water loss

[volvomadwoman]

hi, had the waterpump replaced as water was gushing out of the rubber seal as fast as i put it in, i know the valve inside in the drivers well leaks which will also get replaced asap but a round trip of about 5 miles empties the header tank with no visible signs of a leak anywhere apart from the wet floor on the drivers side? which i dont think is where all the water escapes to!
any thoughts
its a 940 2.3 turbo estate 94 auto

[Laird Scooby]

Get yourself one of those LED torches/headtorches that you have full brightness or a dimmer setting on. Find somewhere really dark without sky-glare, street lamps or similar to park at night, get your torch/headtorch on the DIM setting, open the bonnet and start the engine. You should be able to have a look round with the torch and see any water escaping.

The reason this works is because the water, if it's coming out in a jet somewhere will be a high speed series of water droplets. Using the LED torch on full brightness won't show it up as it's steady light so while you may (if you're lucky) catch the stream of water droplets, the surrounding area will also be as bright so will be difficult to see.

On the DIM setting, the LED is pulsed at high frequency, rather like a strobe light. It's not visible to the naked eye but point it at a jet of water and it appears to "freeze" the water drops mid-air, much like a timing strobe light works.

I found the cause of a mystery misfire and water loss using this method on my last 740 - pinhole in the top hose that was spraying backwards all over the distributor cap and plug leads!

Worth a try as it's relatively cheap/free to try and might save you a lot of head scratching!

[aardvarkash10]

If Dave's suggestion doesn't work, get the system presurre-tested and gas test the coolant for combustion byproducts.

FYI, I had a series of biblical component failures in the coolant system on a similar age 230FT. The heater valve begat the bypass tube begat the waterpump begat the radiator begat the head gasket...

Its the nature of a mechanical device that related components will fail at around the same time.

[Laird Scooby]

Originally Posted by aardvarkash10

FYI, I had a series of biblical component failures in the coolant system on a similar age 230FT. The heater valve begat the bypass tube begat the waterpump begat the radiator begat the head gasket...

Its the nature of a mechanical device that related components will fail at around the same time.

I remember your troubles with the water pump, radiator, turbo cooling hoses and so on - wasn't good.

The way you've written it though Ash i was kind of expecting a punchline about ".....begat the Great Flood" or something.

I call it "The Domino Effect" - one component falls down and a load then fall down after it in sequence.
These days if something relatively minor goes, i tend to do a "pre-emptive strike" on all related bits, make sure they're ok and renew any that look slightly suspect.

Might cost a little more at first than just fixing the basic fault but it saves a lot more money in the long run.

[Ian21401]

Originally Posted by Laird Scooby

Get yourself one of those LED torches/headtorches that you have full brightness or a dimmer setting on. Find somewhere really dark without sky-glare, street lamps or similar to park at night, get your torch/headtorch on the DIM setting, open the bonnet and start the engine. You should be able to have a look round with the torch and see any water escaping.

The reason this works is because the water, if it's coming out in a jet somewhere will be a high speed series of water droplets. Using the LED torch on full brightness won't show it up as it's steady light so while you may (if you're lucky) catch the stream of water droplets, the surrounding area will also be as bright so will be difficult to see.

On the DIM setting, the LED is pulsed at high frequency, rather like a strobe light. It's not visible to the naked eye but point it at a jet of water and it appears to "freeze" the water drops mid-air, much like a timing strobe light works.

I found the cause of a mystery misfire and water loss using this method on my last 740 - pinhole in the top hose that was spraying backwards all over the distributor cap and plug leads!

Worth a try as it's relatively cheap/free to try and might save you a lot of head scratching!

Well I never. That’s a crafty dodge, must try to remember it. Might give it a try in the garden one night just for fun.
Just a thought, the LED head torch I commonly use has three brightness settings using only 4 LEDs then 8 then all 12. Does your method still apply or does the torch have to have some other method of dimming the LEDs?

[Laird Scooby]

Originally Posted by Ian21401

Well I never. That’s a crafty dodge, must try to remember it. Might give it a try in the garden one night just for fun.
Just a thought, the LED head torch I commonly use has three brightness settings using only 4 LEDs then 8 then all 12. Does your method still apply or does the torch have to have some other method of dimming the LEDs?

Needs to be a single bulb that dims by PWM - Pulse Width Modulation - to alter the frequency of when the LED is lit to make it dimmer. On full brightness the LED is constant, on the dim setting, the fact it pulses the LED to dim it is what it makes it pick up the drops of water in the stream.

[Volvoluke]

Hi are you sure the waterpump is now water tight? 5miles out of the header tank is obviously very bad. My 940 was leaking this badly once and it was leaving a good sized puddle when parked up. My problem was the pump, and it was a flood after each drive. Look for coolant in the oil pan at the front and also further back the pipes by the oil filter can go very bad. Hope this helps

[Laird Scooby]

Originally Posted by Volvoluke

Hi are you sure the waterpump is now water tight? 5miles out of the header tank is obviously very bad. My 940 was leaking this badly once and it was leaving a good sized puddle when parked up. My problem was the pump, and it was a flood after each drive. Look for coolant in the oil pan at the front and also further back the pipes by the oil filter can go very bad. Hope this helps

That was the question i didn't want to ask but was in the back of my mind, hence the LED torch suggestion. That way the OP can see it for themselves if that is the problem.

As that was the original problem leading to the water pump replacement the common sense thought would say that's not what it is, however experience has shown recently that a lot of the new pumps leak badly, even when fitted correctly.

It's possible they fitted it wrong or didn't clean old limescale off properly causing the problem though.

[lynns hubby]

Not wishing to teach anyone to suck eggs here but its also worth noting that when fitting the new pump it needs to be "Snugged" up to the large rubber seal at the Head. That's why the bolt holes in the pump are elongated.

[Ian21401]

Originally Posted by lynns hubby

Not wishing to teach anyone to suck eggs here but its also worth noting that when fitting the new pump it needs to be "Snugged" up to the large rubber seal at the Head. That's why the bolt holes in the pump are elongated.

I had great difficulty with that top seal when I replaced my water pump some time ago. The “O” ring on the end of the rigid pipe into the back of the pump also needs to be carefully snuggled up into the pump. Is the pump to block seal leaking? It’s difficult to see it when everything is back in place.