Still got bizarre overheating problem PLEASE HELP

[Dan318-is]

afternoon men

i had an MOT on wednesday (passed) but the people who did it left the car running for about half an hour. driving it home i saw the temperature gauge begin to shoot up, so i opened the bonnet and could smell coolant. i let it cool down checked the water and sure as hell it was leaking. luckily i had some water topped up in my boot so it got me home.

Anyhow, drove 3 hours yesterday to londonish and back, and the car didnt flinch. The heating was on the whole time, the gauge stayed at quarter, but the car did not over heat

so why does my car not overheat or leak when the heating is on, but leak and overheat when it is not.

i no the heating sucks air from the engine bay but why would it only heat up to a certain temp?

Please help!

[tylerma]

where is it leaking from mate

[jonbuoy]

afternoon men

i had an MOT on wednesday (passed) but the people who did it left the car running for about half an hour. driving it home i saw the temperature gauge begin to shoot up, so i opened the bonnet and could smell coolant. i let it cool down checked the water and sure as hell it was leaking. luckily i had some water topped up in my boot so it got me home.

Anyhow, drove 3 hours yesterday to londonish and back, and the car didnt flinch. The heating was on the whole time, the gauge stayed at quarter, but the car did not over heat

so why does my car not overheat or leak when the heating is on, but leak and overheat when it is not.

i no the heating sucks air from the engine bay but why would it only heat up to a certain temp?

Please help!

It does'nt suck hot air from the engine bay mate otherwise you'd be breathing fumes all the time

The Matrix has water running through it from the engine thus' the fan blow's the hot air through from the pipe's or something like that.

You may have a blockage or your viscous fan is'nt working properly.
When your temperature gauge starts to rise try reving the engine to get the fan spinning faster or get a stick in the fan (whilst holding it), the engine will get upto temperature and the fan should try pushing the stick out of the way, if not then that's your problem.

Good luck

[tylerma]

could also be an airlock
have you tried bleeding it

[Dan318-is]

sorry about heating thingy i new what i meant

the fan works properly, if u spin it when the engines off it stops like it should, and it always comes on

the leak is coming from under the inlet manifold somewhere, iv removed heater jacket and replace loads of hoses, i dont understand why it only does it when its hot tho?

an how owuld an airlock cause a leak? ne ideas how to get rid of them - cos i havent bleeded system yet no

i need to do some research

[jonbuoy]

Bleeding the system

From empty

Take bleed screw out
Pour water into water tank until the water comes out of the bleed screw hole.
Start the engine and let water settle.
Once settled the water level may not be at the right height so rev the engine so the water shoots out or top up, what ever is nessecary.
Once at desired level, put the bleed screw back in and cap back on.

Job done!

[tylerma]

i would say start off by bleeding it
you may have a bleed screw on top of the radiator

[Dan318-is]

im guna try it now

u lads r legends

[jonbuoy]

Did you get my pm and how's the car coming along?

[Dan318-is]

no PM dude

[tylerma]

Did you get my pm and how's the car coming along?

if you meant me mate
pm recieved but i cant send it as it wont open when i recieve it

as for the car nothing sorted yet
but within the next 2 weeks hopefully

[Dan318-is]

doh!

[jonbuoy]

Sorry 318-is, did'nt mean to confuse you. Have you read the "How to" guide i put up for bleeding? Does'nt take long to do the job either mate

Tylerma

Had the same problem, the page did'nt come up for me either. There is another post on there with a link of a "How to" guide. Try that, it's pretty simple.

[Dan318-is]

lol no worries

im guna do it once iv eaten my cheese on toast

mite also change the thermostat today cant do n e harm rite?

[jonbuoy]

Won't do any harm but there has alway's been a saying, "What don't need fixing, don't fix it."

[Dan318-is]

too true dude

i think il bleed it n go for a long drive c what happens

let yal know later

[jonbuoy]

Good luck geese

[tylerma]

good luck Dan

[Dan318-is]

ok bled it easily enough and no air seemed to come out

was warm engine too

[jonbuoy]

What did you actually do when you bled it?

[Dan318-is]

topped up water about 3 inches above level, heater setting on full,. position one, run engine, let it warm up, undid bleed screw until no air was coming out

[JOSEMI]

Problem: you're losing water and air is getting in the cooling system, check for water leaks inside the cabin, as yur matrix's pipes may have blown with the heat escaped in the garage. Beware, you may lose your head gasket now too !
Fix: change internal water pipes from the heater matrix, words for those who know...

[Dan318-is]

how hard is this job?

r the pipes much from the dealer?

[jonbuoy]

how hard is this job?

r the pipes much from the dealer?

If your not mechanically minded, this would be a job for someone else to do geese. You might get a little fustrated with it and end up selling like everyone else.

[Dan318-is]

never!!

how much would it cost?

[Geeman]

I had a similar problem with my 318iS when I first got it... would overheat unless you drove with the heater on.

Ended up replacing everything... radiator, water pump, thermostat, all water pipes, etc.

[Dan318-is]

theres no water in the footwells or behind the console, not that i can feel n e way, but that is when its cold so obviously there wont be

but theres no stains etc

im guna replace the heater matrix pipes first then see what happens

i still dont understand why it only leaks when hot tho

[tylerma]

would i be right in saying
it only comes out when hot because that is when the water system is under pressure

[Dan318-is]

thats precisly what i thought but i dunno mate

if these heater matrix pipes dont to it i mite just buy a cooling system lol

its deffo not the pump, have also had new water pump belt, iv had compression test, fan works fine, radioter has no cold spots, theres no major leaks, thermostat operates fine i presume theres certainly no leaks around it, have removed heater jacket,

[tylerma]

and it leaks in the general area of the throttle body yeah

[Dan318-is]

below it is where it use to leak, but since iv removed plate it hasnt done so

when it got hot before i could hear the leaking coolant hitting the gearbox housing and sizzling and could smell it

now i can smell it but cant see it

[tylerma]

below it is where it use to leak, but since iv removed plate it hasnt done so

when it got hot before i could hear the leaking coolant hitting the gearbox housing and sizzling and could smell it

now i can smell it but cant see it

this sounds almost identical to a problem i had
when you leave the car is there a puddle of water
after a run

[Dan318-is]

im not sure, the problem is there i always drive with heating on to make sure now u c?

so when i have run it neevr does leak, but the coolant level always drops a little if i check it after

[tylerma]

i would say get your rad pressure tested
but i dont think you can because of the plastic tank built on the side

it may be a slight split in your rad mate
thats what the problem was with mine

[Dan318-is]

how would that be linked with the heating system tho?