Super Wilson saves Supra engine (mine!)

So I go and pick up some bits from CW tonight and have a couple of pints down the local. Just as we're walking towards the car I disarm the alarm and he says "what's that noise". I say - "it's the alarm."

"No, the bubbling."

"Errrrr..."

"Pop the hood, it's your water boiling! Oh dear, I'm worried about that" (It was just air coming through the expansion tank pipe giving the impression it was boiling)

Oh shit oh shit oh shit...temps gauges were all fine though.

So he takes off the rad cap and it disintegrates!

Tops up the water, gets another spare rad cap from his den of spares. Bobs you Uncle, no harm done. Hardly any water missing so caught well in time.

Basically if I'd have carried on the engine would've eventually overheated having boiled away all the water. So big thanks to Super Wilson saving Supras even when off duty!

Morale of the story - if water is bubbling in your expansion tank - check your rad cap!

you drove after a 'couple' of pints? tut tut

Glad there was no damage to your engine

big up Cw tho for saving you

but why are your temp gauges saying ok? isn't that a worrie?

you drove after a 'couple' of pints? tut tut

 

 

Glad there was no damage to your engine

One pint and a shandy - I even turned down a free drink from the landlord! (Well, he gave me a bottle to take home instead )

but why are your temp gauges saying ok? isn't that a worrie?

No - because it didn't actually get that hot. No harm done.

If there was steam rising and it all felt too hot - THEN I'd have been upset. Nice cold night, plenty of cool air around it. No worries.

Nice one CW and well done Pete

I've been contemplating this on my trip to drop the mother in law off.

The water wasn't boiling, it was blowing air through the expansion tank giving the impression it was boiling (when you took it out you could hear it pushing air out). Something to do with pressure differences is my guess. The cap was probably just about holding in some pressure, but venting air off (sucked in via the rad cap?) via the expansion tube.

When we topped the radiator up there was no violent fizz or anything that you would get with cold meeting hot. This would also explain why water temp was correct on the dial.

Either way - nowt to worry about.

hey, good news!!! sounds like you owe CW a beer lol

when I first got my car I had that bubbling for a while on switch off and I never new what it was until a search on hear revealed the very same thing, a duff rad cap was the fault.

I, like you am very grateful that it was found and sorted in time before any damage was done

hey, good news!!! sounds like you owe CW a beer lol

Oh yes!...(Beers on me next time Chris)

Apparently it's a very common thing for the rad cap to go. They just break up.

So he offers a free check over of the supra with every pint ?

good deal

Good effort SW, lucky one pete!

Whether I would have noticed it *NOW*, after X pints, I don't know, always best to hit me en route to the pub ... What happens is the cooling system relies on being pressurised, if the pressure is lost nucleate boiling can occur, as some parts of the engine (head around exhaust valves for example) sees water temperatures above 100 degrees. Without pressure containment these hot spots boil the coolant and water is lost, to the expansion bottle in the case of the MKIV. You *NEED* a working rad cap to stop coolant being blown out, as later enough loss of coolant occurs to cause engine failure. Rad caps need relacing as a service item, IMO. I *alaways* check them as a part of a service, and ideally they should be repaced after perhaps 5 years. Thanks Pete, for the kind words

This man is a legend lol. I so need to find time to visit him and let him check my car over.

Does he have a bat signal I can shine intot the sky yet?

Does he have a bat signal I can shine intot the sky yet?

No, it's an Eagle Owl symbol.

Whether I would have noticed it *NOW*, after X pints, I don't know, always best to hit me en route to the pub ... What happens is the cooling system relies on being pressurised, if the pressure is lost nucleate boiling can occur, as some parts of the engine (head around exhaust valves for example) sees water temperatures above 100 degrees. Without pressure containment these hot spots boil the coolant and water is lost, to the expansion bottle in the case of the MKIV. You *NEED* a working rad cap to stop coolant being blown out, as later enough loss of coolant occurs to cause engine failure. Rad caps need relacing as a service item, IMO. I *alaways* check them as a part of a service, and ideally they should be repaced after perhaps 5 years. Thanks Pete, for the kind words

Agreed. The reason your temp gauge doesn't go high is because 100 deg. C is not that hot in an engine. The boiling point of water rises with rises in atmospheric pressure. (and conversely falls with falling atmospheric pressure) Water can be boiled at 80 or 90 deg C at high altitude where atmospheric presure is low. (saves gas on the camping stove!)

As the cooling system becomes pressurised when the engine is running, the water can heat up to well beyond 100 deg C when, for example you're stuck in traffic. The high pressure in the system means that the water won't boil. However, if your rad cap spring fails, it lets the pressure out of the system and the water boils causing coolant loss. Once you've lost some coolant, then the engine temps will rise still further and you'll see it on the gauge.

Ah - I see.

Lesson = "Look after your car", take CW for a beer regularly

nice one

Lesson = "Look after your car", take CW for a beer regularly

 

nice one

I am fully supportive of that sentiment

great thread, thanks for posting up Pete

i got home from the monthly NW meet last night to hear a strange noise (which i initially thought was someone scrambling around on the roof of the garage!) which turned out to be a large amount of bubbling going on in the expansion tank with the engine switched off :O

i daren't take the expansion tank cap off to see if it was just steam blowing through the water or the water actually boiling, but when it continued for about 10 mins i assumed it was steam blowing through

i left it to cool & when i came back to the car this morning, i found the expansion tank empty. i topped this back up to full & checked the rad cap, which came off with the little spring falling out at the same time. the water level appeared to be at the neck so i assumed this to be ok

so, my question is, should i be replacing the rad cap since the spring was not attached. a key factor i think is that my expansion tank is a small greddy replacement one that came with my front mount intercooler and the cap does not clip on very well, i.e. it could quite easily allow spits/dribbles of coolant out/steam as it was doing last night. as i'm typing this it already sounds really obvious that this needs sorting but i'm also unsure about the rad cap now i've read this thread

cheers,

wes

so, my question is, should i be replacing the rad cap since the spring was not attached?

YES!

Glad my tale has helped others.

Fit a new cap they have modded the later ones so the metal bit that corrodes and falls apart is now inert plastic.

Do you need different pressurised Rad Caps? I used to have a TRD 1.3 (??) one on mine, but Chris you thankfully found an alternative as it didn't fit my Koyo rad.

Question is, why on earth are there so many with different pressure ratings? Surely pressure in the rad can't rise with associated mods can it, or does it?

Extra pressure = more heat that can be handled...however extra pressure will put more pressure on all the parts in the cooling system, thus potentially reducing the life expectancy of your cooling system.

Ah, OK thanks Alex.