Pre-mixed Red Coolant-think my mechanic diluted it

[PhilC]

Hi,

Just had a coolant change and told my mechanic that the two 5 litre cans I supplied of coolant were pre-mixed (as stated on the can), so he could put them straight in. Got the car back and he has only used 5 litres. The Camry manual says the coolant capacity is about 9.5 litres.

Can the good folks here tell me if (i) a diluted pre-mix Toyota red coolant will harm the engine and (ii) am I right in thinking that a coolant change wil involve changing the whole 9.5 litres stated in the manual?

Many thanks,

Phil.

ps apologies for the metric measurements. Don't know what they are in imperial.

[dapqam]

You can determine if the concentration of coolant is correct by checking the specific gravity (density) of the coolant. Get a coolant tester ($3 at AutoZone, for example) and you open the radiator cap (when the car is cold, NOT HOT), pull some coolant into the tester and read the density. It will tell you if you have a proper mix. If it is diluted to much you will not have adequate freeze protection or adequate boilover protection. If you need to increase the concentration you can just drain the radiator and fill it with 100% coolant and that wil probably fix the problem. (Half the volume of the cooling system is usually in the radiator). So if the coolant concentration is 25% and you drain the radiator and refill with 100%, the concentration will go up to about 60%. Close enough.