Now this is a curiouis one...Coolant over pressure and overheat....

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Saint.V8 said:
The amount of pressure was no where near as much as it has been, but after sitting for 12 hours+ I wouldn't have thought there would be any pressure....

One thing is good, means there is no leaks as it hold pressure!!!!

Just something is causing an air lock and/or pressure.

Could it be still water in the engine block turning to steam...still water caused by weak pump flow??

Water pump seems capable of moving water as witnessed by the weep hole and bleed screw on the tank!
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Gas dissolved in the coolant coming back out? No idea if that is possible though.
It's turning into a real dog I'm sorry to say.
 
Saint.V8 said:
Well......

Got to the car this morning, decided to check the coolant level....undid the cap and there was a hiss and then about half a litre of coolant bubbled out, this is after standing for over 12 hours overnight!

The tank was full of water, opened the bleed screw and the level dropped right down, so filled up with a litre or so and did my best at 6am in the morning rain and wind to bleed the system.

Last night on the way home, she was 2-3degC warmer than usual (no stat fitted) but nothing untoward, on the way to work this morning with the heater full on, the temp of the airflow varied with engine speed.....

Considering changing the water pump (again - last changed 18 months or so ago) and see if that changes things!

If it isn't that, I will do a CO2/CO test on the expansion tank and see what gives....
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Mmmm, why not, seeing its the weekend, take the plugs out before you release the cap. If any pressure is released when taking the plugs out and there is no pressure in the header tank then it would point to head gasket or head fault. Or go for the co2/co test first. Good luck :)
 
I had something similar happen with an old Hilux when the head had cracked. That thing passed a sniff test too, but once the head was off you could see the cracks with the naked eye.

Not sounding good for you dear boy.
 
Bix said:
I had something similar happen with an old Hilux when the head had cracked. That thing passed a sniff test too, but once the head was off you could see the cracks with the naked eye.

Not sounding good for you dear boy.
Click to expand...

Cheers Bix....made my day lol :D:D:D:D:D:D

Got home and opened bonnet to feel hoses...not solid, firm, but not excessively and the temp was hovering in the 78-84degC range (No Stat fitted)

Will see what happens, may do Alans suggestion and whip the plugs and see if one is washed or if there is a pressure release.

Not relishing the idea of doing HG's on the M62 as the VANOS and locking of the Cams is quite an involved job requiring special locking tools, so plenty of research is required if I am to even attempt that one.

Luckily we have a good machinist at work who can turn most things so if I get stuck, no doubt he can help make stuff for me as I will be doing the job at work due to more space and ease of access to more tools than I own etc.
 
Hi Saint,
sorry its still playing up, for what its worth mine will hold pressure in the ET over several days, I have a 140 cap - which was a replacement for a 200. I would have thought that a HG would really push the coolant out as gases are very compressed from the action of the piston. I wondered if the removal of the thermostat had changed the flow of the water system and may cause a problem rather than solve one, but I'm not sure of the flow around the engine bay - the P38 manual shows it I believe, but not the 322, maybe there's a BMW doc out there. Its a reall pity that theres no real way to check the flow of the pump which doesnt involve dumping the coolant out of the engine, but personally I think that your problem may be there as your LPG system is out of circuit and you've changed just about everything else. Last thing, and it may be of no consequence, do you have demineralised water in your coolant? Only reason being the P38 manual is very specific about it and I'm not sure why but maybe its to do with the efficiency of the coolant? Good Luck and hopefully something other than HG comes to light.
 
