Blew the rad,and the headgasket!!
- Thread starter Pilkie
- Start date
Pilkie
Active Member
Never had a leaky inlet or exh valve cause pressurisation of the water system before,and make the water stink of headgasket failure!
I did a dry then wet compression test and all were in the 125-145 ball park,so it has to be a hairline crack,that possibly seals up or opens up when warm,and seeps water under pressure into a bore when it cools down.
It didnt like going to the shopsso theres still a problem.
Tomorrows another day,so will work the problem till I find evidence of the problem.
If it does seem to show that one head seems cracked I will put the spare good clean one on.
I did a dry then wet compression test and all were in the 125-145 ball park,so it has to be a hairline crack,that possibly seals up or opens up when warm,and seeps water under pressure into a bore when it cools down.
It didnt like going to the shopsso theres still a problem.
Tomorrows another day,so will work the problem till I find evidence of the problem.
If it does seem to show that one head seems cracked I will put the spare good clean one on.
One thing to remember Pilkie is that starting an engine with coolant down a cylinder can result in the associated connecting rod suffering permanent deformation. Water cannot in real terms be compressed, so do be very careful.
Ron.
Ron.
Just thinking aloud, I don't suppose you checked to see if any of the liners had dropped at all? If one has dropped, it won't be by much, but that would indicate that you have a crack in the block behind that liner. That will allow coolant into the cylinder and it will also pressurise the cooling system. It may not be probable with an early 3.5 block, but it is definitely not impossible.
Ron.
Ron.
Pilkie
Active Member
Am aware of the hydraulic lock possibility,just got to hope at the moment.
All liners were flush with the head,no sign of any of them dropping!
Anything that cant be seen is possible at the moment!
I would of preferred to have had at least some hint of seeing the problem,but there was nothing that said to me "Thats it"!!
All liners were flush with the head,no sign of any of them dropping!
Anything that cant be seen is possible at the moment!
I would of preferred to have had at least some hint of seeing the problem,but there was nothing that said to me "Thats it"!!
Oh dear!
Don't forget that the inlet manifold has water in it, so you can add that to the heads as a source of water going into the cylinders.
I'd want to be absolutely sure that the engine coolant system is pressurising. I'm not entirely clear that it is from what you've said so far.
I always uderstood that dropped liners tended to leak water from the bottom into the sump? Can anyone confirm or deny that?
Chris
Don't forget that the inlet manifold has water in it, so you can add that to the heads as a source of water going into the cylinders.
I'd want to be absolutely sure that the engine coolant system is pressurising. I'm not entirely clear that it is from what you've said so far.
I always uderstood that dropped liners tended to leak water from the bottom into the sump? Can anyone confirm or deny that?
Chris
Pilkie
Active Member
Just to confirm after my trip to the shop of 1 mile!
The system pressurises from cold and it is blowing the rad cap.
The pressure gets up quite quick,so that the water is prevented from circulating and opening the thermostat.
Water may get in from the inlet manifold via a valve,but as it sucks from there it shouldnt be the cause of pressure in the water,that has to be either the liner,headgasket,a cracked head and possibly on the exh outlet side!
Further investigation starts tomorrow.
I am off for a long soak in a very warm bubbly bath!!
The system pressurises from cold and it is blowing the rad cap.
The pressure gets up quite quick,so that the water is prevented from circulating and opening the thermostat.
Water may get in from the inlet manifold via a valve,but as it sucks from there it shouldnt be the cause of pressure in the water,that has to be either the liner,headgasket,a cracked head and possibly on the exh outlet side!
Further investigation starts tomorrow.
I am off for a long soak in a very warm bubbly bath!!
stina
New Member
Dave , real gut wrencher when you have put in so much work . Sometimes it's something small , overlooked . Had the head off my 1275 moggy three times , it was showing the same symptoms , turned out to be a brass casting bung leaking into the head ..
Why not try removing all the plugs in the morning , and dipping a cotton bud taped to a long stick down each pot to find the wet one , it'll let you know which one is the problem after it's been sat over night .
Good luck , keep us posted :?
Why not try removing all the plugs in the morning , and dipping a cotton bud taped to a long stick down each pot to find the wet one , it'll let you know which one is the problem after it's been sat over night .
Good luck , keep us posted :?
