170 - change coolant 3 yearly?

[mckcol]

SLK 320 Coolant, should this be changed every 3 years? I have seen 15 years mentioned for other cars

If changing, how much antifreeze do I need - and am I best to use MB stuff?

Regards

 

[Hertfordshire Merx]

Yes, the service recommendation by Mercedes-Benz is every 3 years, I would think its best to use Mercedes-Benz coolant but any other good quality anti freeze would suffice I guess. Mix it with clean, fresh water 50/50 mix. This will give you protection down to -37c and the correct anti corrosion level.

Did you say 15 years for a coolant change?? I dont think I would wait that long and the chemicals will lose their properties hence the 3 year duration for replacement. Anti freeze contains a corrosion inhibitor as well which also depletes in strength.

Hope this helps...

 

[rf065]

MB recommend 15 years for the coolant in my 2005 CLK.
Modern coolants are very different to the stuff we used years ago.

Russ

 

[jamesmc]

MB recommend 15 years for the coolant in my 2005 CLK.
Modern coolants are very different to the stuff we used years ago.

Russ

Interesting point. I have a 1999 CLK 230k.

On older cars the service manual may say three years but, as you suggest, coolant properties have improved to the point where your car manual (CLK 2005) takes account of that and states 15 years.

So I'm wondering what might the MB benchmark (on coolant - were not talking ATF changes here ) now be?

 

[Cole@MBS]

Last time i looked it was 15 years, might be different now but i dont think so!

 

[rf065]

This link claims 5 years & that it is used by Daimler Chrysler.

http://www.valvoline.com/pages/products/product_detail.asp?product=10

Russ

 

[jamesmc]

Oh no..... another vague area of MB servicing.

 

[Uncle Benz]

Perhaps bear in mind that we now see quite a few older 170 slk's with rotting head gaskets just over the 100,000 mile mark. An early coolant change might help to stave this off.

 

[wireman]

I have never seen any antifreeze with a 15 year life, the longest life stuff I have seen recently is 5 years, sold as longlife. The normal cheaper stuff has a 2 or 3 year life.

What the difference is I dont know but for me the 2 year stuff is fine and does not cost as much.

It is not so much the antifreeze properties but the anti corrosion additives properties that should interest us, if the stuff stops being a corrosion preventative all manner of ills will be manifested upon the engine and radiators, for this reason I take the trouble to change it at 2 year intervals regardless of any prediction that the stuff will last longer, I really do not want the cooling sytem to become troublesome.
It is almost certain that not changing the coolant is the primary cause of many gasket and radiator problems.

Mix at least 30% to get the required anti corrosion properties, 50% is fine and allows any topping up to be done with water, but any more than 55% and the coolant will not have quite the same abillity to carry heat which in some hot weather situations may be very bad for the engine. Avoid using hard water if at all possible since it can leave deposits of scale within the hottest parts of the cylinder head and degrade their cooling.

It is nearly all glycol based and can damage or stain paint, especialy in an undiluted state.

 

[rf065]

I have never seen any antifreeze with a 15 year life, the longest life stuff I have seen recently is 5 years, sold as longlife. The normal cheaper stuff has a 2 or 3 year life.

15 years is the longest I've seen from Mercedes, both Honda & Ford advise 10 years for theirs.

Also, you cannot mix ordinary with long life and should replace with like for like coolant to avoid later problems.

Russ

 

[pomm001]

I have never seen any antifreeze with a 15 year life, the longest life stuff I have seen recently is 5 years, sold as longlife. The normal cheaper stuff has a 2 or 3 year life.

What the difference is I dont know but for me the 2 year stuff is fine and does not cost as much.

It is not so much the antifreeze properties but the anti corrosion additives properties that should interest us, if the stuff stops being a corrosion preventative all manner of ills will be manifested upon the engine and radiators, for this reason I take the trouble to change it at 2 year intervals regardless of any prediction that the stuff will last longer, I really do not want the cooling sytem to become troublesome.
It is almost certain that not changing the coolant is the primary cause of many gasket and radiator problems.

Mix at least 30% to get the required anti corrosion properties, 50% is fine and allows any topping up to be done with water, but any more than 55% and the coolant will not have quite the same abillity to carry heat which in some hot weather situations may be very bad for the engine. Avoid using hard water if at all possible since it can leave deposits of scale within the hottest parts of the cylinder head and degrade their cooling.

It is nearly all glycol based and can damage or stain paint, especialy in an undiluted state.

Be very careful with anti freeze, almost all modern anti-freeze is of the OAT family ( organic acid technology ) Glycol hasnt been used for quite some time the addative pack they have is longer lasting and in general free from phosphates. The two are not compatablile and work in different ways, mixing the two would result in damage after time, put the OAT 'coolant' into a 70's engine and it would most probably eat any plastics /gasket elastomers or O rings not spec'd for OAT it comes into contact with.
Be safe, if your not sure what it is ( most OAT coolants are not blue ) drain and flush the cooling system several times and find out the spec from MB and either use theirs or a branded product to the same spec