forthbridge said:
Hi Saint,
sorry its still playing up, for what its worth mine will hold pressure in the ET over several days, I have a 140 cap - which was a replacement for a 200. I would have thought that a HG would really push the coolant out as gases are very compressed from the action of the piston. I wondered if the removal of the thermostat had changed the flow of the water system and may cause a problem rather than solve one, but I'm not sure of the flow around the engine bay - the P38 manual shows it I believe, but not the 322, maybe there's a BMW doc out there. Its a reall pity that theres no real way to check the flow of the pump which doesnt involve dumping the coolant out of the engine, but personally I think that your problem may be there as your LPG system is out of circuit and you've changed just about everything else. Last thing, and it may be of no consequence, do you have demineralised water in your coolant? Only reason being the P38 manual is very specific about it and I'm not sure why but maybe its to do with the efficiency of the coolant? Good Luck and hopefully something other than HG comes to light.
Click to expand...
Mineralised water is free of Chlorine, Calcium Carbonate (Limescale) and other potential sorces of corrosion and unwanted deposits.
 
UPDATE:

OK car hasn't run or moved since Friday evening, so this morning I checked the level and the tank was up to the neck (no hiss) but the water over flowed from the tank.

Open the bleed screw, and the level drops all the way back to normal level.....the bleed screw is part of the tank and is connected to the radiator overflow hose that allows coolant to expand into the tank.

Drove to work (26 miles) and left to cool, just checked and the coolant level is again up to the to of the tank neck, open bleed screw and it drops back to normal with a few gurgles.....

So there is an air pocket at the top of the radiator that isn't dissipating when the engine cools, this creates the air lock which I am having issues with.

I am currently running without a stat, but I am sure this wouldn't cause the air lock.

Could it be the expansion tank cap??

Might see if I can get a replacement today and see what happens.

Thoughts??
 
Saint.V8 said:
UPDATE:

OK car hasn't run or moved since Friday evening, so this morning I checked the level and the tank was up to the neck (no hiss) but the water over flowed from the tank.

Open the bleed screw, and the level drops all the way back to normal level.....the bleed screw is part of the tank and is connected to the radiator overflow hose that allows coolant to expand into the tank.

Drove to work (26 miles) and left to cool, just checked and the coolant level is again up to the to of the tank neck, open bleed screw and it drops back to normal with a few gurgles.....

So there is an air pocket at the top of the radiator that isn't dissipating when the engine cools, this creates the air lock which I am having issues with.

I am currently running without a stat, but I am sure this wouldn't cause the air lock.

Could it be the expansion tank cap??

Might see if I can get a replacement today and see what happens.

Thoughts??
Click to expand...

Well here's a straw to be grasped at, try backing up a set of ramps to put the header tank much higher than the rad top.:)
 
I seem to recall that some cars need some sort of pressurised filling system e.g by having a raised vessel to feed the water into the system and thereby forcing any air out of the coiling system as it fills

I have no idea whether this would be feasible or practicable on the L322 but it may be worth thinking about.

Pete
 
wil2813 said:
good call ant, bit like a kettle in the kitchen tbh open the lid & switch on & it will eventually boil itself dry or simply close the lid & it switches off when up to temp
Click to expand...

It isn't leaking , it is over pressurising....

i.e. As mentioned above, tank full of water, open bleed screw and with a few gurgles the level drops back down....it is as if there is an air pocket in the top of the rad, so when you open the bleed screw, the air is released and the coolant can drain back down the line in to the rad!
 
FURTHER UPDATE:

Well tried the CO2 test twice, once while sitting at work after switch on and getting up to temp....nothing! Tried for 25 minutes...still nothing

I even then went round to the exhaust just to test the fluid was OK...yep suck up some exhaust gas and the colour chages...

So drove home and just done the same again this time with a 26 mile run of Motorway, dual carriage way and traffic ........ done the same, no colour change...

Am I the only person in history to be pee'd off that my head gaskets appear to be OK?????

For two reasons:

1. Running out of reasons for this annoyance
2. Was kinda looking forward to striping the M62TU engine and writing a mammouth How To for you guys!!

So, next plae to look is the rear manifold and heater hoses and see if they are drawing air in!

Photos attached, note the coolant round the expansion tank cap is from the bleed screw!
 

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Looks like you have discovered how to turn petrol into water, it's the only answer. You could sell it to the Arabs, they have plenty of petrol and not enough water.
 
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