Thread: TDI COOLING SYSTEM

Originally Posted by loanrangie

Before i decide that i have probably jinxed myself, will a properly working tdi cooling system cope with either straight water or a very weak coolant mix (like 5% or less ) ?

Coolant raises the boiling point of the water. So running on water you would have it getting very hot.
Having said that I know a mechanic that after a head gasket replacement would drive for say 150kms on straight water, and then drain and refill with coolant. His reasoning was the coolant ate the head gaskets , the water idea was to condition the head gaskets first. I Don't know about that, but it worked for him.

I used what i had which was a very weak mix and had planned to do a full coolant change on the weekend but got busy, noticed some overflow when i got fuel yesterday but temp never rose and its still running great.

Running water for a week won't hurt it. Pat

Been running the mooring block on straight God's water (off my roof) for 6 months now......... no difference noticed compared with green cordial.

However......... I will be putting 4 litres of the green stuff into the system in the next week, mainly because I'll be going somewhere soon that can see -2 or lower degrees c overnight in May.

DL

Originally Posted by Roverlord off road spares

Coolant raises the boiling point of the water. So running on water you would have it getting very hot.

Coolant may have a higher boiling point than water, but there will be a lower temperature gradient between the engine block and water than between the engine block and coolant. As the temperature gauge is measuring the temperature of the water / coolant, an engine running coolant will have a lower gauge temperature, but an engine running water will have a lower block temperature. If running straight water, you will not have corrosion protection. If you do not need protection from sub-zero temperatures, it may be better to use a corrosion inhibitor without coolant.

Aaron

This was not about the co-efficiency of coolant V water, thinking that i'm still up for a head gasket since i'm getting coolant loss out of the cap but otherwise gauge temp and running wise its fine.
Never ran without coolant so not sure how well a good system will function on straight water or very weak coolant mix.

The system will cool better. The system will corrode faster. The seal on the water pump will wear faster.

Aaron

Originally Posted by Aaron IIA

The system will cool better. The system will corrode faster. The seal on the water pump will wear faster.

Aaron

The heat transfer is better but would that also make it more likely to boil ?