Could be that corrosion has perforated a coolant passage which is exposed to combustion or exhaust pressure. What type of coolant have you been using Pilkie, and how often have you changed it? Was the change interval within the recommended time or distance?
Ron.
Ron.
Pilkie
Active Member
Just a quick update.
After leaving the car overnight,removed plugs and with a suitable length of twisted tissue paper stuffed in the bores ive found no traces of water.
Did another compression test,and all are 135-145psi "book says 135psi",without adding a drip of oil "wet test",which normally increases the readings.
Fitted a tyre valve into a spare old top hose and pressurised to 20-25lbs,the rad cap blew bubbles into the expansion tank ive got fitted till the pressure got down to 13lb,so thats working ok.
Its possible that whatever is wrong only happens when it has warmed up a bit,so will warm it up and do the checks again.
:? :?
After leaving the car overnight,removed plugs and with a suitable length of twisted tissue paper stuffed in the bores ive found no traces of water.
Did another compression test,and all are 135-145psi "book says 135psi",without adding a drip of oil "wet test",which normally increases the readings.
Fitted a tyre valve into a spare old top hose and pressurised to 20-25lbs,the rad cap blew bubbles into the expansion tank ive got fitted till the pressure got down to 13lb,so thats working ok.
Its possible that whatever is wrong only happens when it has warmed up a bit,so will warm it up and do the checks again.
:? :?
Pilkie
Active Member
RIGHT!
We have a result of sorts!
Warmed engine up till pressure built up to 23psi,then the cap blew and it settled after a few mins to 13psi,ran it a bit longer till it built up again,removed plugs,and went for a cuppa.
When I came back I dipped all the bores with a long stiff but flexible pipe cleaner type object,"water probe",so it got down to the piston and curled up on top a bit.
All bores were dry,except for No4 of which the probe came out wet and steaming!
Went round all of them again to double check,No4 still wet and steaming.
Turned engine over with just the compression testers tube attached and out came a spurt of water and steam.
Then tested all compressions again,and all including No4 were 145-155psi.
I expected No4 to be down,but it was 155psi.
So now I can remove just that head and investigate further.
If I am correct,and those of you with more V8 experience please chip in.
This means that either No4 piston liner is at fault,or there is a crack in the head,as there is no water outlet close to be affected by a blown headgasket!?
As always your thoughts and ideas are appreciated.
There is a place nearby that can hot and cold pressure test the head for me,and I have the spare I could throw on and try.
If it turns out that,if I can detect it,that its the liner thats the fault,then I will be putting in the spare engine this week.
I have been considering the use of this product,or one similar!!
http://www.ebay.co.uk/itm/Rover-V8-Poro ... 56484205d9
What are your opinions???
Time for another cuppa and a sarnie!
And to have a read of this!!
http://www.v8engines.com/Acrobat/LRO_May_small.PDF
We have a result of sorts!
Warmed engine up till pressure built up to 23psi,then the cap blew and it settled after a few mins to 13psi,ran it a bit longer till it built up again,removed plugs,and went for a cuppa.
When I came back I dipped all the bores with a long stiff but flexible pipe cleaner type object,"water probe",so it got down to the piston and curled up on top a bit.
All bores were dry,except for No4 of which the probe came out wet and steaming!
Went round all of them again to double check,No4 still wet and steaming.
Turned engine over with just the compression testers tube attached and out came a spurt of water and steam.
Then tested all compressions again,and all including No4 were 145-155psi.
I expected No4 to be down,but it was 155psi.
So now I can remove just that head and investigate further.
If I am correct,and those of you with more V8 experience please chip in.
This means that either No4 piston liner is at fault,or there is a crack in the head,as there is no water outlet close to be affected by a blown headgasket!?
As always your thoughts and ideas are appreciated.
There is a place nearby that can hot and cold pressure test the head for me,and I have the spare I could throw on and try.
If it turns out that,if I can detect it,that its the liner thats the fault,then I will be putting in the spare engine this week.
I have been considering the use of this product,or one similar!!
http://www.ebay.co.uk/itm/Rover-V8-Poro ... 56484205d9
What are your opinions???
Time for another cuppa and a sarnie!
And to have a read of this!!
http://www.v8engines.com/Acrobat/LRO_May_small.PDF
Pilkie
Active Member
Right,suitably refreshed and articles read.
