[FIXED] Engine Coolant overflow...?

[leadfoot6]

Can anyone help with my enquiry about the correct pressure rating?

I am still not finding any from recognised sources.

Only from high performance/modified engine type websites.

The cap that has been on the car since I have owned it has no part number, but is stamped "ND" (as well as the 1.1 stamp) which I am taking a tentative guess that this stands for "NipponDenso", so it might be a legitimate part, but I have nothing else to back this up.

[leadfoot6]

Interesting thread in some ways (to me at least)



This is the bit that has me worried. I've documented in some other threads recently that I've just spent a fair amount on my TW recently and it springs to mind that Mitsubishi did actually tell me that they had replaced the radiator cap as "the bottom part had come away due to corrosion". Not that I had been noticing a loss of coolant or any other sign). The temp runs at a needles width below half as it invariably has for the last 13 years regardless of weather or driving style or air conditioning on or off or any other factor.

I had the water pump replaced so of course the coolant was dumped and replaced at the time but I can't help but wonder if the offending bottom section is indeed lurking somewhere in the cooling system (most worryingly inside the engine itself) and if this is a potential large future problem?

Seems like this may be not an uncommon problem although I'm not sure if serious enough to be worthy of the "common faults" thread .... hope not

Regards
Dec

I will respond to this later.

[leadfoot6]

I have just called Tridon Industries.

1300 362 263

They have a related cap of the correct configuration rated @ 1.1 Bar.

Part # CC16110 - the last numbers being an indication of the pressure rating.

I have been reassured by their rep that if a 1.1 cap is what I have been using with no problems, then get another one - despite the catalog suggesting that 0.9 bar is the correct part for 6G74 engines- CC1390.

My only trouble now is to be able to get to a store to pick one up or wait 2/3 days for one to arrive by post.

[leadfoot6]

More discussion in this thread:

https://www.aussiemagna.com/forums/sh...d.php?t=101975

with both 0.9 bar and 1.1 bar caps being used with success on 6g74 engines.

I was thinking that a 1.1 cap may have been a "band-aid" attempt to mask cooling system problems, but it seems that based on the above thread, what I have on my car is legitimate, so I can now look for one of this pressure rating without any worries.

Hopefully I will be able to find one not too far from me later today.

Fingers crossed that my broken cap that I have temporarily reassembled will last me for 30km or so.

[rumpfy]

I'll try to add a bit.
The formulations for coolant are based on water because of its good heat transfer properties. BUT, it boils, freezes, corrodes, and fosters algae growth.
The boiling point is adjusted by the addition of organic compounds which have a higher boiling point AND a lower freezing point. The corrosion promoting properties of water are modified by corrosion inhibitors. The main component of coolant is water.
Because the vapour pressure of water is higher than the additives, the boiling point of the water controls the boiling point of the coolant. Boiling occurs when the vapour pressure equals the atmospheric pressure. In a closed cooling system, the pressure cap allows the pressure in the cooling system to increase, and thus to increase the boiling point. For water, the boiling point versus gauge pressure is:

no pressure, 100 deg C
0.5 bar ...... 107 deg C
0.7 bar ...... 110 deg C
0.95 bar ..... 116 deg C
1.1 bar ..... 120 deg C
So the use of a 0.9 cap compared to a 1.1 cap will change the boiling point by say 6 degree C.
Because the rate of heat transfer is a function of the temperature difference between the coolant temperature and the ambient temperature, a higher coolant temperature will give more heat transfer. But the design of the cooling system will be based on the engine delivering full power at the highest ambient temperature the car will be operated in. This could be say 60 or 65 degree C. So at the worst likelihood, the use a 0.9 cap rather than a 1.1 cap will mean the engine could only deliver full power at an ambient temperature of 6 degrees C lower than the engine was designed for. The chance of this happening is remote, so the conclusion is that the use of either the 0.9 or 1.1 cap is OK.
Probably what is more important is to keep the coolant fresh because many of the corrosion properties reduce with time and vehicle use.
Hope this helps.

[leadfoot6]

Here is a thread dealing with the right pressure cap (16psi/1.1bar) for 380/6g75 engines:

https://www.aussiemagna.com/forums/sh...d.php?t=107573

This will be helpful for those who have done the 380 swap into a Magna.

As of mid-November, I will be one of them.