Morris Minor Owners Club

Following on from my other problems today, I think I need some help with my radiator.

I've decided to flush the system and replace with new coolant and water. I started off by undoing the drain bolt on the engine block but only a few dribbles came out. I've had a good poke around but even with a full rad and a few more pokes only a few dribbles come out.

Also, after flushing the system it seems that I can only squeeze 3 litres of water/coolant back in to the system. My manual says that it holds 5 litres.

Can somebody tell me what's gone wrong.

Many thanks
Bretta

The heater cannot be drained because it is lower than the feed pipes so you need to flush through the block and remove heater pipes from back of engine to flush it through - This will of course still retain water so that would account for an amount of your "missing" fluid....

Ah, that makes sense, thank you.

Should I worry about no water coming out of the engine block drain bolt?

thanks again.

Bretta wrote:Should I worry about no water coming out of the engine block drain bolt?

It's not ideal because it probably means the back of the water jacket is silted up. When mine did that I connected a hosepipe to the heater valve on the back of the head and turned the water on (just a trickle at first), then put my thumb over the disconnected heater hose while poking a bit of stiff wire around in the block drain hole. Once it started pouring out freely I opened the tap fully and left it running until the water ran clear.

Hi there,

It's already getting a bit complicated for me, sorry to be a dunce. Is this where you mean for the heater valve and where I should place the hosepipe?

regards
Bretta

You have a natural talent and have found the right thing 1st go .
If you take the bottom hose off the system will drain from a lower point but try the hose pipe thing first.

great, much thanks.

That's right, if you disconnect the heater hose from the valve you can fit a hosepipe to the valve instead. Then when you turn the hose on, water will come spurting out of the disconnected heater hose. Put your thumb over it and the hosepipe will pressurise the system and hopefully blow the silt out of the water jacket drain hole (assisted by the poking with the stiff wire). Be warned that you, the engine bay, and the drive will probably get soaked with rusty water in the process!

thanks Alex, you've been a massive help.

regards
Bretta

Some have used drain cleaner in the rad as a flushing agent. Don't leave it in there too long - and flush it all out afterwards. And yes - you need to get a good flow of water going out of that drain plug hole - so much poking with bent wire required!

bmcecosse wrote:Some have used drain cleaner in the rad as a flushing agent. Don't leave it in there too long - and flush it all out afterwards. And yes - you need to get a good flow of water going out of that drain plug hole - so much poking with bent wire required!

A good poking it will get.

thanks again.

I used washing machine descaler in mine which has to be gentler than drain cleaner. I was astonished at the amount of muck and rust that came out. Did it twice as it had a slight tendency to overheat, made a huge improvement. You can't flush it enough really, just persist with it and it will run clear eventually.

What's in 'washing machine descaler' ??

No idea but it did the trick. Same as kettle descaler I bet. Poured it in, went for as quick spin, rinsed, another spin, rinse, used the 88 degree programme

OK, well I followed the instructions for flushing out the system by the garden hose pipe method. After turning on the water and putting my thumb over the disconnected heater hose I sprung a leak and got soaked via the rad overflow pipe. Put my thumb over that too and then sprung another leak on a small little hose right by the rad fan.

Is that little hose called the "by-pass" hose or the "top rad hose", as I'll need to order a new one.

Also can I have some suggestions on what additives i can add to clear this blockage (a few have been mentioned already), and how I go about doing this op. Do I fill up with whatever cleaner and go for a run in the car, just let the car tick over or just leave to do it's stuff without running the engine and flush system again?

Thanks again for everyone's patience.
kind regards

BTW. Still no water (a few dribbles) coming from the engine block drain bolt
Bretta

There are products like Holts speedflush which you just put in and go for a short drive then flush, I tried this but it wasn't strong enough. Hence the washing machine descaler. My car had been stood for a while when I bought it and there was no antifreeze in it, which is not good as antifreeze inhibits corrosion. Maybe yours too as it seems all bunged up? If you do decide to use a product which isn't specifically designed for a car engine I wouldn't leave it in overnight, I reckoned that the descaler would be ok as washing machines have rubber hoses and seals too, like cars, so hopefully the product would not be too vicious.

That tiny little hose about an inch or so long and probably corrugated is the bypass hose and the one between the rad and the thermostat housing is the top hose.

It sounds like you need many flushes, just persevere and I am sure you will get there. There's still a bit of rust in mine so will do it again, and yours sounds worse so don't expect to do it in one go. Keep undoing the bottom hose and draining the lot out then refill and try again. Are you getting lots of rusty water coming out?

Hi there,

no, not getting any rusty water at all, and even the first lot I flushed didn't seem to be that dirty.

regards
Bretta

If you are 2 litres down on your water capacity and all furred/silted up I would have expected the car to overheat quite a bit, does it? Is the car in regular use? Heater work ok?

Car is used about three times a week, I've owned it since April and haven't gone on any long spins yet, plus I haven't owned it in the hot months. Heater seems to work fine too.

regards
Bretta

I think it's unlikely then that you are 2 litres down on your water capacity. Maybe try the speedflush or a similar product and carry a jerrycan of water with you for a while until any problems become apparant? If you have a big loss of coolant or a serious reduction in capacity due to silt you would be overheating pretty soon, I mean a few miles even in April.
If you don't know the history of the car check all the hoses and clips are ok and not perished and replace the thermostat and possibly the radiator cap, they are cheap.