V8 - Possible head gasket leak
Discussion
i had the same problem 2 years ago on my 350i, loss of coolant while hot and pressurising forcing coolant out of the overflow on the header tank, also i did have the bubbles in the header tank after revving the engine and letting it idle back, the other sign of the head gasket gone was foaming in the header tank as well.
adam quantrill said:
Thanks for the suggestions. I don't know if a compression test will necessarily show anything - I have a gauge and will try it but if the leak isn't huge then the compression may just be within normal tolerances.
I'll have a sniff of the coolant but haven't noticed any foaming.
Hi Adam..When my head gaskets was failing on the 280 i had no foaming..The compression test showed no abnormalities but i was losing coolant but couldnt see where..It would overheat if i sat in traffic and the header tank smelt highly of fumes..Although i didnt think it did..There were hydrocarbons in the coolant even after topping up...A good garage should have a calibrated tester with clean fluid..ZigaI'll have a sniff of the coolant but haven't noticed any foaming.
I had a blown HG about 3 years ago on the 400. No coolant pressurisation or loss, although you could hear that something wasn't right - it sounded like a manifold / pipe blow. When I got it apart, the gasket had failed without hitting a waterway (due to a stripped HG stud) which had taken several years to manifest itself.
Even simpler - just did a test on mine using common household ingredients and a vague recollection of my chemi O level.
So - with the engine running on old it wasn't outputting any foam but there was the odd bubble of gas. On mine the header tank is connected to the swan neck via one pipe only - it's a bit of an odd arrangement.
Anyhow I put the pressure cap back on and ran it for a few minutes at 2000 rpm, and it did start putting bubbles of gas down the pipe to the overflow (catch) tank - but what was this gas?
A rudimentary knowledge of combustion shows that any gases produced in the cylinders will be mainly CO2, CO forming a small proportion, so that's what I set out to detect.
Luckily my house is made if s
t and sticks being 400 years old so I have a handy supply of lime for any patching up. Put a teaspoon of lime into a jam jar, shake it up, leave it for 5 mins then filter gives you clear lime water. Then I bubbled the gas from the overflow pipe through this and hey presto - it turned milky clearly showing the presence of CO2.
I didn't even bother getting the compression tester hooked up, it's fairly clear cut.
So - where to get composite head gaskets (I reckon these will work well with the engine being supercharged 'n' all) and do I change the cam at the same time as it's approaching 60k miles?
RPI do some for £35 a pair for 94mm bore engines which I guess this is, it being 4l, plus I'll need a valley gasket and the rubber seals I expect.
It's been a while since I did this I know the inlet manifold has to come off but can I leave the plenum cover on it in situ? Also do you think I can get away with leaving the exhaust manifolds attached to the heads - just want to disturb the minimum possible...
So - with the engine running on old it wasn't outputting any foam but there was the odd bubble of gas. On mine the header tank is connected to the swan neck via one pipe only - it's a bit of an odd arrangement.
Anyhow I put the pressure cap back on and ran it for a few minutes at 2000 rpm, and it did start putting bubbles of gas down the pipe to the overflow (catch) tank - but what was this gas?
A rudimentary knowledge of combustion shows that any gases produced in the cylinders will be mainly CO2, CO forming a small proportion, so that's what I set out to detect.
Luckily my house is made if s
t and sticks being 400 years old so I have a handy supply of lime for any patching up. Put a teaspoon of lime into a jam jar, shake it up, leave it for 5 mins then filter gives you clear lime water. Then I bubbled the gas from the overflow pipe through this and hey presto - it turned milky clearly showing the presence of CO2.I didn't even bother getting the compression tester hooked up, it's fairly clear cut.
So - where to get composite head gaskets (I reckon these will work well with the engine being supercharged 'n' all) and do I change the cam at the same time as it's approaching 60k miles?
RPI do some for £35 a pair for 94mm bore engines which I guess this is, it being 4l, plus I'll need a valley gasket and the rubber seals I expect.
It's been a while since I did this I know the inlet manifold has to come off but can I leave the plenum cover on it in situ? Also do you think I can get away with leaving the exhaust manifolds attached to the heads - just want to disturb the minimum possible...
adam quantrill said:
Even simpler - just did a test on mine using common household ingredients and a vague recollection of my chemi O level.
So - with the engine running on old it wasn't outputting any foam but there was the odd bubble of gas. On mine the header tank is connected to the swan neck via one pipe only - it's a bit of an odd arrangement.
Anyhow I put the pressure cap back on and ran it for a few minutes at 2000 rpm, and it did start putting bubbles of gas down the pipe to the overflow (catch) tank - but what was this gas?
A rudimentary knowledge of combustion shows that any gases produced in the cylinders will be mainly CO2, CO forming a small proportion, so that's what I set out to detect.
Luckily my house is made if st and sticks being 400 years old so I have a handy supply of lime for any patching up. Put a teaspoon of lime into a jam jar, shake it up, leave it for 5 mins then filter gives you clear lime water. Then I bubbled the gas from the overflow pipe through this and hey presto - it turned milky clearly showing the presence of CO2.
I didn't even bother getting the compression tester hooked up, it's fairly clear cut.
So - where to get composite head gaskets (I reckon these will work well with the engine being supercharged 'n' all) and do I change the cam at the same time as it's approaching 60k miles?
RPI do some for £35 a pair for 94mm bore engines which I guess this is, it being 4l, plus I'll need a valley gasket and the rubber seals I expect.
It's been a while since I did this I know the inlet manifold has to come off but can I leave the plenum cover on it in situ? Also do you think I can get away with leaving the exhaust manifolds attached to the heads - just want to disturb the minimum possible...
