Morris Minor Owners Club

How are you measuring the temperature?

I us an infrared gun and measure on the head at the thermostat housing and on the head at the heater outlet.

Chris

svenedin wrote: ↑Wed Sep 10, 2025 8:54 pm

cswagon1 wrote: ↑Wed Sep 10, 2025 8:42 pm May I ask what you managed to use to dig the sludge out as I have tried all sorts, unsuccessfully, and
I've personally run out of ideas.

Many thanks

Graham.

This has been discussed on here many times and if you search the forum you should find lots of ideas.

Personally, I used a combination of long screwdrivers and coat hanger wire. Phil has posted pictures of a cutaway of the block. It helps to have seen this so that you can visualise in your mind what you are poking at and bend your coat hanger wire to suit.

viewtopic.php?p=636733&hilit=unblocking+drain#p636733

viewtopic.php?p=618388&hilit=engine+block+drain#p618388

Stephen

Many thanks indeed for this information and the links. I have only owned my van for a few weeks and just did the usual preliminary checks and fluid changes when I first got it and that was when I noticed that the drain tap was doing nothing.
I managed to clear the tap on the bench but couldn't make any headway into the block.
I will revisit this later as I have spent the last week or so cutting out sections of chassis and welding new metal in and I've probably got another few days to go.
Apologies to the O.P for high jacking your post.

Regards

Graham.

cswagon1 wrote: ↑Thu Sep 11, 2025 10:56 am

svenedin wrote: ↑Wed Sep 10, 2025 8:54 pm

cswagon1 wrote: ↑Wed Sep 10, 2025 8:42 pm May I ask what you managed to use to dig the sludge out as I have tried all sorts, unsuccessfully, and
I've personally run out of ideas.

Many thanks

Graham.

This has been discussed on here many times and if you search the forum you should find lots of ideas.

Personally, I used a combination of long screwdrivers and coat hanger wire. Phil has posted pictures of a cutaway of the block. It helps to have seen this so that you can visualise in your mind what you are poking at and bend your coat hanger wire to suit.

viewtopic.php?p=636733&hilit=unblocking+drain#p636733

viewtopic.php?p=618388&hilit=engine+block+drain#p618388

Stephen

Many thanks indeed for this information and the links. I have only owned my van for a few weeks and just did the usual preliminary checks and fluid changes when I first got it and that was when I noticed that the drain tap was doing nothing.
I managed to clear the tap on the bench but couldn't make any headway into the block.
I will revisit this later as I have spent the last week or so cutting out sections of chassis and welding new metal in and I've probably got another few days to go.
Apologies to the O.P for high jacking your post.

Regards

Graham.

You're welcome. It's tedious but worth doing because then you can do a really good flush. If you can get at least partial flow using physical means then the rest can be done with citric acid.

Stephen

After reading the replies at lunch time I decided to have a short break from my chassis welding and try another approach at the crud in the drain port.
This time I utilised the drain tap that I had freed off and pushed a thin plastic pipe into the outlet hole.
At the other end of the pipe I attached a very small funnel and screwed the tap back into the block.
I then mixed a small quantity of fairly strong citric acid and poured it into the funnel until it reached the top.
I'm hoping this may attack the blockage from the outside in but we shall see.
The welding continues and I shall keep you updated.

Graham.

cswagon1 wrote: ↑Thu Sep 11, 2025 5:24 pm After reading the replies at lunch time I decided to have a short break from my chassis welding and try another approach at the crud in the drain port.
This time I utilised the drain tap that I had freed off and pushed a thin plastic pipe into the outlet hole.
At the other end of the pipe I attached a very small funnel and screwed the tap back into the block.
I then mixed a small quantity of fairly strong citric acid and poured it into the funnel until it reached the top.
I'm hoping this may attack the blockage from the outside in but we shall see.
The welding continues and I shall keep you updated.

Graham.

DSCF0008.JPG

Ingenious! I did something similar to that and it did work. As the citric acid solution is cold it will be rather slow so be patient. Good luck!