I had noticed at times a metallic tappety noise when running,that was there at start up and didnt really go away!!
I put it down to a weak hydraulic tappet,that got better as it warmed up.
Also noticed when it was stripped that No4 cam lobes were a little worn.
This leads me to the conclusion that,if both tappets on No4 were not working properly,it eventually wore the cam,and as the cam was worn,it weakened the mix in No4,thus allowing the piston to run too hot,which caused the block behind the liner to crack, allowing the liner to slip,and move up and down with the piston causing a tap,and caused the water system pressure and the leak into the bore.
Its very possible that when cold the liner is tight,and when I stripped it down was in the right position,so I suspected nothing!
Time to strip it down again and see whats what..
I had noticed at times a metallic tappety noise when running,that was there at start up and didnt really go away!!
I put it down to a weak hydraulic tappet,that got better as it warmed up.
Also noticed when it was stripped that No4 cam lobes were a little worn.
This leads me to the conclusion that,if both tappets on No4 were not working properly,it eventually wore the cam,and as the cam was worn,it weakened the mix in No4,thus allowing the piston to run too hot,which caused the block behind the liner to crack, allowing the liner to slip,and move up and down with the piston causing a tap,and caused the water system pressure and the leak into the bore.
Its very possible that when cold the liner is tight,and when I stripped it down was in the right position,so I suspected nothing!
Time to strip it down again and see whats what..
Pilkie
Active Member
K seal only lasted a couple of weeks,its had a few galls of water through it since then!
When i took it apart there was no trace of any Kseal indicating a poss leak point!
I am considering giving the black magic stuff,or this a try!
http://www.ebay.co.uk/itm/Irontite-Prof ... 3a51523c43
At least if it doesnt work I know its terminal,and I drop in the spare engine,if it does work and I get a few months out of it,thats enough time to clean and detail the spare engine,as was my intention to do one winter anyway.!!
Right gonna put the rover back in the corner of the carport,and play with the MG for a while!!
Fit the front engine bay panels and front wings,bolt down the tub,and the new wiring loom and all the new lights are in stock ready to be put in.
When i took it apart there was no trace of any Kseal indicating a poss leak point!
I am considering giving the black magic stuff,or this a try!
http://www.ebay.co.uk/itm/Irontite-Prof ... 3a51523c43
At least if it doesnt work I know its terminal,and I drop in the spare engine,if it does work and I get a few months out of it,thats enough time to clean and detail the spare engine,as was my intention to do one winter anyway.!!
Right gonna put the rover back in the corner of the carport,and play with the MG for a while!!
Fit the front engine bay panels and front wings,bolt down the tub,and the new wiring loom and all the new lights are in stock ready to be put in.
Pilkie wrote,...
It is usually the other way, when cold the liner will move, once hot it stays put. The aluminium alloy of the block expands at roughly twice the rate as the cast iron liner, so as the temperature rises so the pressure on the liner increases.
There could be corrosion within the coolant passage around that cylinder that has perforated both the aluminium alloy and eaten into the cast iron liner. That brings me back to the type of coolant that you have been using, what strength and how often it has been changed?
If the cylinder head is the culprit, then it could be cracked although that would not normally happen unless you boiled the engine, but even then not likely. Corrosion can eat through the coolant passage behind the exhaust valve which will allow coolant to flow into the cylinder, but when the valve is closed the coolant flow would be essentially prevented.
Ron.
It is usually the other way, when cold the liner will move, once hot it stays put. The aluminium alloy of the block expands at roughly twice the rate as the cast iron liner, so as the temperature rises so the pressure on the liner increases.
There could be corrosion within the coolant passage around that cylinder that has perforated both the aluminium alloy and eaten into the cast iron liner. That brings me back to the type of coolant that you have been using, what strength and how often it has been changed?
If the cylinder head is the culprit, then it could be cracked although that would not normally happen unless you boiled the engine, but even then not likely. Corrosion can eat through the coolant passage behind the exhaust valve which will allow coolant to flow into the cylinder, but when the valve is closed the coolant flow would be essentially prevented.
Ron.
Pilkie
Active Member
Due to the fact that ive been loosing a bit of water for a little while ive only put antifreeze "Bluecol",in when it starts to turn cold.
There was a louder tapping than normal when I moved the car,and with my stethoscope, I could clearly detect the noise around No4!
I now have a choice to make.
