Struggling with 3B frost plugs - HELP

[nikalex]

Good Day.
I am having a bugger of a time replacing a slightly leaking frost plug on my 3B that is in my '85 BJ73. It is the #1 lower frost plug and it shows no sign of corrosion at all. The old one looks perfect except for it had a slight drip around the edge. I've recently replaced the rad with a 4 core, the water pump, thermostat, hoses and coolant and of course all gaskets. The old coolant looked OK and was probably 4 years old.
I took the old frost plug out and measured it at 35.0mm. I went to Lordco to buy a US made 35mm plugs and fought with it for a while til I measured it at 35.5mm. This seems a bit over size for me to bash into the side of my block. I tried the next size down, a strange 34.3mm and it nearly slipped into the block, it was so loose. A 1-3/8" frost plug measured at 35.25mm and I was able to bash it in. I didn't remove the injection pump for this, just the return line and both batteries.
Now I have discovered a very small drip at my newly installed 1-3/8" frost plug.
What did I do wrong?
Regards, Roman

 

[UpsideDown]

Here are a few quick suggestions before I head to a meeting:

Check the bore that the plug came out of. Use some fine emery cloth to clean up the surfaces and clean the area well.

The new plug must be installed totally straight and square. There are tools for this task and they are not expensive.

You can use some aircraft gasket sealant (the brown pooh kind of stuff - it's really gooey) on the new plug when setting in place.

Make absolutley sure you clean out any stop leak or other crud from your cooling system. Use NOT less than a 50/50 mixture of NEW coolant and DISTILLED water. A 50/50 mix will test to around -36C (a 70/30 mix is even better).

Have to run...


hth,


John

 

[nikalex]

Thanks for the advice.
I didn't use any sealant. I will try this next time as I still have a very slight weeping from around the new frost plug.
At least the frost plug that came out wasn't corroded at all.

However I did originally use regular tap water to mix my 50/50 up when I rebuilt my cooiling system a month ago. Is this a huge mistake?
I have since topped it up with 6 or so litres of premixed, overppriced stuff from Can Tire.

Someone warned me about the water pump gasket that can leak and make it appear that #1 frost plug is weeping. Is this common?
Also I didn't use any gasket sealant on the new waterpump to block gasket.

I will wait for better weather to change it out again.

Thanks,
Roman

 

[crushers]

yes, the water pump gasket can leak making it look like the coolant is coming from somewhere else.
beg, borrow or buy a coolant pressure tester and pump up to 1lbs pressure, this will show where the leak is coming from...

 

[UpsideDown]

Hi Roman;

Really, the frost plugs should seal adequately without sealant, but using Aircraft sealant does give some advantage.

Having a seeping frost plug can cause quite severe overheating issues if it does not allow your system to come up to pressure and you're losing coolant.

For the Vancouver area, using distilled water is not a 100% requirement, but is very adviseable - I do see many plugged radiator coming in and I operate on Vancouver Island in an area where the water is as soft of even more soft than Vancouver. Mind you, many of these rads have not been properly serviced over the lifespan of the vehicle...

The water pump seal and gasket can leak. If you cleaned the surfaces properly and degreased them properly, the supplied (impregnated) gasket is totally adequate.

On the 3B, leaks from the water pump gasket and seal can look like they are coming from different areas due to coolant migration along the surfaces of the engine.


hth, and ymmv

~John

 

[UpsideDown]

[...snip...] a coolant pressure tester and pump up to 1lbs pressure, this will show where the leak is coming from...

I think he intended to write 10 or 12 lbs.

 

[nikalex]

Thanks for the information everyone.
I am second guessing myself on the water pump gasket that I used now. I thought I was pretty meticulous. It appeared to be a thin metal gasket to me. The gasket and pump were Toyota OEM. I will verify the gasket with the old one at home. The new gasket didn't have anything impregnated on it and I elected not to use any gasket sealant on it either as the metal surfaces on the engine were clean and smooth and the old metal gasket came off easily. It didn't appear to have any old sealant on it either. The water pump (and all other parts) seemed to be of the best quality to me. I purchased all the parts through Dan at 4WheelAuto.

I seem to be building up pressure OK based on the hoses being firm to the squeeze AND my temperature is rock steady at a bit less than half way up the guage. It is a very, very small leak so I think I'm going to watch it and see what happens.
I know my temperature guage works as it was going up and down while I was filling the engine back up with coolant in cycles.
I know my expansion tank works as it should because I took it apart and cleaned it and observed it sucking back coolant into the cooling system as everything was cooling down.
The nipple into the pressure cap / thermostat cover was blocked solid and I cleaned it out months ago.

Here's how I filled my cooling system (for better or worse)

Top up the coolant at the pressure cap above the closed thermostat.
Run engine to operating temperature.
Let it cool.
Open cap.
Top up.
Repeat until system is full, which took about 4 cycles.

This is the only way I knew how with this engine. Surely there must be a better way!

I will borrow a pressure tester if I can find one.

Thanks,
Roman