Hi We're going to be changing our Z32's engine coolant......in our workshop manual it says to seal the engine drain cocks with sealant (apply sealant to the drain cock threads). Does anyone know what kind of sealant is to be used? Thanks!!!
Don't worry about following FSM as it's near impossible to get at the block drain cock. Refer Tech Section, or ZedStuff cd: A-Z of overheating article by Z4Life.
When changing coolant, the most important factor is knowing that any "old" coolant left in the system will immediately contaminate(and neutralize)the new stuff, rendering it next to useless in terms of rust inhibition. To avoid this you should flush out the engine and radiator until there is only clean water remaining. Once that is achieved, you can add your new coolant(any water remaining in the system will slightly dilute the mixture, but this can be addressed by adding a little more concentrated coolant to the system).
OK, am I missing something important here? In the A-Z of overheating it has plenty of good advice about refilling the system properly but not much on emptying it. I had a quick search and the accepted wisdom seems to be to warm up the engine with the heater on full, turn off the engine but leave the ignition on then drain from either the tap or hose (I went with lower ratiator hose, much faster) and all should be good. I have done this twice now, second time with conZult plugged in to make sure it was really up to temperature (I let it get to 75 degrees) And both times I only got about 5L of coolant out. I am assuming this is just draining the radiator, I filled it up with distilled water in between goes and it came out with (slightly more diluted) coolant in it so the thermostat is definitely opening. What am I doing wrong?
Draining the system seems to be difficult. The factory manual says remove the drain plugs in the block (one an each side) and undo the tap on the bottom of the radiator. The advice is removing the drain plugs is difficult so I didn't attempt that. Instead I drained the radiator using the tap (which is real easy) and filled it with fresh water (it takes about about 3 litres, in a 10 litre system) then ran the car to open the thermostat and circulate more old coolant into the radiator, then drained the radiator again. I figure if I repeat this process 5 times or so I will get most of the old coolant out then I can put new coolant in. Sounds like you are mostly draining the radiator, but if you keep repeating the process you will eventually expel all the old coolant too.
The only way to drain it without pulling the thermostat out is open the taps in the block. They are usually frozen shut so thermostat removal is really the only way.
Hmmm I just pulled the bottom radiator hose off and flushed and reversed flushed both till it ran clear then did the change
Unless you remove the thermostat, a reverse flush wont work. The fresh water pretty much does a u-turn when it meets the water at the end of the outlet hard pipe. The water must pass thru the engine many times to clear it. Everyone should read this. http://sancarlosradiator.com/electrolysis.htm http://www.sancarlosradiator.com/VoltageDrop/education.htm
I just did mine today, this is how I did it Remove top radiator hose. Remove radiator cap Get garden hose ready Turn on the heater Start Engine. A small amount of coolant may flow out of the top engine pipe while the thermostat is closed, but not enough to cause any concern. If any more than a dribble flows out of the engine pipe, then you either have a thermostat jammed open, or a missing thermostat. Keep radiator topped up if necessary. When the thermostat opens, coolant will start to flow quickly out of the engine pipe. Don't panic , afterall, the coolant inlet for the motor is at the bottom radiator hose. Turn on the Garden hose and keep the radiator full of water. It takes about 15 minutes and the water will run clean. Remove garden hose, run the engine for about 20 seconds and then shut down. This expels enough coolant to allow the addition of coolant concentrate. Add the coolant concentrate. Reattach hoses and check the radiator level Fill as required. Replace the Radiator cap. Check the level of your overflow bottle. Check the level of your radiator every day for the first week. This won't blast your cooling system clean, although you can do this twice, and use a flushing compound the first time. This is just a simple method for completely removing an old coolant from your system so you don't contaminant one type of coolant with another, or even with old vs new coolant of the same type.
This is what I have been doing too, draining the radiator, refilling with distilled water, running the engine til it all mixes and draining again waiting for it all to go clear. Still has not happened and I have buggered one of the hose clamps on my lower radtaior hose from doing it up and undoing it too many times... This was my plan A, though slightly better thought out than my idea. The reason i went against it for plan B (see above) is that I am pretty sure the water here has all sorts of minerals in it which will make it some what corrosive to cooling systems. Ideally I would have loved a big barrel of distilled water and a pump so I could so the same thing but without the tap water. I am being pretty pedantic about how well Iflush the old coolant out of the system as Iam changing to a completely different type of coolant so don't want any cross contamination.
Indeed, however, will it completely make up for a high mineral content in the water or just reduce the damage a bit? I like the piece of mind of having demineralized water AND coolant/corrosion inhibitor, though it may be a bit over the top, I'm not completely sure so am erring on the side of safety.
Well . Depends on if you add the right coolant / water % , and if you do it right then yes it will completely stop it. The only way I can see it not working is if the radiator is rusting already and needs a new one pretty much.
OK, maybe I am being over cautious, I have always been careful to only put distilled water and coolant into my radiator.
would another method work if you could get the rear of the car high enough and drop the bottom rad hose? would that also allow for the heater core to be emptied? im looking at doing mine soon too.
I tried jacking the back of the car up as high as I could and that didn't work so if it can be done that way it would have to be higher than that.
Just follow the procedure listed by pexzed(with the further addition of turning on the heater). This will flush all the old coolant from the system.