A mate of mine was a chemist, he isn't any moreSo - with the engine running on old it wasn't outputting any foam but there was the odd bubble of gas. On mine the header tank is connected to the swan neck via one pipe only - it's a bit of an odd arrangement.
Anyhow I put the pressure cap back on and ran it for a few minutes at 2000 rpm, and it did start putting bubbles of gas down the pipe to the overflow (catch) tank - but what was this gas?
A rudimentary knowledge of combustion shows that any gases produced in the cylinders will be mainly CO2, CO forming a small proportion, so that's what I set out to detect.
Luckily my house is made if s
t and sticks being 400 years old so I have a handy supply of lime for any patching up. Put a teaspoon of lime into a jam jar, shake it up, leave it for 5 mins then filter gives you clear lime water. Then I bubbled the gas from the overflow pipe through this and hey presto - it turned milky clearly showing the presence of CO2.I didn't even bother getting the compression tester hooked up, it's fairly clear cut.
So - where to get composite head gaskets (I reckon these will work well with the engine being supercharged 'n' all) and do I change the cam at the same time as it's approaching 60k miles?
RPI do some for £35 a pair for 94mm bore engines which I guess this is, it being 4l, plus I'll need a valley gasket and the rubber seals I expect.
It's been a while since I did this I know the inlet manifold has to come off but can I leave the plenum cover on it in situ? Also do you think I can get away with leaving the exhaust manifolds attached to the heads - just want to disturb the minimum possible...
'cos what he thought was H2O was H2SO4
Plenum could stay in place but for the sake of 6 bolts and a smear of sealant it's no hardship to remove.
Exhaust manifolds might be more of a problem owing to the head studs; as the heads slide up they'll move outward so the manifolds probably won't clear the chassis/ side of the engine bay.
Of course if the heads are bolted rather than on studs it may not be an issue: why not try it and report back? I expect that the heads are bolted, in which case I was thinking of changing over to studs anyway to get better clamping. So I would be in the same boat.
An ARP stud kit is around £95 from the 'states but what is the difference with using standard studding cut to length? Standard studding is a few quid a metre which would come to around 20 sobs.
An ARP stud kit is around £95 from the 'states but what is the difference with using standard studding cut to length? Standard studding is a few quid a metre which would come to around 20 sobs.
adam quantrill said:
An ARP stud kit is around £95 from the 'states but what is the difference with using standard studding cut to length? Standard studding is a few quid a metre which would come to around 20 sobs.
At a guess, standard studding is made from monkey-metal and the real thing is high-tensile steel of known provenance and some quality control?I've seen studding on jobs at work what wasn't even round
adam quantrill said:
Even simpler - just did a test on mine using common household ingredients and a vague recollection of my chemi O level.
So - with the engine running on old it wasn't outputting any foam but there was the odd bubble of gas. On mine the header tank is connected to the swan neck via one pipe only - it's a bit of an odd arrangement.
Anyhow I put the pressure cap back on and ran it for a few minutes at 2000 rpm, and it did start putting bubbles of gas down the pipe to the overflow (catch) tank - but what was this gas?
A rudimentary knowledge of combustion shows that any gases produced in the cylinders will be mainly CO2, CO forming a small proportion, so that's what I set out to detect.
Luckily my house is made if st and sticks being 400 years old so I have a handy supply of lime for any patching up. Put a teaspoon of lime into a jam jar, shake it up, leave it for 5 mins then filter gives you clear lime water. Then I bubbled the gas from the overflow pipe through this and hey presto - it turned milky clearly showing the presence of CO2.
I didn't even bother getting the compression tester hooked up, it's fairly clear cut.
So - where to get composite head gaskets (I reckon these will work well with the engine being supercharged 'n' all) and do I change the cam at the same time as it's approaching 60k miles?
RPI do some for £35 a pair for 94mm bore engines which I guess this is, it being 4l, plus I'll need a valley gasket and the rubber seals I expect.
It's been a while since I did this I know the inlet manifold has to come off but can I leave the plenum cover on it in situ? Also do you think I can get away with leaving the exhaust manifolds attached to the heads - just want to disturb the minimum possible...
Bloody hell professor lol :-))So - with the engine running on old it wasn't outputting any foam but there was the odd bubble of gas. On mine the header tank is connected to the swan neck via one pipe only - it's a bit of an odd arrangement.
Anyhow I put the pressure cap back on and ran it for a few minutes at 2000 rpm, and it did start putting bubbles of gas down the pipe to the overflow (catch) tank - but what was this gas?
A rudimentary knowledge of combustion shows that any gases produced in the cylinders will be mainly CO2, CO forming a small proportion, so that's what I set out to detect.
Luckily my house is made if s
t and sticks being 400 years old so I have a handy supply of lime for any patching up. Put a teaspoon of lime into a jam jar, shake it up, leave it for 5 mins then filter gives you clear lime water. Then I bubbled the gas from the overflow pipe through this and hey presto - it turned milky clearly showing the presence of CO2.I didn't even bother getting the compression tester hooked up, it's fairly clear cut.
So - where to get composite head gaskets (I reckon these will work well with the engine being supercharged 'n' all) and do I change the cam at the same time as it's approaching 60k miles?
RPI do some for £35 a pair for 94mm bore engines which I guess this is, it being 4l, plus I'll need a valley gasket and the rubber seals I expect.
It's been a while since I did this I know the inlet manifold has to come off but can I leave the plenum cover on it in situ? Also do you think I can get away with leaving the exhaust manifolds attached to the heads - just want to disturb the minimum possible...
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