get water anywhere it doesn't really belong, but I still don't understand the advantage. Surely the only thing you could usefully do to help water drain to any lower drain points, is let air into the system, engine side of the thermostat. How does the drain tap make a difference with that?

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drain bung or tap is the only way of draining the the block

I have a large old syringe - brass, about 1 1/2 dia, with a peice of plastic tube on. It is really handy for jobs like this as I have never found a block that drains well. Turkey basters and coolant hydrometers work too. Even if you are brave enough to open that little tap it usually blocks almost straight away. When I rebuilt my engine in situe (The Perkins is designed for "in-frame" overhaul) I washed down with soapy water then spent a lot of time with an airline getting everything clean and dry.
These work well:https://www.ebay.co.uk/itm/Gearbox-...020047&hash=item48a9dd2eaa:g:uSwAAOSw8R9cNb~z

Turboman said:

Surely you can do what you want?

I really do not care, I don't get paid to do this. I am just telling you what I have done, successfully, many times over the last 40 years or so.

If you don't want to do it, don't. If you want an argument, try your wife, or AG!

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Oh dear. I rewrote that post several times trying to get the tone right, but I obviously still failed. Sorry.

I wasn't trying to pick an argument. I'm genuinely interested. I may well have to cope with this at some point, but my experience of drain taps seems to be the same as many others, in that they are more trouble than they are worth, and they are best left alone. I know if I attempt to free it, I'm likely to just bu99er it up, and so I'm just trying to understand what causes the problem and whether there's another way around it. Weighing up the risks....

TheMegaMan said:

Oh dear. I rewrote that post several times trying to get the tone right, but I obviously still failed. Sorry.

I wasn't trying to pick an argument. I'm genuinely interested. I may well have to cope with this at some point, but my experience of drain taps seems to be the same as many others, in that they are more trouble than they are worth, and they are best left alone. I know if I attempt to free it, I'm likely to just bu99er it up, and so I'm just trying to understand what causes the problem and whether there's another way around it. Weighing up the risks....

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At the risk of upsetting the apple cart I have the following comments to make.

1) The drain plug was fitted for a reason. It is something that is difficult - and inconvenient to fix - but I'd prefer every vehicle I own to be in as good condition as possible, so I would fix it if needed. Sludge / heavy parts in coolant and oil always fall to the bottom of a system. The best chance of getting sludge out of a system is to use the drain plugs as they are usually near to the lowest points.

2) Anyone who has drained a cooling system (opening all the drain plugs and removing all the hoses - opening the heater controls etc) and then removed the engine from the vehicle is likely to have experienced a large amount of coolant STILL coming out of the engine making a right bloody mess! There is still an unbelievable amount of coolant remaining in the engine from the perpective of trying to keep your working space clean.

3) Mixing old and new coolant in the engine is something to avoid. It isn't completely avoidable unless you remove the engine and give it a good shake (see number 2 above) but if you are not careful all you are doing is diluting the good new coolant with the old. To my mind not removing as much of the old as possible is a false economy.

4) With a new to you vehicle where you don't know what coolant was used previously it is arguably best to flush through before replacing with new

5) Once you've chosen a product stick with that coolant type / product - avoid mixing different types - strange things might happen (see number 7 below)

6) Don't blindly use a coolant that is widely advised:- If someone has fitted a modern ALUMINIUM radiator to your classic car you need might need to use a different coolant

7) If you have other vehicles with aluminium radiators and would like to have "one coolant for all" you might come a cropper when using some coolants with aluminium radiators. In a worst case scenario mixing different types can form a nasty gloopy sludge that makes one heck of a mess. Some coolants are corrosive for aluminium radiators.

8) I avoid using tap water when mixing anti-freeze. I prefer to use distilled water. It is more expensive but as I've lived in areas where your kettle furs up rather quickly it is a step worth taking.

As @Turboman says - this is a forum - I'm just giving advice based on my experiences - even if you "disobey!" I'm sure we'll be able to get along just fine. I'm very much aware that my approach is a little more like the way many would imagine the white coat wearing pedantics in quality control would do it...

Oh yeah - I forgot to add some other tips I've learnt along the way.

Owning a 1990s Mercedes has taught me to be more wary of coolant choice - this isn't directly relevant to a stock series Land Rover but none the less this information might help.

Steel / iron engine blocks mated to aluminium alloy heads can end up with corrosion problems on head gaskets. As a result I now like to use Hylomar when ever possible!

Even though it isn't called for in the workshop manual for my Series 2a having seen the crappy thin gaskets that get given to you from most Land Rover parts sources I've boosted their sealing abilities by lightly coating the mating surfaces with Hylomar before fitting the gaskets.

Pitting on engine block and head surfaces can be helped by filling with epoxy fillers / glues. I think even GM recommend it on some of their engines (eeek!) so on parts of cooling systems where you get pitting on parts where hoses fit, epoxy might help you get through to the next MOT. On the whole, however, I have found the cost of replacing with new for the Series 2a to be quite reasonable - but - for the Mercedes it is usually a different budget busting price ball park...

....when fitting rubber / rubber-like plastic parts that are a tight fit I like to use KY jelly. I know it isn't exactly meant to be used for this purpose but it is famous for not eating into rubber. A light smearing can help you get over that ridge.