Cavitating water pump. ST205

[MAGN1T]

It is aftermarket OEM replacement (plastic tanks), bought locally, core and tanks looks exactly like original (even inside, looking through filler). .

You haven't even asked yourself why the original one split?

Surely a faulty headgasket couldn't have done it just like those at pick a part?

Steve

[cat007]

I'm confused

How on earth could the outlet be collapsing?

I've seen the outlet collapse on mine only because my radiator cap was stuffed and after everything cooled down the engine couldn't suck any water in from the radiator.

And yeah, for a hose to collapse - without the temp changing, the water has to have gone somewhere....or you've got super soft top hoses that are swelling heaps!

[sergei]

It is aftermarket OEM replacement (plastic tanks), bought locally, core and tanks looks exactly like original (even inside, looking through filler). .

You haven't even asked yourself why the original one split?

Surely a faulty headgasket couldn't have done it just like those at pick a part?

Steve

Man, surely you are a troll.

If you paid attention in Chemistry at school you would understand why radiators split over the time.

Are you suggesting that 100,000kms is a life time of a head gasket on a toyota with proper glycol mix?

Radiator outlet, water pump inlet.
Again, for those who did not read, this problem only happened during/straight after time on track. Every thing was very, very hot.
The inlet on the radiator was pressurised. There was usual boil from turbo (I guess it get over ~120'C there), so there was slight bubbling in the overflow bottle. I admit I drove it very hard, pulled in the pits (due to surging on corners), instead perhaps I should've done a cool down lap (or two). I simply did not expect it to get so hot in turbo area.

[MAGN1T]

Man, surely you are a troll.

If you paid attention in Chemistry at school you would understand why radiators split over the time.

Come on then, explain.

I've done a bit of chemistry, I've also seen brass radiators split the solder of the top tank (3 times for the same radiator) and also seen lots of modern crimped tanks split. It's physics that does it.


Steve

[cat007]

Come on then, explain.

I've done a bit of chemistry, I've also seen brass radiators split the solder of the top tank (3 times for the same radiator) and also seen lots of modern crimped tanks split. It's physics that does it.


Steve

That's not going to help sort the issue at hand which I'm genuinely curious about....

[sergei]

Man, surely you are a troll.

If you paid attention in Chemistry at school you would understand why radiators split over the time.

Come on then, explain.

I've done a bit of chemistry, I've also seen brass radiators split the solder of the top tank (3 times for the same radiator) and also seen lots of modern crimped tanks split. It's physics that does it.


Steve

Plastic deteriorates due to temperature,pressure and chemically active environment (ethylene glycol slowly decomposes from as low as 60'C to various active organic compounds like glyoxal, glycol acid, glyoxylic acid, formic acid, oxalic acid, glycolaldehyde, formaldehyde, etc.).

If it was just pure mechanical failure, then both of the top and bottom tanks would fail at similar rate. While in reality top tank is always cracking in the middle, and in most cases it is not in the place where the radiator hose pulls the most, while bottom tank looks like new.

My theory is that most of the plastic affecting substances are lighter than ethylene glycol mix and rise to the top and are absorbed in plastic (and top is hotter). This absorption weakens due to substances depolymerising and/or affecting bonds otherwise, combined with fatigue from thermal stress, pressure and vibration, form micro-cracks that develop in fully blown split top tank. If you look closely on a split tank it is not a single definite split, but thousands and thousand smaller cracks, and whole plastic is completely deteriorated.

[matt dunn]

I admit I drove it very hard, pulled in the pits (due to surging on corners), instead perhaps I should've done a cool down lap (or two). I simply did not expect it to get so hot in turbo area.

You may find that due to the hard running and then sitting idleing that it boiled in hot spots in the system causing air?

I had real problems with my car when i went 1800cc,
and in the end it was as simple as the overflow bottle was not large enough in capacity, and it would overflow it under racing condition then suck air back in,
and a larger overflow bottle fixed it. I needed one that is about 2L in capacity.

[sergei]

I admit I drove it very hard, pulled in the pits (due to surging on corners), instead perhaps I should've done a cool down lap (or two). I simply did not expect it to get so hot in turbo area.

You may find that due to the hard running and then sitting idleing that it boiled in hot spots in the system causing air?

I had real problems with my car when i went 1800cc,
and in the end it was as simple as the overflow bottle was not large enough in capacity, and it would overflow it under racing condition then suck air back in,
and a larger overflow bottle fixed it. I needed one that is about 2L in capacity.

That could be it, I noticed that the turbo was so hot that the coolant inside it was boiling hard.

[MAGN1T]

That's not going to help sort the issue at hand which I'm genuinely curious about....

Of course it is, It's called cause and effect.
The original one failed, that was the effect.

So what was the cause?

