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(Post Link) post #1 of 26 Old 27-07-09 Thread Starter
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Help v6 gt high pressure coolant

Hi

About a week ago noticed the coolant was leaking from the coolant tank cap, so brought a new one to try, was ok for a while but system seemed under very high pressure & if sat in traffic temp would creep above 90 i know the damage this can do so made sure that it went no higher by stopping until it cooled down & traffic cleared.

Went for a new thermostat today had that fitted hoping that the water was not getting through, made no difference & on the way home from work the lower hose on right hand side of engine (looking from front) has given out & lost all coolant from a split in that. Luckily was within spitting distance from home & coasted to driveway

The water is a rusty orange colour so hoping the radiator is blocked? But would this result in the high pressure?

Have had a sniff test done & indicates head gaskets are ok. Any help or advise would be greatly appreciated

Thank you
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(Post Link) post #2 of 26 Old 27-07-09 Thread Starter
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v6 gt v.high pressure coolant

Hi

About a week ago noticed the coolant was leaking from the coolant tank cap, so brought a new one to try, was ok for a while but system seemed under very high pressure & if sat in traffic temp would creep above 90 i know the damage this can do so made sure that it went no higher by stopping until it cooled down & traffic cleared.

Went for a new thermostat today had that fitted hoping that the water was not getting through, made no difference & on the way home from work the lower hose on right hand side of engine (looking from front) has given out & lost all coolant from a split in that. Luckily was within spitting distance from home & coasted to driveway

The water is a rusty orange colour so hoping the radiator is blocked? But would this result in the high pressure?

Have had a sniff test done & indicates head gaskets are ok. Any help or advise would be greatly appreciated

Thank you
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(Post Link) post #3 of 26 Old 28-07-09 Thread Starter
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What does the condition of the rad look like in general? Try flushing it through with a hose pipe and see a) what the flow is like and b) how much crud comes out. Sorry I'm not much help but I have never had this issue.
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The orange colour is most likely just the colour of your coolant.
Unlikely for the rad to be blocked, but have you checked the condition of the back of the rad?
Look for fins collapsing and falling out with the lightest touch.

You also need to make sure that both fans work on low speed and high speed.
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(Post Link) post #6 of 26 Old 28-07-09 Thread Starter
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Thanks for that

Back of rad looks fine a bit of green / blue corrosion in one small area & fins look fine none loose to touch.

The fans have always worked strange to me as within a couple of minuites from cold start up they fire up, they deff are working at high speed when the car is warm.

Do you know if an air lock would cause the high pressure causing the hose to give way?
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The fans running when cold is normal if the A/C is on.
Important that they also work at low speed before switching to high speed.
When the temp rises, the ECU will call for the low speed fan to control it. If that isn't working the temp will continue to rise until it gets so high that the ECU calls for the high speed fan.

The pressure cap should open before any hoses fail though...
Was the new cap the same spec as the original?
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(Post Link) post #8 of 26 Old 28-07-09 Thread Starter
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Yes cap was identical, i think maybe the garage that fitted the thermostat might have something do do with the hose failing as they had it off to fit the new stat I can feel a split in the pipe where it has gone. They orig looked at the car when I asked them to drain, flush & refill the system as I had lost some coolant with the origional cap (which I thought would be a simple job), When I picked it up they said that they could not get rid of an air lock & recommended a new thermostat. After which they fitted they then told me my head gasket has probably gone & the thermostat had not solved anything. I still had the airlock because I could feel the hoses were empty.

We have got a sniff test kit here so I checked that & the result was good no gasses in coolant.

Last edited by alfa3.2v6; 28-07-09 at 13:01.
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An airlock will cause problems and it shouldn't be that difficult for an experienced person to bleed the system properly.


PS, coolant should be red type.
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Two identical threads on this now....

Main thread is in the 147/156/GT section.
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(Post Link) post #11 of 26 Old 28-07-09 Thread Starter
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Yeah that was what I was thinking.... stuck with a lovely car that I can't use sitting on the driveway so depressing.

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Threads merged. Please do not cross post.
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(Post Link) post #13 of 26 Old 28-07-09 Thread Starter
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ok sorry about that wasnt sure where was best to post my problem
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What about the resistor that controls the lower speed of the fan to come on?
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(Post Link) post #15 of 26 Old 29-07-09 Thread Starter
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havent tried that both fans speeds seem to work ok, cars at alfashop now should know more tommrow hopefully they will do the business
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My Diagnosis would be that the water pump has failed. If it can't pump water it'll sit there getting hotter and hotter, hence the pressure build up.
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If the system was leaking coolant out of the cap, then it's because the pressure inside the system had passed 1.4 Bar (blue cap is it?) or whatever pressure is needed to activate the release valve.

You ONLY get high pressure in the system if there is gas in it, so;

1) You have an air-lock, or

2) You have a head gasket problem.

Forget the fan(s) ... your fans work. The car overheats because it has no coolant in it, or can't circulate what it does have. Any further discussion about fans is irrelevant.

The hose being split could be a result of the pressure in the system... more likely it was damaged by being taken off (if I read that right) .. the standard clips are not easy to remove and probably the metal cut the hose which was then weak and split under pressure.

