[slimsex]

Well i've owned 1997 Renault Clio for 11 months now, and although the engine is mechanically sound which has barely used up any fluids, I need to know whether it'll be wise to drain the car coolant and top it up with new fresh liquid and antifreeze as i've heard coolant needs replacing every 2-3 years - that correct? I bought the car with the coolant tank at the maximum line and over the last year it hasn't required any top-up in 6k miles. It's still almost at the maximum line.

Should I replace the entire coolant in the next service with fresh new water and anti-freeze with anti-corrosion?

[raskrutkaseo]

A good flush of the cooling system every 3 - 4 years is a very good idea. The flush includes draining the coolant from a warm engine and refilling it with clean water and possible some special cleaning stuff made specially for the flushing of the cooling system. Then some driving for at least fifteen minutes but preferably longer and after that draining again and then the real coolant goes in.

The anti-freeze/water ratio depends of the climate, in the Arctic its fifty-fifty but in more humane conditions its some 1/4 - 1/3 of coolant in the solution. The more anti-freeze in the water, the less effective the transition of heat from the engine to the coolant is. The guys/gals driving in the Tropics might consider using only some special corrosion inhibitor besides water. Running water only may be very bad, especially if the coolant touches parts made of different metals, like Aluminium, Brass, Steel and Cast Iron.

[StitsVobsaith]

You only need to bother if the coolant is looking nasty.

[Lolita Palmer]

I change my coolant every 12 months or 10,000 miles.

I also use anti-freeze (as you should) and also a product called Water Wetter, to keep engine temps down.

Some might say its not needed but then again I change my oil every 4000-5000 miles or 6month.

Gotta give an engine respect especially when its tuned.

[slimsex]

You only need to bother if the coolant is looking nasty.

Well, it does look brown (kinda brown on the container) and the water inside looks like it's a clear colour (not blue, green or pink - looks just like it's water). This is kinda why it has me a little worried. There doesn't seem to be any deposits worth mentioning in the container itself (a couple of very little metal rust deposits), but it gets me thinking whether there's any corrosion protection in the system or antifreeze for a start.

I've got a journey ahead of me next Friday, but seeing i'm having a little garage visit to Renault on Wednesday (replacing a dead bulb in the dial panel - cheap fix), I guess I could ask them to flush and top-up the system?

[raskrutkaseo]

You only need to bother if the coolant is looking nasty.

I kinda understand the attitude. There where you come from, the engines are Industrial Big Irons, it wouldn't matter much if the coolant is abundant in material of the Engine, there's a lot more Cast Iron for it to eat from. [thumbup]

In the smaller high tuned car engines made of such high tech materials like Aluminium and Magnesium it's totally different. One has to take care of the engine as it doesn't withstand prolonged abuse without problems. It's even obligatory to change the motor oil and filter after a given mileage!

[KahiroSamo]

the corosion inhibiters in the standard antifreeze (ethelene glycol, the green stuff) break down after a couple of years. that is the primary reason for changing out the antifreze every couple of years. this also helps prevent the galvanic action that can eat away at cooling systems. it's probably not a big deal if all the metals in your cooling system are the same (ex. aluminum block, heads, radiator, and heater core) but can be rough on engines with disimilar materials like my brothers 64 lesabre (cast iron block, aluminum heads, and copper/brass radiator/heater core). if you overheat the engine on a vehicle with aluminum head(s) you will most likely blow the head gasket(s). ask your mechanic how much the charge for a head gasket replacement is. you'll see that the 20 quid for a flush and fill is cheap insurance, and yes if the water is clear you do need some coolant for the corosion inhibition.