If it was just pure mechanical failure, then both of the top and bottom tanks would fail at similar rate. While in reality top tank is always cracking in the middle, and in most cases it is not in the place where the radiator hose pulls the most, while bottom tank looks like new.

My theory is that most of the plastic affecting substances are lighter than ethylene glycol mix and rise to the top and are absorbed in plastic (and top is hotter). .

Yea whatever?

The top tank is always hotter than the bottom one. Hot plastic fails before cold plastic.
Due to too much pressure inside.

You may find that due to the hard running and then sitting idleing that it boiled in hot spots in the system causing air?

I had real problems with my car when i went 1800cc,
and in the end it was as simple as the overflow bottle was not large enough in capacity, and it would overflow it under racing condition then suck air back in,
and a larger overflow bottle fixed it. I needed one that is about 2L in capacity.

Sounds like yours is still broken.

That could be it, I noticed that the turbo was so hot that the coolant inside it was boiling hard.

Never had turbos on any car of mine cause the water to boil.

No doubt I've owned turbos for far longer than anyone else on here.



And to think that something as simple as using a pressure gauge on the cooling system removes any guesswork.
Must be too hard?



Same applies to any motor, you can make more and more power until you find the weakest link. So if you overcome detonation, overcome fuelling issues, the next weakest link is the gasket. They all leak but as to how much they leak is dependant on how hard you push it. There's nothing simpler really.
Look at "real" dragsters. They pull the heads after each run and fit new gaskets.
So what for, what's the point?

Steve

[Crampy]

Whoa, after reading that I think I've blown my headgasket

[JustinSpiderholden]

Whoa, after reading that I think I've blown my headgasket

I hope this guys not a real mechanic

customer
"my car is not running correct"

MAGN1T
"thats will be a blow headgaskit"

[evil_si]

check the water pump suction clamps are tight, as well as the bypass oring,

i have seen a couple of waterpumps suck air thru the hose clamp joins,
causing cavitation due to the air being sucked in,
some blow water out the radiator over flow and bubble in the top tank and can tirck people into believing its a bhg,

be aware there may not be an actual external leak,

[fivebob]

Never had turbos on any car of mine cause the water to boil.

Then you admit to a lack of experience in these matters then.

FYI it's quite common for water to boil in the jacket of a water cooled turbo, due to all the heat soak and the water is not moving when the engine is idling or shut off. SW20s do it all the time, due to the lack of airflow in the engine bay they heat up a bit more that ST185/205/215s, but after a hard run they do it too.

No doubt I've owned turbos for far longer than anyone else on here.

Care to take a bet on that?

Look at "real" dragsters. They pull the heads after each run and fit new gaskets.

Are you sure on that, or do they just anneal the copper gasket and reuse it later

So what for, what's the point?

To match the set of pistons that they've just put in so they get the CR exactly where they want it

[iOnic]

If you take everything Steve says seriously you'll conclude that anything that can possibly go wrong with a car can somehow be narrowed down to a blown headgasket....

[Adamal]

If you take everything Steve says seriously you'll conclude that anything that can possibly go wrong with a car can somehow be narrowed down to a blown headgasket....

Now thats what I call LOLgic!

[Alex B]

Yuh tail lights out due to incorrect stereo install is also a cause of BHG.

[Dell'Orto]

Finally worked out the cause of my car idling high all this time, its definately a BHG.

[79rolla]

si it was water pump inlet hoes/ radiator outlet that colaped?

i would say that because o being hot the hoes was softer then usual and there was enough of a resistance in the radiator core

it has already been established that there is air in the system

if not radiator there could be enough of a resistance caused by the thermostat perhaps?

radiator splitting is perfectly normal with plastic tanks due to perishing. mr BHG, yes on alot of cars a split radiator can often mean BHG but usually because people don't realise the radiator id leaking untill the motor gets hot due to lack of water, witch caused a BHG..

PS fluid leaking will probably be from it splashing around due to harsh cornering/breaking ect and the li not being sealed

any other questions?

and my ute idols high due to bad fueling setup after mechanical pump died and was replaced with electric pump, just replaced head gasket a few months ago and i still have the issue, do you think its a BHG?

sorry just couldn't resist jumping on the bandwagon..

[cat007]

MAGN1T - have you ONLY worked on (or at least destroyed) 7M's? Because you realize that there are other engines out tehre that don't blow HG's left right and center....

[matt dunn]

and a larger overflow bottle fixed it. I needed one that is about 2L in capacity.

Sounds like yours is still broken.

Yes must still be broken that's why it has been fine for the last two years of racing, and why when we were at ruapuna racing on a near 30deg day,
my car was one of one 1/3 of cars that did not have overheating issues.

I presumes that means you are going to say 2/3 of the cars I raced against all had blown head gaskets too?