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Expansion tank overflow/rad cap
Did some research today about the expansion tank rad caps.....

They are quite cheap ( about £5 / 6 plus vat ish ) but both types do not have the seal...the seal that seals the rad cap to the expansion tank top ( not the pressure seal or vac seal ) to stop expansion tank coolant overflow from leaking from the cap and running over the alternator, and inside the alternator.

So, I'm still using the home made seal which works a treat.

No coolant overflow contamination into the alternator now...........and the system refills automatically when cold, as the coolant is drawn back into the expansion tank as the coolant cools down.

I have been running the cooling system as normal since we have had the car and sometimes the coolant overflow has leaked into the alternator.  This was down to no upper seal and overflow tube to road.

The cooling system does not seem to loose or use coolant and has always remained just low of the "max" level plate in the expansion tank.

It still seems to run very cool for normal driving ( 70 degrees ) but does rise when more load is placed on the engine like longish uphill sections.

Will run the mod for the summer and report, but suspect I may remove the overflow tank and run the overflow hose to road.  At least the alternator does not get rained on now. Blush
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If it runs at 70 you need a new thermostat.
306 HDi Deathtrap - 130bhp / 220lbft

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