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Bubbling coolant on the reservoir

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Old Jul 31st, 2021, 08:36   #11
SalvadorP
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Originally Posted by Laird Scooby View Post
It's difficult to say this without sounding sarcastic (and i'm not being) but the clue really is in the name - expansion tank. It's designed so the coolant and any air in the system expands and contracts within certain limits, controlled by the cap. There is no need to mark the coolant level, simply top up to the minimum line on the reservoir, refit the cap tightly and leave it alone. If the HG was gone, you would have a serious amount of air/liquid being forced out at a great rate and would really know it.

You're in danger of becoming an "automotive hypochondriac" and to be honest, searching online for percieved symptoms will almost always lead to the wrong conclusions. Also Google isn't necessarily the best search engine to use for this as i've found (and proved) on many occasions that the information Google holds isn't always accurate.

As i've said several times and Mark has also pointed out above, stop opening the cap when the system is hot! It's not designed for that and will lead to problems.

In the first instance, check the level with the engine cold, top up if needed to the "MIN" mark and refit the cap tightly. Next order yourself a new cap, making sure it's the same pressure rating which should be on the current cap. When you have the new cap, remove the old one when cold, top up the coolant if needed to the "MIN" mark and fit the new cap tightly.

After that check the level visually when cold and ONLY remove the cap to top up if needed. Repeated removal of the cap in between whiles will cause more problems so unless you need to remove it when cold to top up, leave it be!

In the fullness of time, yes a full flush including reverse flushing the system is a good idea but get everything on an even keel first.
It's ok. I don't know anything about car mechanics but i want to learn. Your explanation is helpful.
You are right, one can get carried away with the self diagnosis. I don't have a tendency for hypochondria, but i expect to go through a bit of a phase until i learn enough about mechanics to start connecting the dots. And i will.
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Old Jul 31st, 2021, 09:00   #12
Laird Scooby
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It's ok. I don't know anything about car mechanics but i want to learn. Your explanation is helpful.
You are right, one can get carried away with the self diagnosis. I don't have a tendency for hypochondria, but i expect to go through a bit of a phase until i learn enough about mechanics to start connecting the dots. And i will.
Going through a bit of a phase is fine but avoid the temptation of snap-diagnosis. For example, the previous owner of my car had the engine oil cooler removed because it "was leaking ATF". The real problem was he'd already bodged the spaceship bushes on the lower control arms and as a result, the steering rack was no longer in the centre when the steering wheel was in the straight ahead position. This meant the PAS was always working (not just when it's needed like normal) so the PAS fluid was boiling and bubbling up and out of the pump/reservoir (combined unit on mine) and dribbling down onto the component below it which - you've guessed it - was the engine oil cooler.
New spaceship bushes, steering rack centred, wheels aligned - no more leaks!

Took me 4 years to find a replacement oil cooler (NOS in Sweden, found courtesy of a friend on the Rover 800 forum, native Swede and he doesn't own or even like Volvos) which was probably the last new one in captivity in the world. Took another year to get the nipple (hollow nut to secure the cooler and mount the filter on) which is used from a dead engine. Just waiting for the right weather and a few other things to be right so i can get on and fit it now.

I have many other examples of incorrect snap-diagnosis provided by the previous owner of mine, thankfully all sorted now but it hopefully demonstrates the potential problems.
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Old Jul 31st, 2021, 12:01   #13
john.wigley
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Default Safety concerns

Been following the discussion 'L.S.' and would commend you as always not only for your patience, profound knowledge and sage advice, but more especially for your safety warning.

I shuddered when I read that 'SalvadorP' was happily removing the cap from his expansion tank on a hot, pressurised system with no concern for his safety. At the very least, and only in an emergency situation, I would cover the cap with a towel and remove the cap very slowly, but the best advice by far is, as you said, always to allow the engine to cool down fully before removing the cap.

It is true that we all have to start somewhere, and 'SalvadorP' is wise to tap into the font of knowledge that is available on the forum. The willingness to help and generosity of members like yourself is second to none and I am sure much appreciated by those who, like 'SalvadorP', have reason to be grateful for it.

But it is not just cooling systems that can trip up the unwary. How many people know never to go under a car supported only by a jack? I have also seen a car list markedly when the bricks supporting it in lieu of axle stands crumbled unexpectedly. 50 years ago, I had a friend who sustained serious burns to his wrist when the the metal band of his watch shorted a 6V battery to earth.

Only recently, another friend, a professional mechanic who should have known better, needed hospital treatment for an eye injury sustained when working underneath a car without suitable eye protection.

I personally have had a battery EXPLODE while on trickle charge in my garage. It threw part of the casing the length of the garage, and the spilt acid did no favours for the bench on which it was standing or the toolbox on the floor below. Not much I could do about preventing that one, but I was very glad that I was not in the garage at the time!!

Cars can be hazardous things, particularly if one is unfamiliar with any potential dangers associated with the task on which they are engaged. I believe such knowledge is at least as important as knowing how to centralise a clutch plate, for example. Thank you for pointing it out on this occasion!

Regards, John.
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Old Jul 31st, 2021, 12:38   #14
Laird Scooby
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I personally have had a battery EXPLODE while on trickle charge in my garage. It threw part of the casing the length of the garage, and the spilt acid did no favours for the bench on which it was standing or the toolbox on the floor below. Not much I could do about preventing that one, but I was very glad that I was not in the garage at the time!!


Regards, John.
Many thanks for your glowing endorsement John!

I've picked out one particular bit from your post that warrants further comment IMHO, i've known several batteries go "BANG" while on charge (one of them wasn't even on charge but trying to start the new car to which it was attached at the time) but the worst one for me was having a battery explode in my face while on charge. Luckily just the one, none of its neighbours followed!

The situation was in the generator hire industry and part of my job was looking after the batteries on the sets that hadn't been out on hire for a while. Every couple of months i would charge and rotate the batteries so there was always a battery more or less fully charged on each set. As such i had about a dozen batteries on the bench (i say bench, it was a purpose built charging bench, space for a charger and a battery in each area with many areas) that i had previously checked for SG, level etc and all just needed a top up charge. Periodically during the charge i would check the charge rates and switch off those that were fully charged (they varied in size/capacity) and i had just walked into the "charging room" when the battery nearest to me took its chance to explode.

Ended up with acid in my eyes, luckily there were several eyewash stations in there so i grabbed a couple and phoned my boss on the internal phone for help while washing my eyes out.

Had a few days off work to rest and recuperate my eyes but was seriously lucky not to have been effected worse than i was.

As you rightly point out, cars are beset with hazards, some minor, some major/near fatal. Coolant can be nasty as it scalds instantly when hot.
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