My thirsty aw11

[jonno*]

hey guys,

since I've got my aw11 ('89 nz new) mr2 I've found the level on the header tank (when cold) will go down about a centimeter or so after each use. When it was nearly empty and the engine hadn't been run for a few hours i filled it all the way up, I've done about ~120k since then and the level on the header tank went down to around 2/3 full, so it definitely uses a little bit of coolant which seems a bit worrying.
the 4age has just clicked over 288,000ks and it has red cam covering lettering with t-vis.

did a compression test after letting the car sit cold for a few hours, results here:

cylinders

1 - 195psi
2 - 193~
3 - 205
4 - 205

the oil filler cap has no brown or murky shit inside it and i opened up the radiator cap and let it idle for a bit, no bubbles (well shit they would've been pretty obvious i guess haha) so i doubt the headgaskets gone.

there is a shitload of water pipes in the aw though..i don't see in the front or round the engine that are obviously leaking, so i'm kinda stuck here trying to figure out why it's using water :s don't think you're meant to need to fill up the tank each time you get etrol, so it can't be normal, right

any help would be appreciated,

thanks,

jono

[Mr Revhead]

so you fill it up and it always drops to the same point and no further?
could be thats where it sits after pressurising....
try a new GENUINE rad cap and see how that goes

try topping it up, and keeping an eye on it, if it keeps dropping you have a leak or something
if it doesnt, stop worrying

[jonno*]

Nah, it'd empty itself completely if I let it. looking closely the plastic on my radiator cap is actually pretty cracked and munted, i initially only saw one small rack and thought it was sweet. I'll get a new one from toyota tomorrow, and if that fixes it i'll be pretty happy I didn't take them up on their $100 an hour offer of looking at it when i rung them up last week

[jonno*]

Aight, bit of an update. Took it out to maretai before going to the bdo, found the coolant level still going down despite the new radiator cap

Think I may have found the problem though!

This pipe comes off what i think is the 'thermostat relief valve'



Now, the problem with it is...well....



what i think is that this pipe is meant to hook onto a little hole coming off the header tank, and recirculate coolant when the level rises, but the pipe has obviously fallen off it's mounting and been melted by the intake manifold or exhaust, because it was hanging under the car. if this is true then my coolant will probably be pissing outof the little hole on the header tank when it gets hot and the level rises, looking carefully i can see where water has dripped/splashed out from underneath the tank and left a wet looking mark.

going to try have a look at another aw and see if i'm right about what this ltitle pipe is meant to do, do you reckon this would be the right way to go? if not i can bite the bullet and take it to a garage who i think can pressurizes the cooling system and check for leaks?

thanks,

jono!

[cedwards]

I'm no expert on the aw11 cooloing system, but isn't that just one of the many bleed points in the system? you should only get movement through that pipe if the white tap in top photo is open??
How much coolant do you have in system? Normally if its at an appropriate concentration you will see green residue collecting around area's of leak.

[jonno*]

Ah yeah, checked the manuals, they label it as a "Coolant inlet housing air bleeder plug,' my guess probably wasn't very educated There's a bunch of photo's I've found showing the pipes connecting it to the tank though.

The level itself is sweet, there's plenty in there and i'll properly be able to identify the leakage when i clean the grime from the engine bay where i think the stuffs coming out.

[KwS]

god i hated trying to find faults in all the dub11s i have worked on... its worse than working on a subaru!

Can you park your car on a nice clean floor, so that if it drips youll be able to see the drops on the ground?

[jonno*]

Only leaks/loses water when driving bro, though i do have a nice little oil leak that makes its presence known on the somewhat clean floor

[Trls250s]

Could be the front of your waterpump housing, cause of the nature of the leak when the car gets hot the water evapourates off the engine block before you see its there when you look through your car after a drive.

Best thing you can do is get it up to engien temperature and have a look around under the engine and along the front of the block. If you can put it on jack stands when you do this, but make sure its jack stands, not a dirty jack cause the engine is going to be running when your going to have a look under the car.

Take off all the plastic paneling under the car too if you have any. It will be a pressure leak too (so the engine needs to be up to pressure as well). Look around the top of your gearbox, inlet, exit points on your firewall for your heater, sensor block on the back of the head and the inlet for the waterpump.

these are the only places i can think of that a pressure leak would come from. There arnt a hell of a lot of waterlines that come off the 4age.

If its done 288,000 it could proberly use some love, so suspect gaskets and fittings haha.

[Caveman]

hey ive taken my aw11 apart head to toe and all I can say is the standard water lines were fcuked! The standard hoses were fine apart from being slightly bittle however the flares where the hose attaches to steel pipe was rusted completely.

To get to the water lines under the car you need to remove the fuel tank, no easy way about it first check all the barbs where the hose attaches to the steel pipes. Under the car and in the frunk where the hose attaches to the heater core. If they are fcuked you know what needs to be replaced. Pull the fuel tank then pull the pipes and replace them.

Second check the water pump for leaks as this is common on all old cars.

Failing that your in the deep, sorry mate

hope you get it sorted

[jonno*]

fortunately replacing that melted pipe has fixed the problem, hasn't used anything since i cable tied a new bit of hose onto there! would've been a pretty major issue if that hadn't fixed it

cheers though caveman & trls250s, good advice and i'm stoked i don't have to use it!