What Happens When The Water Pump...

[Andyn]

dies?

I'm curious what chain reaction of events will unfold once the water pump dies, and what will be noticable when driving. Eventually it will end with the car overheating...

Edited April 28, 2006 by Andyn

[Trust33]

basicly...

[chrissso]

Well, the way you put it, the end is the begining.

The pump fails,the water stop circulating, and the car overheats!

Some other things that might happen will be...

It might sound funny - i.e. not normal.

Steam may vent from the under the bonnet.

Your temp gauge will be in the red zone..

Then it might seize as the oil turns to carbon..??.

Lotys of other nasty stuf, etc, etc.

My question...why do you ask?

[Andyn]

Chrissso: It's relating to my thread from the other day (http://www.skylinesaustralia.com/forums/index.php?showtopic=114933&hl=)

I didn't get enough feedback on the cause of the car idling higher/revving higher, before the radiator crack incident, so I'm doing further research on all the possible causes.

So I was thinking whether the water pump could have died, which caused the revs to be higher than normal, and since there is no circulation and the water/coolant, the liquid is not being cooled which made it rea hot and hence my radiator top tank burst.

I just want to confirm with someone, whether a dead water pump may cause revs to be higher, or is this unlikely? Otherwise let us know possibly reasons how revs could be affected. I know air conditioning is another one.

I want to get to the bottom of this issue, so when i replace the radiator it won't happen again.

Edited April 28, 2006 by Andyn

[chrissso]

I'm my experience, higher revs at idle can be a result of over heating, but then it gets to a point where the revs will drop and the engine stalls because it's too hot. When it gets too hot, the coolant starts to boil in the cooling system and the pressure rises. The pressure will keep on building up until it overcomes the weakest point in the cooling system, and blows out of this spot. When this happen, most of the coolant is forced out, and then this only compounds the overheating effect, as there is now not much coolant left. Then, it gets worse from there. Oil boils, and pinging and detonation happen.

I just read your other post, and mate, you should have stopped when you saw green liquid on the floor. Leaking coolant means that something is wrong and it only takes 15 minutes to f**k an engine with a bad cooling system.

If you see some of the symptoms above, check your temp gauge. If it's high, then something is wrong. It's not always going to tell you if the engine is too hot, but it's a start.

Chriso

[Jolinator]

unlikley waterpump will effect rpms, normally radiators tend to go at the plastic top tank because its the weakest point that sees the most heat, decent radiators wont have plastic endtanks.

[Craved]

water pumps also leak out of the hole in the bottom of them when the seals start to fail.

[Andyn]

I'm my experience, higher revs at idle can be a result of over heating, but then it gets to a point where the revs will drop and the engine stalls because it's too hot. When it gets too hot, the coolant starts to boil in the cooling system and the pressure rises. The pressure will keep on building up until it overcomes the weakest point in the cooling system, and blows out of this spot. When this happen, most of the coolant is forced out, and then this only compounds the overheating effect, as there is now not much coolant left. Then, it gets worse from there. Oil boils, and pinging and detonation happen.

Mate this is spot on and sounds exactly what happened to me. Now Im trying to figure out why/how it was overheating in the first place, before the radiator cracked...

It was working the day before fine. Just when i started it up that morning it was idling higher/revving higher.

Aircon/Fuel pump? Any input is appreciated guys.

[Master]

People that more the ECU set up well might be able to answer this one, its not uncommon for a temp compensation. ie. If the ECU sees rising temps, it will add more fuel in an attempt to reduce combustion temps. Also your oil is at a lower viscosity = less frictional resistance thats gotto add a few revs. Sometimes when things like this happen, it can be two totally separate things goin on. The most common cause of over heating IF everything else is all honky dory with ur water pump/ coolant/ fan/etc etc is the thermostat valve. Prone to get jammed with corrosion and hence just keeps recirculating water in the head circuit and not into the radiator. Easiest way to check this is to have the car upto operating temp and squeeze the top hose goin into the radiator, it should have pressure.