Stephen

Thank you Stephen, and don't worry, I have plenty of welding to keep me occupied.

Graham.

Hi Graham
As others have done I used various fine screw drivers and seal picks and moving on to a wire coat hanger with various bends to get as far around the block as possible. I then used a citric acid solution for around a week, I have since flushed several times and scraped with screwdrivers and wire again, I then finally flushed with clean water again and added antifreeze. I have again taken her out for a good run today with no signs of overheating, only down side is the heaters are now a lot cooler where they used to be like toast.

Thank you Jonessa,I am still leaving it to ferment at the moment but I have also taken the pipe off of the heater valve now, and as the radiator is out and the block is as empty as it can be, I have also added a strong solution via a short length of hose directly into the valve and hopefully that will attack it from both sides.
I've still got a small amount of welding to do in one wheel arch and then I'll check on progress and report back.
I'm glad you managed to sort yours out.

Graham.

I rigged this up to flush my block, you can run the engine up to operating temperature.
Regards Win

Is that just pumping cold water around the block and then out back into the plastic container?

The water is heated when you run the engine.

Thank you for that Win, that's a great idea.
Unfortunately, all my efforts so far have only resulted in 2 of the 3 core plugs on the side started leaking so
I've hooked those out and let the water solution drain, and tomorrow I'll whip the distributor out and take out the third one.
Would I be right in thinking there are more around the back please?
If there are I'll probably leave the citric acid method alone for a while as I'm not too keen at taking the engine out at the moment.

Thanks again

Graham.

cswagon1 wrote: ↑Sun Sep 14, 2025 6:55 pm
Would I be right in thinking there are more around the back please?

Yes there is one on the back that requires the engine & gearbox separating, with clutch, flywheel and gearbox mounting plate removed.
Right here.....
I did the one on mine while it was out for the clutch....

How often do core plugs need replacing? I've never done mine.

ndevans wrote: ↑Mon Sep 15, 2025 9:55 am How often do core plugs need replacing? I've never done mine.

I think it just depends on the use of the engine and what coolant may have been used, remembering that originally many used plain water in the summer.
Except for the rear one, the others are easy enough to change when they give signs of failing.

My car had a Gold Seal engine that was fitted around 1998/9, but I've no idea how old it was when fitted.
I also had no idea as to true mileage of the car as the odometer had been broken for several years.

When I got him (2017) there was slight weeping from 2 plugs, just enough to leave a rusty mark on the paint, so I changed them.
I wasn't going to risk the rear one being an unknown so when the engine came out for other work, I changed that one too.
It didn't look to be in bad condition, but I wanted to know it was 'new' and took exceptional care to make sure it was a good fit.

ndevans wrote: ↑Mon Sep 15, 2025 9:55 am How often do core plugs need replacing? I've never done mine.

I would only replace if there are signs of a leakage, damage, or one falls out - like one of mine did on the road once!
Fortunately, it was an easily accessible one on the side......

Guess I'd better get some spares in!

Many thanks for your reply and picture, I thought that might be the case.
I'm sure mine only started leaking because of the citric acid but I'm hopeful that the rear one
isn't affected, and like the 3rd one behind the distributor, stays dry.
I've taken the dizzy out this morning but there's no sign of water seepage from the core plug so
I'm just overhauling it and going to put it back for now.
The knurled nut on the vacuum end is stuck solid and probably hasn't been turned in a while so
that's soaking in plus gas while I have my lunch.

Many thanks again Geoberni

Graham.

ndevans wrote: ↑Mon Sep 15, 2025 11:49 am Guess I'd better get some spares in!

Yes, good idea. I keep a couple in my boot after the incident on a dual carriageway. Not having any spare core plugs at the time, I was reduced to calling RAC, who ingeniously blocked up the plug hole with a spiral of some sort of goo that went hard so that I could drive home and repair properly once I had obtained some spare plugs.