[Mk2] [NA] coolant leak!!!!

[glimited2000]

Just seemed to have got a coolant leak but it only happens when i put my foot down and when it leaks it leaks loads! When I top it up it isnt leaking out. Its defently not got too much water in it because when it leaks my car begins to over heat!! Anyone have any ideas?
Thanks
Rob

[Dale_V]

a leak could be anywhere, if it is actually leaking and not boiling the water then you need to find out where the leak is coming from

it could be as simple as a leaky rad, or as bad as a cracked block!

[glimited2000]

if it was a cracked block then would the water be leaking onto the floor?

[Dale_V]

if it was a cracked block then would the water be leaking onto the floor?

maybe, maybe not

I had a cracked block and it was from the water jacket to the outside of the block, and when driving steady it would be fine, as soon as the revs went up it would spray water out, but by the time I had pulled over to look for water there was none on the outside of the block it took me months to diagnose that one!

or another case could be that it has cracked internally on the cylinders and so its being burnt in the combustion process

a cracked block is the worst case scenario, it could be many other things. I would start by bleeding the system properly, as just topping it up will cause air pockets and as soon as you give it the beans the temp will rise.

bleed the system> run around in it > monitor the coolant level after every trip... bleeding the sys could solve it, if its still leaking then you need to find if its internal or external!

check the undertrays front to rear, poss leaky rad, coolant pipes, rubber hoses not sealing properly against oxidised alluminuim

that should keep you busy

[glimited2000]

the water is leaking from around where the over flow is, so its the left hand side corner but I cant see anything!!!!!

[Dale_V]

the water is leaking from around where the over flow is, so its the left hand side corner but I cant see anything!!!!!

Right to me that means its not actually leaking from there as the overflow tank is not pressurised to leak out, but it sounds like pressure is building within the engine coolant system and then its being pushed thtough the filler cap neck (metal cap) to the overflow tank, eventually overflowing through the pipe onto the floor.

[glimited2000]

probably sounds about right. Do you know what might be causing this to happen?

[Dale_V]

probably sounds about right. Do you know what might be causing this to happen?

pressure within the coolant system is ususally a blown headgasket or cracked block

like I say get the coolant bled properly, get rid of pretty much all the coolant thats in the overflow tank but leave a little in, so it measures around 6 inch from the bottom of the hose that goes into the tank.

If you do the above, then go for a drive, let the car cool down FULLY and now check the coolant, it should still show 6" on that pipe, if its more then it means coolant is being pushed through the system to make way for exhaust gasses, and is dumping the excess in the overflow

[Turbocarl]

Sounds similar to my problems a while ago matey - replace radiator cap before you do anything - ya might get lucky!!

[glimited2000]

right okay mate I'll give that a go first.
thanks

[going4the1]

+1 It'll be the radiator cap

[JohnnyC]

Sounds similar to my problems a while ago matey - replace radiator cap before you do anything - ya might get lucky!!

I'd go with that AND what Dale said about getting the system bled properly.

[glimited2000]

okay well i do the bleeding first then look at changing the rad cap. fingers crossed!

[blue2]

Hi Guys,

May be able to offer some advice, I have a similar problem and have spent weeks and a huge amount of money and time investigating it. I cant see the leak in mine, it just leaks about a litre every 1000 miles or so.

Anyway, first off I changed the radiator cap, no joy. Then I was told by the gargage that the radiator had a small crack in it and was sucking in air which was causing the temp to rise and leak coolant. Ok, so changed that and still it leaked coolant.

Went to another garage who pressure tested the system, no cracked block and head gaskets were fine, good news then. They did see that one of the coolant pipes in the engine bay was chucking out steam when hot.

So, as a last resort and due to time constraints I went to toyota and had them check over the system completely. In all I had the 4 coolant pipes (the ones from hell) replaced, the coolant changed and checked for leaks.
This cost me a fortune and I am still getting exactly the same problem. Its a bloody mystery but Im certain it has to be something simple that I and the gargages have overlooked.

So, before spending any money, check everything first or you may end up in my situation, skint and peed off!!
My car is now juddring and sounding like its only firing on a few cyliners, not sure if this has anything to do with it.

Number 1 check thoroughly for trapped air in the system.

[glimited2000]

just looked and the water is defently coming from the over flow pipe. Would a cracked head still be a possibility? No white build up under the oil cap or on the dip stick either.

[Dale_V]

i very much doubt it will be a cracked head, more like a blown headgasket or cracked block... Have you followed mine or other peoples reccomendations to at least test the system?

[tomTRR]

Have you looked to see if water is coming out the exhaust (in large quantities), after warming the engine?

I've had the head gasket go on me twice now. The second time water was really p***ing out the exhaust =[

[glimited2000]

just been searching through the internet about this bloody coolant leak and cam accross this http://www.yorksoft.co.uk/mr2/index.asp ... il&uid=339 I know he had a mk 1 but this is exactly the same problem that im having. Has the mk2 got this valve he is talking about and if so do you know anything about it?
thanks again

[Dale_V]

have you followed the steps I have mentioned several times?

[dai21t]

I found a coolant leak on mine by making an adaptor to go in the top hose by the filling cap with a presta valve on it. Just pressurised the system using a bike pump and the leak was easy to find.