On another note, not many people know this, but if ur on a border line with temp and ur unsure about it, wind down ur glass and turn on the heater. It acts like a radiator too.

[wrxhoon]

water pumps also leak out of the hole in the bottom of them when the seals start to fail.

Thats what usauly happens to water pumps, they leak first from the telltale .

[chrissso]

Mate this is spot on and sounds exactly what happened to me. Now Im trying to figure out why/how it was overheating in the first place, before the radiator cracked...

It was working the day before fine. Just when i started it up that morning it was idling higher/revving higher.

Aircon/Fuel pump? Any input is appreciated guys.

Well its a bit of a "how long is a peice of string" question.

There are so many things that can cause overheating from really simple to really big issues.

Examples I have seen.

rotten radiator core

leaky coolant system

blocked coolant system

not enough coolant in the system

wrong coolant used

bad thermostat

blown head gasket...

These issues will have other symptoms as well to help diagnose the issue. But the main big noticable symptom is overheating.

Your gunna have to see a mechanic

I had a company car that was overheating, the mechnaic couldn'tfind anything visibly wrong, and blamed it on the head geasket.

It was changed and a week after, the car was over heating again.

Turned out to be the thermostat wouldn't open and was getting stuck every now and then.

Obviously, the boss doesn't use that mechanic anymore...

[Andyn]

Hey guys,

Just got radiator all fixed and was flushing out the old coolant out of the pipes around the engine with a hose, and what should of happened is i feed water from top hose and it should come out bottom hose.

But water came out from a hole under the engine. Doesn't look right to me. Is that the relieve hole you guys are on about?

Can anyone shed some light on this? I have a sneaky suspicion what could have caused all this... but keen to hear ur opinions.

Edited April 29, 2006 by Andyn

[Hootchy]

water pumps definately f**ked

have fun changing it as it's a bastard

Edited April 29, 2006 by Hootchy

[Andyn]

water pumps definately f**ked

have fun changing it as it's a bastard

Thanks for the words of encouragement

Can u elaborate on "have fun changing it as it's a bastard"...?

[wrxhoon]

You need a new water pump and while you are at it a new harmonic balancer too.

[Sydneykid]

Water pump dies? They don't all die using the same method.

1. Some wear out their bearings and scream. Until the aluminium casing fails and bits go everwhere, jam up the cam belt, break it and valves hit pistons. Very ugly.

2. Some corrode the impeller and slowly stop pumping water around. Never seen that on an RB. Mostly because the owners are smart enough to run coolant, not plain tap water.

3. Some corrode the aluinium case and leak water (see #4). Never seen that on an RB. Mostly because the owners are smart enough to run coolant, not plain tap water.

4. Some wear out the front seal and leak a little water. It is pretty obvious, when you park the car, there is a puddle of coolant. This is not so bad, as long as you keep topping up the radiator water. They will go for some time before the leak gets really bad and you have to fill up the radiator several times a day.

It sounds to me like you had #4 and didn't notice the leaking coolant. So you didn't fill up the radiator. Eventually the radiator level gets so low that there isn't enough coolant left to cool the engine and it boils.

Have a look at the tutorial on changing the cam belt, that's basically what you have to do to change the water pump.

cheers

PS; I look at the surface under where I park my cars everyday. Leaks are early signs and catching them before they get serious is a good idea. At the very least, it tells you what you have to fill up until you get around to fixing up the leak.

[Andyn]

Thanks everybody for your replies so far. Has been good to confirm and introduce other things that I was thinking.

Well it sounds like the water pump was the culprit all along and I am convinced that the Front seal is gone and this needs changing.

I didn't notice the coolant leaking, and there wasn't many stains residues where it is normally parked, so I'm guessing it wasn't leaking for that long.

Apologies if this is clear to others or has been touched on in the post, but its still not clear to me. This is what I think has happened, after doing some research and reading ppls replies, please correct me if you disagree with "ANYTHING".

