Coolant drain/refill

[threepot]

Hi,I intend to drain coolant and fill with new as a precaution after reading that old coolant can cause head gsk problems etc due to the corrosion. Can someone point me to a good link to explain the process,or just explain briefly where the drain/bleed screws are? Thanks 2ltr hdi 110 1999.

[keppler]

It's extremely easy, until it gets air locked lol.
To begin with, if you're going to replace the coolant then I would recommend that you also change the thermostat & gasket for good measure. Its cheap and it'll save you changing the coolant again if the old one does happen to go in the near future. Begin by openning the small drain plug at the bottom centre of the rad (this should be easy to turn with a pair of pliers), coolant will drain slowly from the plug. Then open the similiar looking plug on the top of the rad and the coolant will drain out faster.
When all the coolant has drained close up the plugs and refill new coolant via the expansion bottle. turn on the engine and let it heat up to 90 degrees and see if the coolant level drops in the expansion bottle. you will almost certainly need to top up the coolant again as the thermostat opens and the pump pushes coolant through. If after driving you notice the temp guage behaving erratically then you may have an air lock in the system. this can be sorted by openning the bleed screw located in the side of the thermostat housing. I have changed my coolant twice and thermostat once at this stage and never had a problem with airlocking but some people here say they have and by all accounts have had trouble getting rid of it. Luck of the draw i guess

[D9406]

After draining the rad I would open the bleed screw next to the bulkhead to rid the heater matrix of air, the bleed screw on the side of the thermostat and shut the bottom drain on the rad whilst leaving the top one open. Then fill the system with coolant shutting each bleed screw in turn as coolant flows from it. Next get a Coke bottle and using tape make it a tight fit into the top up resevoir bottle and fill to above the level of the resevoir and keep it filled, there is a special tool for this, start engine and run until it gets to 90 degree. Ideally run until the fan has kicked in twice, but this may not happen. Once done check your levels and job should be a good un.
An altenative to the coke bottle, put the drivers side front wheel on a ramp or high kerb. So long as the top up bottle is higher than the block either is OK as the bottle is placed quite low.

[Welly]

The water level in the expansion tank is very close to the natural water level of the heater matrix so fashioning a temporary bottle is a good idea to help make sure you displace all the air from the bleed screw. It helps to have someone holding this temp bottle as it's difficult to get it to seal on your own.

Also bear in mind that you are unlikely to get the HDi up to 90 deg's by idling the engine, in fact you'd probably stand there for two weeks waiting. Best to run it for 20 mins or so, replace the cap, go for a drive and re-check (one fully cooled!!).

Check this thread for the coolant level too....viewtopic.php?f=1&t=5318

[mjb]

I still maintain that all you need to do is raise the driver's side a couple of inches with a kerb or jack, save faffing with a pop bottle...

In fact the last couple of times I've done this (V6 and HDi90) I've not even bothered with that - just filling the reservoir to the absolute brim while on the flat is sufficient on my (shockingly perfectly level) drive

[keppler]

In fact the last couple of times I've done this (V6 and HDi90) I've not even bothered with that - just filling the reservoir to the absolute brim while on the flat is sufficient on my (shockingly perfectly level) drive

Yip have to agree with this, my hdi 110 has never needed this and my friend's hdi 90 has never needed any special treatment either. we've always just refilled ours on flat driveways filling the bottle to the top

[jasper5]

The only thing you need to do when filling the cooling system is to fill it with ALL the bleed screws undone luding the radiator one) until water floods out of each screw hole as you fill it.....This applies to any car, If I can't find any bleed screws I remove the temperature sensor before filling the system.

Run the engine with the heater pipe bleed screws undone and the blue one on the thermostat housing ( nothing much will come out of the blue one until the thermostat opens)

[Bailes1992]

I undid all the bleed screws, turned the car on then slowly filled the car up with Diisonised water.
When no more air came out the holes I let the water drop right to the bottom of the expeansion tank, did up all the bleed screws and then filled the expansion tank up with coolant/antifreeze.

Did my XUD the same way too.