parchwba
Active Member
Cheers Mark, I did notice today as the engine was warming up that the top right hand hose was getting warm (as it should), but not at the top. That would suggest that (like a rad in the house), theres no water at the top of the hose where its joined to the rad. Is this an air lock then?
I'll run it tomorrow and do as you say to see if any water is coming from pipe in the expansion tank.
The top right hand pipe connected to the rad was cold. Didn't have time to see if it got warm though. Will check that also.
I'll run it tomorrow and do as you say to see if any water is coming from pipe in the expansion tank.
The top right hand pipe connected to the rad was cold. Didn't have time to see if it got warm though. Will check that also.
parchwba
Active Member
Have you touched the thermostat recently, there is a little bleed hole that should be at the twelve o'clock position.
Did you check the sensors under the manifold?
Did you check the sensors under the manifold?
Madmustang
Well-Known Member
Some times what I do is start the car with the filler cap off and let it self-bleed. be careful not to let the water get too hot. Put cap back on and let it cool then repeat. See how you get on and you may have to top-up with the prober mix. I used to just top up with water and I was constantly filling up every day until I did a rad flush and topped it up with the prober mix. Now I only top up every few months.
You need someone with a static tester. Couple up with engine cold and coolant at correct cold level. Watch how the pressure rises as the engine warms. At normal temp there should be around five to seven PSI on the gauge. With the engine cold there should be no pressure at all in the system. Are you sure you are getting pressure release when cold or air being sucked. I would think that if it is pressure release the engine would have boiled over before now.
parchwba
Active Member
Not been able to get to work on car today. But you mentioning this, I think I've read somewhere that about topping it up whilst the cap is open and engine running. Will hide away keys and try in the morning.
parchwba
Active Member
When I release the cap the coolant rises about 2cm. So I assumed the hissing was pressure coming out.
To me that is a sign of an issue. Now I'm not an expert on diesels but in that respect ie pressure when cold there simply shouldn't be any. None. If there is it points to a fairly serious issue. I don't think pressure like that could come from any simple airlock . Mine did not test positive using a block test either? But as soon as the issue was sorted no pressure.
parchwba
Active Member
Found coolant bottom near side of rad but not the leak itself. I suppose therefore the leak is somewhere behind the intercooler?
Ran engine with expansion cap off to bleed the system. Some air came from the overflow pipe but then was ok. However, lots of little bubbles forming in the expansion tank. Is this what is causing the pressure build up in the system? Are those air bubbles coming from a blown head gasket? They stop forming when engine is off.
Coolant leak is intermittent and very slight. could be to do with pressure in the system?
Ran engine with expansion cap off to bleed the system. Some air came from the overflow pipe but then was ok. However, lots of little bubbles forming in the expansion tank. Is this what is causing the pressure build up in the system? Are those air bubbles coming from a blown head gasket? They stop forming when engine is off.
Coolant leak is intermittent and very slight. could be to do with pressure in the system?
Can you smell exhaust like fumes when you sniff the expansion tank?
Try a block test. They are pretty sensitive and involve sucking air from the expansion tank and bubbling it through an indicator. My liners had dropped 2 thou so it was loosing coolant pressure in tank and odd cooling not to mention slight water in oil. But it certainly wasn't drastic as it was a new gasket with only 2 thou gap. Yours sounds slightly more advanced as I guess an old and worn gasket would be so may be a block test will show issues.
Jb
Jb
The air is getting in from somewhere!
It would seem your head gasket is starting to leak air in the system.
I take it you've checked the dipstick near the top and the oil cap for mayonnaise.
Even if they are just oily your gasket can pass air from a cylinder into a water way.
As you know if the gasket goes between a water way and an oil way you get mayonnaise! But not always if it is the start of a very small breakdown in the gasket.
If you have pressure in the system after it has been run then it shows your system has been pumped up by something!! Even a tiny hole or track burnt into the head or gasket can lead to pressure in the system... Before committing to a strip down of the head you may need a second opinion so you are a 100% sure.
I had a vauxhall omege 2.0 petrol that had the same issue. Ran for ages like that then one day it jumped up the temp gauge. This followed by dirty coolant with little bits of dust (if you like) floating around in it... After lifting the head there was a tiny track burnt between the cylinder and a water way. No mayonnaise on the cap or dipstick...
Now for the rad. On my bus the radiator was changed every year for two years before I owned it. It has a deeper intercooler on it. When it was fitted the welds in the alloy were rubbing through the fins on the radiator. Also they hadn't bolted the bottom of the rad so it was all moving!!!
You need a second opinion or... You could wait (at risk), to see if it gets worse...
It would seem your head gasket is starting to leak air in the system.
I take it you've checked the dipstick near the top and the oil cap for mayonnaise.
Even if they are just oily your gasket can pass air from a cylinder into a water way.
As you know if the gasket goes between a water way and an oil way you get mayonnaise! But not always if it is the start of a very small breakdown in the gasket.
If you have pressure in the system after it has been run then it shows your system has been pumped up by something!! Even a tiny hole or track burnt into the head or gasket can lead to pressure in the system... Before committing to a strip down of the head you may need a second opinion so you are a 100% sure.
I had a vauxhall omege 2.0 petrol that had the same issue. Ran for ages like that then one day it jumped up the temp gauge. This followed by dirty coolant with little bits of dust (if you like) floating around in it... After lifting the head there was a tiny track burnt between the cylinder and a water way. No mayonnaise on the cap or dipstick...
Now for the rad. On my bus the radiator was changed every year for two years before I owned it. It has a deeper intercooler on it. When it was fitted the welds in the alloy were rubbing through the fins on the radiator. Also they hadn't bolted the bottom of the rad so it was all moving!!!
You need a second opinion or... You could wait (at risk), to see if it gets worse...
I did a vacuum test on a Renault diesel. That engine showed a leak in the gasket after I could hear it drawing in air!!
I agree. You need a definite result!
tomcat59alan
Well-Known Member
Sounds ominously like the symptoms I started with. After the bolt that holds the metal heater pipe to the front cover decided to do a vanishing trick, it overheated. New bolt,loctited in, and a new O ring I thought I had got away with it. Then the top of the radiator split!. I seemed to be loosing a little coolant so kept topping it up until, one morning it hydraluliced. When it started it ran perfectly and the temperature remained at 12 o clock including a blast down the motorway at 70 ish+ vat. The following morning the level had dropped a bit and the same locking up.The next day I took the heater plugs out,got the Enemy to turn it over while I held rags over the plug holes.I got bloody soaked! Great compressions blew the rags out of place and a load of water out of number 3.So, state of play is I've stripped the engine, and when I get the replacement head back from the engineers after pressure testing,I'll rebuild it already fitted the new timing chains.
