I think I've blown it
Discussion
Head gasket that is
Pretty certain I've blown a head gasket but I'm experiencing some strange running symptoms which I'm hoping the collective knowledge of this forum can shed some light on
Quick rundown:-
Couple of months back I overheated the wedge , a hose went and the temp shot up to about 110. Pulled over, allowed engine to cool, made a temp repair, topped up water and got home and replaced hose
Now to my odd running behavior
Car starts from cold with no problem, after a minute or so the car starts to misfire a little, slowly getting worse and worse until after 3-4 minutes of running its really bad running on any number of cylinders except the full 8 - sometimes the engine will die altogether for 1/2 a sec then fire up again just before stalling
However if I keep the engine running for another minute or so by keeping the revs up at about 2500rpm the rough running will all of a sudden just disappear and the car will run beautifully.
If I stop and let the car cool then no problem on start up but if the car is left to stand overnight the issue returns
No water in oil
No oil in water
Losing water some of which is due to a seeping hose but I suspect not all of it
My guess is I've done the head gasket between a water gallery and a cylinder (or more) but cant get my head round why the running issues disappear after a few minutes? And when they disappear its like someone's just flicked a switch its almost instantaneous
Dont think I'm going to get a chance to investigate for a while due to work and domestic obligations but was just wondering what you Gentlemen thought of it all ??
Tia for replies
Ron
Pretty certain I've blown a head gasket but I'm experiencing some strange running symptoms which I'm hoping the collective knowledge of this forum can shed some light on
Quick rundown:-
Couple of months back I overheated the wedge , a hose went and the temp shot up to about 110. Pulled over, allowed engine to cool, made a temp repair, topped up water and got home and replaced hose
Now to my odd running behavior
Car starts from cold with no problem, after a minute or so the car starts to misfire a little, slowly getting worse and worse until after 3-4 minutes of running its really bad running on any number of cylinders except the full 8 - sometimes the engine will die altogether for 1/2 a sec then fire up again just before stalling
However if I keep the engine running for another minute or so by keeping the revs up at about 2500rpm the rough running will all of a sudden just disappear and the car will run beautifully.
If I stop and let the car cool then no problem on start up but if the car is left to stand overnight the issue returns
No water in oil
No oil in water
Losing water some of which is due to a seeping hose but I suspect not all of it
My guess is I've done the head gasket between a water gallery and a cylinder (or more) but cant get my head round why the running issues disappear after a few minutes? And when they disappear its like someone's just flicked a switch its almost instantaneous
Dont think I'm going to get a chance to investigate for a while due to work and domestic obligations but was just wondering what you Gentlemen thought of it all ??
Tia for replies
Ron
Ron, do a Hydro carbon test on the coolant I have a kit if you need to borrow, but your local Indie will do it for you, then a compression test to eliminate those from your enquiries. Then look at the other simple fault finding processes ... Cooking of the coolant system can destroy or cause odd behaviour from the engine temp sensor 
Long time no see matey trust you are all well?
C
Long time no see matey trust you are all well?
C
Hi Ron,
My guess would be that you have air/gas in the cooling system. The temperature sender that the ECU uses to control the fueling is one of the highest points on the engine; and if the temperature sender is not immersed in coolant it will read low even if the engine is overheating. So... cold start is OK as the sender is at ambient temperature; as the engine warms up the sensor reads too low as it's not immersed in coolant so the engine splutters and dies as it has too much fuel; if you rev it the water pump pushes enough water around the system to purge out the air so the sensor is now reading the true engine temp so the engine gets the right amount of fuel.
Next question is why you have air in the cooling system... could be a blown head gasket or could be it needs 'burping'. I'd look for other signs of a blowing head gasket ie over-pressurisation of the coolant (feel the hoses as it warms up) and blowing coolant out of the expansion tank overflow. Fingers crossed... could just be a leak somewhere which was made worse when it blew a hose off.
Good luck! Martin
My guess would be that you have air/gas in the cooling system. The temperature sender that the ECU uses to control the fueling is one of the highest points on the engine; and if the temperature sender is not immersed in coolant it will read low even if the engine is overheating. So... cold start is OK as the sender is at ambient temperature; as the engine warms up the sensor reads too low as it's not immersed in coolant so the engine splutters and dies as it has too much fuel; if you rev it the water pump pushes enough water around the system to purge out the air so the sensor is now reading the true engine temp so the engine gets the right amount of fuel.
Next question is why you have air in the cooling system... could be a blown head gasket or could be it needs 'burping'. I'd look for other signs of a blowing head gasket ie over-pressurisation of the coolant (feel the hoses as it warms up) and blowing coolant out of the expansion tank overflow. Fingers crossed... could just be a leak somewhere which was made worse when it blew a hose off.
Good luck! Martin
Afternoon all
Finally found a a bit of time to look at the wedge
Sorted the water leak - what was just a "seep" from a hose soon turned into a lot worse once the car warmed up and the system fully pressurised
All sorted once I took the hose off cleaned everything up and put it back with some nice new hose clips
Martin you were correct with you're diagnosis - thank you
Once I sorted the leak I fully refilled the cooling system - instead of refilling just from the expansion tank I also took off the blank from the swan neck and refilled from there also - it's amazing how much more water I got into her - and just when you think your done a little bubble of air will pop to the top and you have to put a bit more in.
As you said Martin the CTS must have been sitting in an air pocket causing some horrible running then once the thermostat opens and coolant starts to flow round the system normal service is resumed.
Any how all sorted on that front just need some good weather and a bit of time to sort the other issues - bit of vibration (uj's I think) my v-e-r-y s-l-o-w electric windows ,oh and mot due in 3 weeks
Thanks fellas
Finally found a a bit of time to look at the wedge
Sorted the water leak - what was just a "seep" from a hose soon turned into a lot worse once the car warmed up and the system fully pressurised
All sorted once I took the hose off cleaned everything up and put it back with some nice new hose clips
Martin you were correct with you're diagnosis - thank you
Once I sorted the leak I fully refilled the cooling system - instead of refilling just from the expansion tank I also took off the blank from the swan neck and refilled from there also - it's amazing how much more water I got into her - and just when you think your done a little bubble of air will pop to the top and you have to put a bit more in.
As you said Martin the CTS must have been sitting in an air pocket causing some horrible running then once the thermostat opens and coolant starts to flow round the system normal service is resumed.
Any how all sorted on that front just need some good weather and a bit of time to sort the other issues - bit of vibration (uj's I think) my v-e-r-y s-l-o-w electric windows ,oh and mot due in 3 weeks
Thanks fellas
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