Buzz,
By heater core, is that the same as the heater matrix in the rave?.. In the dash.
Special flush required to flush the Dexcool from the heater core, or does it flush it affective enough with the regular flush procedure? Just a little nervous about leaving any remnants of the Dexcool behind
B

 

heater core = heater matrix. Because it is so small, just remove hoses from engine and flush first one direction, then the reverse direction. Garden hose should be good, you'll do a final flush of whole system once back together with distilled water before re-fill. Owners with external thermostats like the D2 shold plan on new stat as well, flush will clog small holes used to keep stat operating.

 

Great write-up! Thanks!

I just did this and the only bit of advice I would add is to use vice-grips instead of a c-channel pliers (like I did at first) to remove and reinstall the hose clamps. The vice-grips allow you to lock the hose clamps in the "open" position, making it much easier to maneuver the clamps around.

 

My thermostat had its plastic "lips" eaten away and was leaking about 6 months ago... I replaced the thermostat with one from the dealer.
When doing the flush as described, what are the odds it gets clogged up and rendered no good?
Should I have an extra one on hand before doing the flush?
Is there a way to bypass the thermostat when flushing?
Am I over thinking this one?

Thanks
Brett

 

You are wise to consider that a reverse flush would force gunk toward the thermostat and those tiny holes, or perhaps break some gunk loose to be circulated. In drawing, if hose 15 and 12 are removed, and you are just flushing radiator, not so much chance. If replacing stat is considered, there is a model available that runs at 6-10 degrees cooler. see http://www.landroversonly.com/forums/420259-post6.html, Motorad 439-180

 

I usually remove the thermostat when I flush the cooling system. I clean out the thermostat separately. I tend to remove just about all of the hoses and force water through each part individually. I use a hose attachment (I don't remember what it's called, but it looks kind of like a tiny version of the old fire hose nozzles) to get into the small hoses like the heater core and the reservoir hoses. It helps to have the heater cut on and the electric on, so nothing mechanical stops or slows the flow of the water through the heater core. When I clean out the thermostat, I check it for damage, wear, and blockage.

I've never removed anything to get to the thermostat (fan or cover).

Be careful removing hoses. If you don't know how to do it without damaging the hose, don't even try to do it the way I do unless you're going to replace the hoses. I generally don't use any tools to remove a hose, and if I do, it's only to give it a little twist to break it free, then I do the rest by hand.

I also have one hose that I spliced a water hose attachment to. It is built to stay on a car, but I prefer to remove it and use it on whatever car I want to flush. If I don't think I need to do a real thorough flush, I just attach that hose to the heater core line and attach a water hose, then remove the drain plug and run the car while the water hose pumps clean water in. It's not as good as taking all of the hoses out, but it gets the job done on cars that look like they have a clean system already. Because of the way the thermostat is set up in this vehicle, I don't like to do it this way in the Discovery.

Either way, I finish it off by running compressed air through the system in order to get the tap water out before refilling with coolant.

 

re: heater cut on and the electric on, so nothing mechanical stops or slows the flow of the water

Would thimk that would be needed on early versions of D1, but later versions and the D2 have no valves in coolant flow to heater core, warm air is controlled by duct flaps.

 

I just do that with any car I'm flushing, because I don't know if it's necessary or not on every vehicle I work on, and I know it won't hurt anything to do it on any vehicle. But good to know.