Water leak. please help me find it

[biglamb]

Hi, all.

This kind of follows on from my last post (header tank). I am loosing water from my 2001 hdi 110 exec. I have had a good root a round and a right old look see. I can find no drips, no wet pipes or no dodgey looking pipes the rad looks fine and as you all know its well protected from any flying debris. I have however noticed some water marks and indeed water around the header tank cap after a run today. I kow the cap is presurised. But should it hiss and leak after a normal run, bearing in mind that after the run, the tank was about 400mm too low of water. so its not just spitting out the excess water. Is this leak/ spitting enough to loose the 400-500mm on a 60 mile run. or is this excess pressure caused by a low tank due to a leak yet to be found?? I im trying to look ant the water pump, but im no mechanic. so this will sound silly to all in the know, but is the water pump the lowest item on the belt? I think it is, because it dont look like an alternator, but it is located right at the bottom of the engine near the sump. Just doesnt look right there? This lump does look like it has a cleanish area running down it, maybe from leaked water.
Just to be certain. it is not the head gasket that has gone causing a leak. There is no sign at all to indicate this. The water loss does not seem to be effecting the water temp yet, so it is cooling the engine ok. the guage does not even reach 90 degree, driving at 80-85 mph for about 15 miles. So can anyone help me? am i even making sense? Thanks in advance peeps, and enjoy your pugs.

[steve_earwig]

I'm afraid you won't be able to see the waterpump without removing the timing belt covers, I guess the lowest object on the belt is the crank pulley.

Is it really hissing water past the cap after a run?

[biglamb]

thanks for that. i guess i must be looking at somthing else down there.
Yes i really is hissing water. its not bad, more of a hiss and a spit. hard to describe. I was wondering if the cap might want replacing. i had a bmw once that kept over heating, and we tried everything and could not find a problem, eventually i change dthe cap for a brand new one and it never overheated again. simple as that. so when my local stealer is open away i go.

[teamster1975]

Thermostat may be iffy
What's the running temperature like?
Would be worth taking a look at the oil filler cap for any creamy coloured residue (I really hope there isn't!!)

[biglamb]

no creamy oil definatly not the head gasket, if thats what your thinking. and the running temp is anything between 80 and 90, 80 ish normal driving and 90 ish medium driving, (85 ish motorway) but always constant and predictable. But i dare say if i let the water level drop too far i might see a change.

[steve_earwig]

What's the running temperature like?

the guage does not even reach 90 degree, driving at 80-85 mph for about 15 miles.

I presume the cap has a spring in it so I'd think changing it might be an idea. At least it'd eliminate it as a possible cause. *crosses fingers*

[teamster1975]

I only found the leak on mine when I'd given the car a bloody good run and got the system up to pressure.
May be worth doing a flush and refill; it may not have enough (or any!) antifreeze in it
I'd definitely change the pressure cap too as Steve says.
If it carries on losing coolant try some K-Seal as recommended by James our resident mechanic!

[biglamb]

Thats the plan thanks. i think a new cap and a full flush and refill with fresh antifreeze. are these simple to do? Drain, then fill wile running the car and the breather opened.? Its been a long time since i had to flush a system.

[teamster1975]

Thats the plan thanks. i think a new cap and a full flush and refill with fresh antifreeze. are these simple to do? Drain, then fill wile running the car and the breather opened.? Its been a long time since i had to flush a system.

Piece of piss. There's a tap on the bottom of the rad where the bottom hose goes in. Take the pressure cap off, get a largeish container and crack open the tap!
When you refill there are various bleed valves to get the air out of the heater matrix etc; you'll also need to fashion a container to go over the filler neck to keep the water level above the bleed valves (or get the wheel up on a kerb like I did )
Once you've filled it run the engine for a few mins then top up the coolant. Take it for a drive and let it cool then check your levels again.

[biglamb]

exellent, you guys are great.
where are all the sed bleed taps.? i will by making one of those patented buxton bottle jobbies, ill use me old tank cap, and some good glue. top stuff ( royalties in the post mate thanks). How much antifreeze do you recomend.

[teamster1975]

I can't help you on the valves cos I've got the petrol turbo which is a different setup; there's one next to the right hand side of the rad (it's got a dust cap screwed onto it); I think Steve has the hdi so he'll probably know. To be honest I didn't bother with them. I just kept checking the levels each time I took the car out and kept a gallon of coolant in the boot & a funnel

[mjb]

Take the pressure cap off, get a largeish container and crack open the tap!

NO!!! Tap opens first, THEN the cap, else you have coolant gushing out all over you!

or get the wheel up on a kerb like I did

OI! That's my advice!

Once you've filled it run the engine for a few mins then top up the coolant.

I'll elaborate on this. When the coolant temperature reaches about 80-90c (dependent on the thermostat's opening temperature, which varies from model to model) the water level will suddenly drop by a fair old amount putting it well below minimum. You'll want to get water in there pronto.

Must must must bleed! Look for one on the approx 3/4" pipes coming through the bulkhead on the passenger side, and one near where the Haynes says your thermostat/coolant temperature sensor is

[teamster1975]

NO!!! Tap opens first, THEN the cap, else you have coolant gushing out all over you!

Really? It's not under that much pressure with the engine off
That's what I did in any case & I didn't get soaked

OI! That's my advice!

Na na nana na

[mjb]

NO!!! Tap opens first, THEN the cap, else you have coolant gushing out all over you!

Really? It's not under that much pressure with the engine off
That's what I did in any case & I didn't get soaked

I've got big arms so moving my arm out of the way wasn't exactly a quick procedure on the tubby ;)

[steve_earwig]

Umm, my HDi doesn't have a drain, I had to take the bottom hose off.






Any good? Why won't psp let me play with arrows??

The idea is to undo the drain, then take the cap off once the flow starts to ease up, or it really will come out at right angles. A bit like draining the oil really. It probably doesn't matter so much but it could go up your sleeve...