Radiator coolant

I recently bought a Series 3 Spider and was wondering if I should change the radiator coolant.

Is it important to use an ethylene glycol fluid as per the service manual. If so, does anyone know a brand and where it is available in the UK?

RobG

If you think that the coolant is old or has become ineffective from dilution it should be changed. You can get a simple tester from most auto places that will tell you the strength by using floating balls. Also the colour is a good indicator. Most anti-freeze in the UK is blue (standard type) or red (long life). They will change colour if they get contaminated.

It's not a big job so probably worthwhile doing anyway before winter sets in. Remember to open the heater valve and flush with fresh water.

The blue stuff is available everywhere but will probably need changing every 2-3 years. The red stuff is more expensive but lasts longer.

Best to stick with the one thats in it already.: Good quality, Paraflu or similar, well worth doing in my opinion.:

Backposts will tell you the difference between standard Ethylene Glycol, and the extended life Organic Acid Technology types, which do not, mix.:

i run mine on Volvo trucks own green coolant, i also run my bikes with it and never had coolant problems since....

So long as you do not mix the two types, no problems: Obviously the OAT's are less hassle, as they are of a much longer effective life duration, rather than the three year change, for EG stuff.:

……………..and always remember to use distilled water, not tap water as it really is not very good for aluminium blocks.

De-Ionised will suffice?:

I use the ready to use (ie no mixing with water) red stuff.

It is a lovely colour.

Think you mentioned previously David, you had the Organic Acid Technology/hybrid OAT. in your system? Way to go, for longevity and less attention, unless faults develop, requiring remedial action?:

Originally Posted by zulu ferret

De-Ionised will suffice?:

yes thats fine. When you buy it make sure you buy a a large container (over 5ltr) much cheaper than the 1ltr bottles in Halfrauds.

Stir this one up a bit. Anyone use a drop of soluable oil in their coolant for it's lubricating qualities? OK, the seals stop it going to advantageous areas, but it's thought provoking, or perhaps not?

There are products that supposedly add lubrication to cooling systems - one such manufacturer is Barrs Leaks and it was recommended as a coolant additive for Jaguar engines. However, the basic product is also a leak inhibitor and would eventually clog up the radiator - lots of V12 overheated and died this way. They now do a lubrication & corrosion inhibitor product, without the leak stopping properties which should stop the radiator clogging. Still has the whiff of snake oil though.

One useful coolant additive is a wetting agent which improves contact of water to metal. There's likely to be a product out there that you can pay for but a quick squirt of washing up liquid will also do the job.

As Cosmo say’s snake oil. A lot of these so called lubricants soften the seals in the water pump to the degree that it causes leaks. The Barrs leaks killed the radiator on my Lotus Elan by clogging it and caused even more over heating problems. I use a good quality coolant namely Bluecol and mix it 50/50 with distilled/de-ionised water. My understanding is the good quality ones contain some form of lubricant? I check the strength of the solution every year before winter and make a point of changing it every 3 years. Changing it on the S4 is a very simple job and I always flush through the radiator with a hose (as low pressure as possible). I have been doing the same thing for near on 25 years without any problems, not saying it’s the best method but it works!

As I posted way back, when doing PDI's back in the 60's a certain manufacturer sent out a bulletin, stating that all new vehicles at PDI time, should have a Dog Sh1te pellet, stuffed in the cooling system, before delivery to the customer. This was a part number from stores, but smellled, and looked like the Barr's product.:PS smelled, smelt?

Originally Posted by zulu ferret

... all new vehicles at PDI time, should have a Dog Sh1te pellet, stuffed in the cooling system, before delivery to the customer.

Jaguar's recommendation was two sachets at every service

Thanks to all who posted - a wealth of information.