Draining and refilling the cooling system

[Stimpy]

Can anyone see anything wrong with my method of servicing the coolant etc, please:

What I did was:

1) Put heater switch over
2) take off one of the heater matrix bulkhead pipes.
3) Firmly attach water hose to that.
4) Ran water so it came out of the disconnected bit of pipe
5) took lid off expansion tank (mines a mk 2)
6) Put thumb over that tube so that water flowed up the coolant expansion bottle till clear and then left it running for a while
7) undid bottom hose on rad
8) take water hose from matrix thing and aim it down the rad through the bolt hole.
9) Take hose away
10) reconnect all pipes.
11) Put rainwater in rad directly through bolt hole with a third pink expensive) coolant. Did this till it got full

Then I ran out of time (2 am!!!)
So will finish tomorrow - priming and all that

One thing - I put the expansion tank lid on yet just pouring coolant into the rad hole caused coolant to come out of the overflow. I thought that was only used under pressure. It was acting just like a toilet cistern overflow if you know what I mean.

Wonder if the rad cap is knackered.

Anyone know of a halfords equivalent?

Ok - apart from that - did you believe my actions were thorough enough?

As always - thanks for any advice.

[NickA]

Don't forget to remove both block drain plugs as well.

[Arbman Al]

Don't forget to remove both block drain plugs as well.

Especially if you are changing to pink antifreeze from blue or green coloured, as the pink antifreeze will turn to jelly if mixed with the blue or green antifreeze.

[stagmuffin]

any crap you loosen and which gets suspended in the coolant is likely to get trapped behind the thermostat unless you remove it ,i always reverse flush the system .ie flush one way then the other with stat removed then flush rad and heater matrix alone at the end and dont forget as nick a said remove the plugs and root around with a wire until its freeflowing.
steve...........

[Colonel Mustard]

When I changed the coolant on mine, I removed both drain plugs and ran clean water through the radiator until it was completely clear coming out of the engine block. Although I was replacing one year old blue anti-freeze with more blue anti-freeze so I wasn't too bothered about getting everything out of the heater.

I also removed the 74 degree thermostat that had been fitted by the specialist that sold the car to me (far too cold) and fitted the correct 82 degree (for a Mk1) thermostat...with a huge improvement. Before fitting the new thermostat I drilled a tiny 1mm hole in the uppermost area of the metal of the thermostat to make absolutely sure there would be no air locks. All seems to be working well.

Chris

[Stagdad]

[QUOTE=Colonel Mustard;

Before fitting the new thermostat I drilled a tiny 1mm hole in the uppermost area of the metal of the thermostat to make absolutely sure there would be no air locks. All seems to be working well.

Chris[/QUOTE]

Most thermostats have a hole in them with a small plastic ball to act as a valve to shut of the flow when the pump is running,did yours not have this?

Cheers Steve

[Stimpy]

I know this is going to sound dim, but after looking so many times over the years I *STILL* can't find those drain plugs under the car!!

Also - with it connected to the top pipe of the heating matrix - I go between letting the water through that part of the system and then I plug it the streaming hose with my thumb which forces water up and out of the expansion tank (lid off). I thought by doing it like this I might get either side of the 'stat.

I've used red for a few changes now (which is funny 'cos when I get the thing filled at the rad it always looks greenish!).

But as far as those bolts at the bottom of the car - I'm lost with that one because I just can't find the damn things !

[Stimpy]

Actually.....

Looking at my Haynes manual it says that coolant taps are only on the early cars and that later cars require their bottom hose (rad to bottom of block) connection disconnected instead.

[ampotter]

The hex headed drain plugs fitted to Mk2s are hidden by the manifolds. You will need to jack up and support the front of the car and crawl underneath. The drain plugs require fibre washers.

[DJT]

Actually.....

Looking at my Haynes manual it says that coolant taps are only on the early cars and that later cars require their bottom hose (rad to bottom of block) connection disconnected instead.

Coolant taps were fitted to early cars, but these were changed to plain hex-head plugs somewhere around LD20000. They are in the same place as the taps. Easy to see from underneath.

[martin]

Hiya Stimpy, were you losing coolant before the change ? It sounds as if the pressure cap is shot, or, more likely, the brass collar on the expansion bottle has loosened. Martin.

[jleyton]

Easy to see from underneath.

Whilst I wouldn't disagree with Dave, I do remember struggling to find them when I first looked for them. Now I know where they are they're a doddle to pinpoint.

To help you for the first time, here's a shot from underneath with the sump removed and the offside plug circled. The nearside one is identical and in a similar place on the other side of the block. If you need help to get your bearings on this picture, the oil filter and oil pump mountings are to the left of the picture (with both pump and filter removed). The pipe across the picture is the brake pipe which is normally clipped to the subframe but that is also removed in this picture.

I looked at fitting the Mk1 drain taps to my Mk2 car but the threads were different

Good luck and cheers

Julian

DSCN1412.jpg

[Stimpy]

Whilst I wouldn't disagree with Dave, I do remember struggling to find them when I first looked for them. Now I know where they are they're a doddle to pinpoint.

To help you for the first time, here's a shot from underneath with the sump removed and the offside plug circled. The nearside one is identical and in a similar place on the other side of the block. If you need help to get your bearings on this picture, the oil filter and oil pump mountings are to the left of the picture (with both pump and filter removed). The pipe across the picture is the brake pipe which is normally clipped to the subframe but that is also removed in this picture.

I looked at fitting the Mk1 drain taps to my Mk2 car but the threads were different

Good luck and cheers

Julian

Crikey!
Thanks for going through the effort of getting that pic on there - that's got to make it easier - even for me!

Now that I have done all the work and flushed using the method I mentioned - which I did for a good hour - I am really hoping that that was thorough enough to get all the **** out. Ideally I's love to finish it now - and not have to drain and re-flush all over again. Although I'm keeping this picture for next time - definitely.

[jleyton]

You're welcome.

The only thing I'd mention is that if the system hasn't been properly flushed for a long time you can get a lot of crud build up behind those two plugs. This can be to the extent that, when you remove them, nothing comes out at first. You often have to poke around with a bit of bent wire to break up the crud - you then get a facefull of liquid

Cheers

Julian

[Stimpy]

Ok - on to caps (expansion).

With cap firmly on when I flushed the rad the stuff was coming out of a full expansion bottle - which I found odd - especially as I get a 'pssst' when I losen the cap after a journey (post cool down). When I mean 'coming out' I'm referring to the stubby pipe on the side of the bottle (top).

Also I wanted to top up the rad by closing the expansion bottle and topping up under the bolt - but it kept sinking down - telling me it was going into the bottle.

Although odd circumstances I guess the weakest link is the cap - so I need to get a new one.

There are no leaks - fortunately.

With the cap the way it is could I blame it for the temp gauge going quite up past the middle (but not in the red)?

Now - here's the oddest thing of all. My car's cooling works back to front ! What I mean is:-

At speed the temp creeps up
In traffic jams it goes down!!

Ok - I have an electric fan fitted but WTF is going on there? Fast wind of the motorway - hotter and hotter - stop at the services with car running but stationary - cooler and cooler.

HAve I got the only stag which, to bring the engine temp down, I should find the nearest traffic jam (or, more reasonably, a stop at the services).

Could that be blamed on the cap? The pump? Anything else?

As usual - thanks to everyone. This is got to be the best voluntary site where people are keen to help. Just wished I knew enough to advise others. Although I do revisit my odder posts to 'tidy up' and explain the solutions - which I do hope are informative.

Cheers