So:

Job Number 1: Replace the hose. Use new clips.

Job Number 2: Get the air out of the system. With a cold engine (Saturday morning job) take the cap off the reservoir and squeeze the hoses. This will tell you if the hoses are empty or not (you'll feel the coolant in the hoses and the reservoir level will go up and down as you squeeze).

Add a 50:50 mix of coolant and water (use the same colour stuff as you have in there now.. probably the new pink stuff. Don't mix green/blue and pink types). Pour it into the reservoir so the level rises to about 1" off the Max mark. Squeeze the hoses.. that'll suck coolant into the bowels of the system. Add more coolant to that minus-1" point.

If there is a radiator bleed screw on the back of the rad (top left or top right) loosen it off slowly until air or coolant comes out. One or the other WILL come out. If/when coolant comes out, the rad' is bled. Don't take the screw all the way out, otherwise when coolant comes ******* out, it'll be difficult to put the screw back in. It's not fatal.. just messy.

Add more coolant to that minus-1" point. Squeeze the hoses some more. The level in the reservoir should drop and you should hear the coolant being sucked in to the system. When the level doesn't drop any more, we're almost done.

With the cap off, start the engine and set the heater to MAX and put the fan on. This will make coolant circulate through the heater and push any air out of there. Leave it for a few minites until warm air starts to come out of the heater. Job done. Turn the engine off.

Top up the reservoir to Max. Replace the cap. Have a cup of tea and a bacon sarnie.

Start the beast up and take it for a short drive. Don't go tooooo far in case it blows up but drive around enough for the car to warm right up. Open the heater as well.. give the system a good work out. Make sure the beast doesn't overheat.. but also that it warms up and stays warmed up (neither too cold or too hot.. i.e. working properly).

Arrive home, leave the engine running while you put the kettle on and wait until the fan comes on. Switch off, have a cup of tea and let the beast cool right down.

Many hours later (stone cold engine) have a peak under the bonnet. Coolant should be at Max still, though if it isn't take the cap off and top it up a bit. There should be no coolant leaked out of the reservoir cap and no leaks anywhere (especially hoses etc.). Repeat the quick drive around to warm it up and then let it cool down again until the coolant doesn't go down any more.

If the coolant is being pushed out of the cap still, there is still gas in the system. When the beast is still hot, touch the rad (don't put your fingers through the fan) to see if it's cold. If it is, when the engine cools down, bleed the radiator again and top up the coolant.

Basically you want to get it to a stable condition, repeating the bleed-top up-drive routine until the beast is sorted (should take one or two attempts) or it becomes clear you keep getting a gas lock.

Persistent gas lock would suggest a head gasket. You won't always get the CO detector giving you an indication as the ECU will be doing a fine job of burning whatever's in there. My h/g had a split 4" long in it and that didn't give any gas-in-coolant indication.

Hopefully it's just a combination of not-properly bled/topped up system that a quick tinker can sort. The system is self purging of air, so in theory at least it's a simple job to get air out.

Waterpump: I don't think so, yet. There's so many other variables that are way more likely.

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Quote:
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Many hours later (stone cold engine) have a peak under the bonnet. Coolant should be at Max still
At that point it is worth removing the cap, even if the level looks ok, because sometimes the level won't drop until the cap is removed.
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(Post Link) post #19 of 26 Old 06-08-09 Thread Starter
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Ralf

Thanks for the extensive post m8, i have been told my front headgasket has gone, caused by the water pump being split I never let the car get hotter than just over 90 deg - cant believe they still use plastic water pumps given the heap of s**t they have caused with the oldercars, never used the ash tray as its not a smoked in car, no doubt when i look its a choclate ashtray anyway .... lost all heart in alfas now , I love the look 100% main reason i brought the car - but wondering now if an m3 lump would fit in there somehow, then were talking! certainly different
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M3's suffer bore wear issues so they ain't perfect. BM sometimes fix it foc, sometimes not, especially if it's been serviced outside the dealer network.
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I only say that because i had one from a year old b4 the gt done 170k miles no problems whatsoever with the engine. Just found a rear ended 2009 right off one with 2k miles on the clock...v tempted
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One thing to add Ralf - sometimes the caps are known to lose their ability to seal. So it makes it look like something serious is wrong when in reality you just need a new coolant tank cap.
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Quote:
Originally Posted by alfa3.2v6 View Post
I only say that because i had one from a year old b4 the gt done 170k miles no problems whatsoever with the engine. Just found a rear ended 2009 right off one with 2k miles on the clock...v tempted
It'd be easier to squeeze the V8 in than the straight 6 I imagine.

But you are talking serious work. You would need to cut away chassis etc, you couldn't use the Beemer engine in FWD format.
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yeah i know it would be a challenge, we run 3 L200 pick ups in my company 2 have now got transit engines in, because the l200 engines are as im sure anyone that has one knows they are a bad lumps, i know i can make it work & do a good job just a time factor really, would certainly be a big job with the space issues & RWD etc but anythings possible, i probably wont be liked on here for doing it but i doooo like anything different which was what tempted me to the alfa side in the first place..

Last edited by alfa3.2v6; 06-08-09 at 22:41.
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I'd still like you if you did it.
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