Cavitating water pump. ST205

[sergei]

Took out my ST205 GT4 (stock standard) to track day (Hampton Downs).
Had great fun, until it started to surge because of low fuel.
So here I pull in pits only to discover two things:
1) P/S fluid is all over the place (was not over filled)
2) Noise coming out waterpump if revved up (only on sudden increase of RPMs).
3) during 2)water inlet hose on the block (waterpump end) would collapse.

I assume noise is because of cavitation from water pump, due to hose collapsing from heat/water pump suction?

It was happening while system was pressurised as well which would mean that water pump had to work against 2 bars (outside+inside pressure) to collapse the hose.

The problem went away when everything cooled down.

The radiator and the pressure cap is brand new-ish.

Is that a common problem on ST205?

How one would deal with P/S fluid spilling? It was at full when I started but not overfilled, the cap was on properly (obviously it is breathing type).

[pc]

I've always had a little PS fluid overflow in racing, I always figured it was something to do with repeatedly turning the wheel too fast for the pump.

[strx7]

the P/S resivous in my corolla does slop a bit of fluid, because it doesn't seal properly, due to the lid design.

[Adoom]

How one would deal with P/S fluid spilling? It was at full when I started but not overfilled, the cap was on properly (obviously it is breathing type).

Could you modify the PS reservior so it's taller but still only put the normal amount of fluid in it. Then any extra fluid that the pump is having trouble with can't make it overflow, the level just goes up a bit????

[Jdawg]

Do you need to underdrive your pulley's?

[MAGN1T]

When the seals in the rack start leaking , the fluid goes into the boots. You then top up the res, drive the car, park it up and the fluid from the boots goes back to the res.
As for the other prob, waterpumps can only cavitate when the cooling system is full of bubbles. Any noise from it is probably rusty bearings, probably caused by the seal thats failed due to too much pressure in the cooling system that's been topped up with water instead of antifreeze because the headgasket has failed.
No, nothing to worry about. Just keep driving it.

Steve

[Dell'Orto]

You dont fail to deliver do you Steve

[sergei]

When the seals in the rack start leaking , the fluid goes into the boots. You then top up the res, drive the car, park it up and the fluid from the boots goes back to the res.
As for the other prob, waterpumps can only cavitate when the cooling system is full of bubbles. Any noise from it is probably rusty bearings, probably caused by the seal thats failed due to too much pressure in the cooling system that's been topped up with water instead of antifreeze because the headgasket has failed.
No, nothing to worry about. Just keep driving it.

Steve

Bhahaha,

You know what? I look after my cars, and unlike most people I keep them around for really long time.

Ok, the steering rack does not leak, boots dry. Never had the spill problem on normal road, only on race track.
Car had Toyota long life coolant since day one.
Coolant is replaced once in 12 months.
Head gasket is not blown .
Again I know what bearings sound like. I also know what a cavitating pump sounds like, that was definitely cavitating.

How would you explain collapsing radiator outlet hose while the radiator inlet hose was under full pressure?

I agree this could be due to bubbles, but for bubbles to form there is no need for BHG, just red hot turbo that happens to be water cooled.

[allencr]

Fluid is foaming, increasing its volume. Also, heat expands & adds to the volume a little bit.
I doubt that you've heard cavitation.
The hose can only collapse from vacuum/suction. Your pump is trying to pull coolant from a clogged radiator.

[Mr Revhead]

I would hope it's not pulling from the outlet side of the pump

[iOnic]

the headgasket has failed.

Steve

If I had $1 for every time I've seen you say this...

[MAGN1T]

the headgasket has failed.

Steve

If I had $1 for every time I've seen you say this...

Pick a part has them all nicely lined up in rows.

Trouble is kids who don't know how to diagnose a pretty simple and common problem.

Steve

[~SlideWays~]

the headgasket has failed.

Steve

If I had $1 for every time I've seen you say this...

Pick a part has them all nicely lined up in rows.

Trouble is kids who don't know how to diagnose a pretty simple and common problem.

Steve

Man it must take you ages to remove all of those heads to be able to say that! And then put them all back on so it appears the headgaskets haven't been looked at.

[sergei]

The hose can only collapse from vacuum/suction. Your pump is trying to pull coolant from a clogged radiator.

Brand new radiator
Coolant is clean and very fresh.

[fivebob]

Brand new radiator .

Toyota or aftermarket?

If aftermarket which brand?

[sergei]

Brand new radiator .

Toyota or aftermarket?

If aftermarket which brand?

It is aftermarket OEM replacement (plastic tanks), bought locally, core and tanks looks exactly like original (even inside, looking through filler). The only catch that it is for an auto (got cooling pipe inside for trans cooler, which is not hooked up), original had top tank split at the time, so I needed replacement ASAP.

As for which inlet and which is outlet, Water pump (radiator outlet) inlet is on thermostat side I believe, this where I seen the hose collapsing.

[strx7]

Ok, the steering rack does not leak, boots dry. Never had the spill problem on normal road, only on race track.

its spillage out the non sealing cap from the G Forces

[fivebob]

It is aftermarket OEM replacement (plastic tanks), bought locally, core and tanks looks exactly like original (even inside, looking through filler). The only catch that it is for an auto (got cooling pipe inside for trans cooler, which is not hooked up), original had top tank split at the time, so I needed replacement ASAP.

At a guess I'd say that it's more than likely that if you measured the pressure drop across the core it would be higher than the genuine Toyota radiator. Whether that's due to a difference in design or material used, or if the auto trans cooler just adds a bit too much restriction would be hard to say.

[sergei]

It is aftermarket OEM replacement (plastic tanks), bought locally, core and tanks looks exactly like original (even inside, looking through filler). The only catch that it is for an auto (got cooling pipe inside for trans cooler, which is not hooked up), original had top tank split at the time, so I needed replacement ASAP.

At a guess I'd say that it's more than likely that if you measured the pressure drop across the core it would be higher than the genuine Toyota radiator. Whether that's due to a difference in design or material used, or if the auto trans cooler just adds a bit too much restriction would be hard to say.

It is possible...
So to prevent this without changing radiator I will need to insert a spring into the hose...

[cedwards]

where is the radiator fluid going to allow pipe to collapse?
surely if my basic understanding of hydrodynamics is correct a properly bled coolant system would not have the necessary space to displace enough fluid to collapse the pipe....
Unless: 1) it is pissing out the radiator into the overflow bottle,
or 2) there is an air pocket in the radiator/coolant system allowing compression?