Investigate again!
Take the head off,and get it checked.
Just bung the spare one on after looking at the liner closer.
Or.!!
Save doing all that stripdown and reassembly again and,for the sake of £25,try some of the sealant.
If it doesnt work,dont mess about just swap engines.
Or just get on with it and swap engines?
Any further work on the rover is now suspended till I decide on a plan what to do.
Problem being the MG is on the ramp and the engine hoist is above it,and cant leave the MG,or TR6 out overnight!
There was a louder tapping than normal when I moved the car,and with my stethoscope, I could clearly detect the noise around No4!
I now have a choice to make.
Investigate again!
Take the head off,and get it checked.
Just bung the spare one on after looking at the liner closer.
Or.!!
Save doing all that stripdown and reassembly again and,for the sake of £25,try some of the sealant.
If it doesnt work,dont mess about just swap engines.
Or just get on with it and swap engines?
Any further work on the rover is now suspended till I decide on a plan what to do.
Problem being the MG is on the ramp and the engine hoist is above it,and cant leave the MG,or TR6 out overnight!
If the camshaft in your current engine is in need of replacement, which by the sound of it, it is, then ideally that should be replaced also along with 16 new lifters. So if you decide to do that then the best option by far is just to remove the engine and put in your replacement. Is your spare fully reconditioned?
That way you'll alleviate the problem of having to remove and refit cylinder heads on your existing engine, which you may then have to remove anyway. Given that the engine is tapping loudly that does indeed suggest a liner problem.
Ron.
That way you'll alleviate the problem of having to remove and refit cylinder heads on your existing engine, which you may then have to remove anyway. Given that the engine is tapping loudly that does indeed suggest a liner problem.
Ron.
Pilkie
Active Member
If it was,I wouldnt think twice about it!SydneyRoverP6B said:
Its a good running engine,at least it started and ran without problems of noise or signs of overheating,from a 65000mile 1971 car I broke,there was an issue with the gearbox and terminal rust.
Gearbox issue was the BW35 selector rod link was broke off,and that box is now in my car when my BW65 went bang!.
Am going to buy a tin of sealant,and give it a go,and hope it gives me enough time to clean and prep the spare engine,and get the MG back to roll in/out of garage state.
Hi Dave
Well, I've never heard of a moved or cracked liner on a 3.5. There's always a first of course, but I'd be astounded if it only leaked into the cylinder, much more likely to leak into the sump. Which leaves cracked head. How would a moved liner leak into the cylinder anyway?
Do you know what the state of the cam in your spare engine is? You'd need to have a look to really tell, which at least means inlet manifold off.
I think I'd try that bottle of gunge in an effort to put off the evil day to a more convenient time.
Chris
Well, I've never heard of a moved or cracked liner on a 3.5. There's always a first of course, but I'd be astounded if it only leaked into the cylinder, much more likely to leak into the sump. Which leaves cracked head. How would a moved liner leak into the cylinder anyway?
Do you know what the state of the cam in your spare engine is? You'd need to have a look to really tell, which at least means inlet manifold off.
I think I'd try that bottle of gunge in an effort to put off the evil day to a more convenient time.
Chris
Pilkie
Active Member
Hi Chris.
Liner isnt cracked,its the block around it,allowing it to move up and down a very minor amount,tapping on the head.
Water seeps up the side and into the cylinder,as the bottom is sealed,and cant get into the sump,after the engine has forced combustion pressure via the same route into the cooling system.
Gives the same rank smell of headgasket failure in the water!
When its left standing you get seepage into the bore and it evaporates as its steaming hot,thus water loss without any definate trace,which is what ive had for a while anyway,thinking it was a slight head leak!.
Have a read of this!
http://www.v8engines.com/Acrobat/LRO_May_small.PDF
Liner isnt cracked,its the block around it,allowing it to move up and down a very minor amount,tapping on the head.
Water seeps up the side and into the cylinder,as the bottom is sealed,and cant get into the sump,after the engine has forced combustion pressure via the same route into the cooling system.
Gives the same rank smell of headgasket failure in the water!
When its left standing you get seepage into the bore and it evaporates as its steaming hot,thus water loss without any definate trace,which is what ive had for a while anyway,thinking it was a slight head leak!.
Have a read of this!
http://www.v8engines.com/Acrobat/LRO_May_small.PDF