I've just discovered the rad system isn't holding water/pressure too well!

 

I went to fill the system up and it was like a bottomless pit, I tried filling the expansion tank neck on the R/H side of the bay which did seem to drop water.

 

Filling the rad seems to go on forever and there seems to be no-where dripping when filled from this point???

 

I'm guessing the right hand tank can't be pressurised, so therefore that leak is a separate issue?

 

GAHHHH!!!

are you supposed to put water in the expansion tank side ?????? as i thought you fill the rad and it circulates into the expansion tank?? i may (probably am) be wrong?

Water only goes in the rad, and no it's not pressurised so it's only an overflow tank , but you need to fill from the rad eng off/ ign on, with the bleed screw off

Here you go >>

 

1. Make sure the car is parked in such a way that the front is higher than the back of the car. This will force any air bubbles to come to the front & top of the radiator and escape through the bleed screw hole.

2. Remove the bleed screw and radiator cap - ignition off. Top up coolant through the radiator cap hole until you can see water.

3. Make sure you've got approximately 600ml of coolant in the expansion tank.

4. With the bleed screw and rad cap OFF turn the engine on and set the heating system to maximum temp (40C & A/C off). You can put the fan on max as well but this is less important.

5. Over the next 5 or so minutes the coolant level will drop and you'll also see air bubbles appear. Once the coolant starts to overflow from the rad cap hole you are safe to put the bleed screw and rad cap back on.

6. Job done! Check level again every other day for the next few days to make sure the level isn't dropping

 

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Edited August 29, 200916 yr by ck300z

Thanks for the replies.

 

This is quite strange now, I just refilled, let the air escape and kept topping up until the rad was full and seemed to hold the level, I started the car with the cap off and found it went down some more (no real surprise there) I noticed the are very small bubbles which are creating a very small amount of froth (there is no mixing of oil and/or water) and the pressure doesn't seem too high in the pipes - there's still no dripping underneath although there originally was what seemed a wet patch on the L/H side of the rad (2 or 3 drips).

 

I did notice that the upper radiator hose seemed to have some hissing from it when I turned the engine off, now I've pinched the jubilee clip up and it no longer does it.

 

My possible thoughts are 1) a very small head gasket leak between a cylinder and the waterways - enough to create a very small amount of froth and possibly draw water back into the bore as cooling down takes place. 2) The rad has a tiny leak which once the engine is warm enough is sufficient to dry the water as it goes.

 

Please shoot me down in flames with these theories as I'd like a simple repair lol!

I did notice that the upper radiator hose seemed to have some hissing from it when I turned the engine off, now I've pinched the jubilee clip up and it no longer does it.

 

Watch that you have not just tightened up over a crack in the hose. If it was hissing there it would also have been losing water from there before. It could be your leak. You better hope not a head gasket!!

 

Check that the system pressurises when the engine is hot. Firm hose. Good seal on the rad cap. Watch out for ejection through the overflow tank - this would point to gas entering the water jacket and expelling the coolant via the rad cap - bad sign..

I did notice that the upper radiator hose seemed to have some hissing from it when I turned the engine off, now I've pinched the jubilee clip up and it no longer does it.

 

Watch that you have not just tightened up over a crack in the hose. If it was hissing there it would also have been losing water from there before. It could be your leak. You better hope not a head gasket!!

Surely if there was a crack in the hose, tightening it wouldn't have helped?

 

Check that the system pressurises when the engine is hot. Firm hose. Good seal on the rad cap. Watch out for ejection through the overflow tank - this would point to gas entering the water jacket and expelling the coolant via the rad cap - bad sign..

The system does pressurise, but not sure if it's enough - I would have thought the pressure would have been higher if there is a HG leak as the cylinder would be forcing air in?

 

Do you have any good news lol!

Has it had a new rad cap lately?

Has it had a new rad cap lately?

 

No but I think it's about time, although the rad cap is only there to let out excess pressure should it need to...there hasn't been any water released from the cap, so I guess it's probably ok.

 

I did notice that the upper radiator hose seemed to have some hissing from it when I turned the engine off, now I've pinched the jubilee clip up and it no longer does it.

 

 

Just a quick thought, re this, mine was losing water but couldnt locate for ages. Turned out the top rad hose had gone soft, think its called vulcanised. when at full temp it was letting a mist of water out, but due to the engine heat it evaporated instantly.

After a decent drive check the condition of the top hose, it should be under pressure but not expanding to much. mine was the size of a tennis ball.

Got a new OEM hose and problem sorted.

Thanks Stu, the hoses all seem to be in good order. I'm off to zedworld next week so if it's not sorted perhaps they can take a look.

Seems to be settling at a higher pressure - I added K-seal which is excellent stuff.

Seems to be settling at a higher pressure - I added K-seal which is excellent stuff.

 

Not familiar with K-seal but hope its not like radweld, The amount of overheated Z engines I've pulled apart with this sort of stuff clogged up in all the narrow waterways.