Let's assume that the front seal of waterpump was worn out and it's coolant has been leaking from the water pump hole (This hole)

Then the coolant level dropped to a very low level. Then this caused the engine to overheat - which makes the revs higher and idle higher (Question 1: I'm not sure how exactly it impacts on revs - if someone can explain this it would be great). As the engine was overheating it was boiling the coolant and so the steam caused the weakest part of the cooling system to crack - which was the radiator top tank.

Now in theory this sounds all good and logical, but there are still somethings that don't match up with this story.

I looked around the area where it's normally parked and there is no real evidence of a huge leakage (there was some coolant around but that could of been when i was flushing the radiator out, before I took it out). So if it was leaking it hasn't been for a long time. To add to this, the first instance when the radiator top tank cracked I checked the coolant reservoir but it was still a between 1/3- 1/4 of the tank full. (Question 2:) Shouldn't it have been around the min mark (or empty) if there is not much coolant in the cooling system?

When I flushed out the coolant from the radiator the day after the incident - I only got under 500mls of coolant (which was perfectly green). Maybe the coolant reseirvoir was telling me lies before the incident? I know after the top tank cracked (This Part of radiator) the coolant can't transfer from the cooling system to top tank but it should have been fine before the crack.

Also my temp sensor is sensing something (as it moves to the middle position when the car is warm), but when I was driving before the incident, and revs are higher (which we think was the cause of overheating) the temp sensor was still in the middle. (Question 3 My temp sens is reading something but could it have been faulty? I would have thought they would either work or not work)?

(Question 4: Can someone explain what they think could have caused the Overheating, keeping in mind the extra facts I mentioned in this post?)

(Question 5 Also to replace the Waterpump do I have to take all the things off to replace the timing belt? If so then I may as well do timing belt together, however if not then I will just change waterpump, due to budget constraints and not knowing the condition of the engine after this incident.

Edited April 30, 2006 by Andyn

[Sydneykid]

1. Water evapourates, you need to look everyday, not come back a week later. Coolant in the overflow tank is a sign of NOTHING, if you have an air leak. A worn seal in the water pump is an air leak, so instead of sucking coolant from the overflow tank it sucked air past the leaking seal. You need to check the water in the radiator.

The fast idle sounds like another, unrelated problem, fix the radiator and water pump and then worry about the fast idle. If it is still happening.

3. The water temp sensor only works when it has water (coolant) to sense the temperature of. If the water level gets below the temp sensor then the readings are unreliable. They don't like sensing air temperature.

4. You let the water get too low in the radiator, because you didn't check it

5. Yes. Don't worry about spending money on parts, you will need them for this engine or the next one anyway.

6. If you are worried about the condition of the engine, then get a leak down test and water system pressure test. That will tell you if anything is wrong. Mobile mechanics can do this if you are too scared to drive it to your local workshop.

You are over analising, if you had spent the time fixing it instead of writing 3,000 word posts it would be going now. Get on with it.

cheers

Edited May 1, 2006 by Sydneykid

[grigor]

You didn't thank SK for his lengthy replies, or advise if you had purged the air from the cooling system when you flushed and re-filled.

Purging the air is such a simple job but with big consequences if forgotten.

[Andyn]

Thanks for the explanations SK. Makes sense now.

My fault for assuming looking at the radiator reservoir is a good indication of how full the cooling system is. How would you check the water level in the radiator actually?

I will do all the necessary things this coming week. Haha - Overanalysing is in my nature, but better to know a bit of background knowledge, before you get to the mechs (who sometimes aren't as honest and as knowledgble, as ppl on this forum). Also it's long weekend and I can't get any parts till tommorow.

Anyway should be good to get it back on the road.

p.s Grigor: For the record, I did thank SK indirectly in the posts and directly in PM's we have had, so don't make any silly statements without knowing all the facts. No hard feelings though.

Also not sure about the air thing - My ex-mechanics did it. It's not very substantial anyway whether they did now. Just gotta make sure when they flush it this time its all done properly. You live and you learn. Thanks again for everyone who contributed.

Edited May 1, 2006 by Andyn