Suggestions please? Weird overheating!

[Doug G]

Sounds like it

http://www.minispares.com/product/Class ... 0catalogue

DRAIN PLUG ENGINE BLOCK REAR WATER DRAIN OFF fitted to the rear of engine blocks to drain out water these are now obsolete from Rover but available from us ( www.minispares.com ).

[Doug G]

From another forum:

My son's 67 mustang was getting hot even after a new 4 core aluminum rad AND an oil cooler AND a tranny cooler. A friend said the passages had to be clogged. He told me to drain the system, add a gallon of white vinegar and then refill, run the car for 20 minutes after it warmed up or it started to overheat then shut off and leave it overnight. Then drain again and flush with water. It worked perfectly and it doesn't hit 190 even in the hottest months in heavy traffic now. I'm a believer.

Drain & flush cooling system, use "CLR" in 20:1 ratio (1 qt per 5 gallon water) or stronger. Get cooling system up to temp and top off. drive normal for 2-3 weeks then flush the CLR and rinse with a vinegar water mix, then fresh water then refill with coolant. this gets crap you cannot scrape with freeze pulgs pulled.

When I put a new water pump and freeze plugs in my old F1, I let the hose run through the engine while I dislodged a LOT of crap using an old dipstick. Then, vineger treatment and if you put a piece of nylon (panty hose) in the top radiator hose it'll catch lots of what's left.

Use a presure washer and stick in every hole. I did this to a block that I got back from a wash and a bake at a engine rebuilder and got a whloe lot of extra crap out.

The only way you will ever get the scale / rust out of the block is to have it dipped in a commercial cleaning bath. If you have been poking round in the block you will probably do more harm than good, as the scale you have disturbed will now be carried into the radiator. It might be wise to put a stocking in the upper radiator hose to capture any scale before you run the engine again; leave it there a 50 miles or so then remove and you may be surprised at whats in it.

A word of caution, you are disturbing many years accumulation of buildup and corrosion.

If you are doing this with the engine in situ, no matter how hard you try, you will not clear all of it from the engine, so expect the residue to be circulating around the coolant system for months to come. Most of this will ultimately lodge in the radiator and before you know it you will have overheating problems.

To avoid this problem ensure you install a filter at the radiator inlet and ensure you clear it regularly ( one of her stockings will do ); you will be amazed how long this rubbish remains in circulation.

[Stromfirth]

Thanks for the information - working on it! Will let you know how we get on.

[Doug G]

The engine in my Mini Moke does got have a drain plug in the location on the sketch above.

I am going to have to try the vinegar solution (pun intended).

[Wally2]

Hi Doug,
If its not got a plug there, has it got a tap? as per item 25 on your previous diagram? It should have one or the other I would have thought?
Chris

[Doug G]

Hi Doug,
If its not got a plug there, has it got a tap? as per item 25 on your previous diagram? It should have one or the other I would have thought?
Chris

No, all very conspicious in their absence.

[Wally2]

Doug,
What engine do you have in your Moke? Its not a Honda engine is it?
Chris

[Doug G]

Doug,
What engine do you have in your Moke? Its not a Honda engine is it?
Chris

No, I believe it is an A series.
During repairs

[Doug G]

Here is a picture of the engine when it was out of the Mini Moke being cleaned and readied for painting

[Wally2]

Hi Doug,
Cannot see pics ?
Chris

[Tim]

That's an A+ Doug, from a later model Mini.

Tim

[Doug G]

So where is the water drain plug?

[Wally2]

hi Doug,
Can you put the pics on the gallery, then I may be able to see them.
Cheers
Chris

[Tim]

A bit of googling suggests that the drain plug was deleted at some stage during A+ development, some have them some don't. It took the factory 40 years to realise that they aren't much use. Initially they had a nice little brass tap in there, then a plug, then gone.

Tim

[Nigel(no top)Sykes]

I guess if you want to drain your cooling system Doug, you will have to undo the bottom end of the bottom radiator hose ... That's why you made sure the jubilee clip had the screw towards the back of the engine bay and facing upwards !! Didn't you ?