Oh b*lls what now?!!
Discussion
Just driving into Manchester today and the engine on the 400 decides to stop whilst doing about 60 on the motorway.
"This is getting a bit too common" thinks I. Since it has done the exact same thing twice in the last couple of weeks.
I pull in on the hard shoulder and turn it over - it doesn't want to know. But past experience tells me that in about 5-10 minutes I'll start, and sure enough it does.
Whilst waiting I pull off one of the plug leads and try a spare spark plug against the engine. It sparks, Hmmm.
Anyway, sure enough after about 10 mins it starts so off I go - for about a mile
and it stops again. 
Well after about four miles and the forth time of it happening I decide to call out the RAC.
This time it takes ages before it will start again (well I had nothing else to do whilst I was waiting!)and I notice that after the engine has been running for about 5 mins, that water is bubbling out of the cap on the expansion tank, even though the temperature guage hasn't even made it to ninety yet.
Now these could be two unrelated symptoms but I've got a baaaad feeling that I could be looking at a cylinder head problem.
"This is getting a bit too common" thinks I. Since it has done the exact same thing twice in the last couple of weeks.
I pull in on the hard shoulder and turn it over - it doesn't want to know. But past experience tells me that in about 5-10 minutes I'll start, and sure enough it does.
Whilst waiting I pull off one of the plug leads and try a spare spark plug against the engine. It sparks, Hmmm.
Anyway, sure enough after about 10 mins it starts so off I go - for about a mile
and it stops again. Well after about four miles and the forth time of it happening I decide to call out the RAC.
This time it takes ages before it will start again (well I had nothing else to do whilst I was waiting!)and I notice that after the engine has been running for about 5 mins, that water is bubbling out of the cap on the expansion tank, even though the temperature guage hasn't even made it to ninety yet.
Now these could be two unrelated symptoms but I've got a baaaad feeling that I could be looking at a cylinder head problem.
And before anyone asks:
The temperature guage has been checked recently and been shown to read accurately.
The filler cap on is the correct rating (according to the bible) and is only a couple of months old.
Also the radiator, hoses, plugs & leads have all been replaced withing the last few months.
Anybody care to offer any opinions before it goes to the garage tomorrow? I've got a feeling this one's gonna sting
Would that be small frothy white bubbles? cos mine did that the other week when the hose split and i had to to fill it with coolant. And to top it all, today i found a small crack in the middle of the vee just forward of the bell housing, which small drops of oil would ooze out under acceleration. Doesn't sound good eh!!
Have to say it does sound like a head/head gasket problem. Even more likely if it continues to chuck coolant out immediately after the engine is switched off. Why dont you whip the heads off and have a look (a Haynes Rover V8 manual is much cheaper than a garage) - its not a huge job and it might only be a gasket gone. Unlikely to be a cracked head if its been running well for a while and has not had any undue provocation such as overheating.
Not quite sure why this would stop the engine during normal running though, even a severe leak would not normally stop it completely. (I managed to limp off the motorway on 4 cylinders in a 350 a few years ago and it kept running). You may as you say have another problem causing that. Some sort of electrical connection breaking down when it gets hot perhaps? possibly leading to a fuel starvation or ignition problem??? Probably best to get the heads checked out first though.
Good Luck!
Not quite sure why this would stop the engine during normal running though, even a severe leak would not normally stop it completely. (I managed to limp off the motorway on 4 cylinders in a 350 a few years ago and it kept running). You may as you say have another problem causing that. Some sort of electrical connection breaking down when it gets hot perhaps? possibly leading to a fuel starvation or ignition problem??? Probably best to get the heads checked out first though.
Good Luck!
Don't worry about it Dicky! (pinching the thread that is, you should probably worry about the engine 
)
I've got to agree with you Brm that I can't see how one cylinder - even if it was full of coolant - would stop the engine running.
When it did stop, the engine smelled a bit "gassy" to me which first made me wonder about over-fueling problems, but it doesn't run rough first, it just stops (maybe ignition module?).
I can't help thinking I'd be better off with a good old bank of carbs instead of all this electronic wizardry!
But what I really need it good ol' Steve Heath to come online and tell me theres a screw located in the bottom of the boot which I just have to rotate half a turn and It'll all be fine!
Where are you when I need ya Steve?!
) I've got to agree with you Brm that I can't see how one cylinder - even if it was full of coolant - would stop the engine running.
When it did stop, the engine smelled a bit "gassy" to me which first made me wonder about over-fueling problems, but it doesn't run rough first, it just stops (maybe ignition module?).
I can't help thinking I'd be better off with a good old bank of carbs instead of all this electronic wizardry!
But what I really need it good ol' Steve Heath to come online and tell me theres a screw located in the bottom of the boot which I just have to rotate half a turn and It'll all be fine!
Where are you when I need ya Steve?!
Sounds like a head gasket or similar problem. I wouldn't drive the car but get it to hospital and it might just be a gasket and you might have saved the heads from warping. When they strip the car chcek the cams etc just in case they need replacing.
Easiest way to see if it is a gasket is to do a cooklent chmical test. Lot quicker and easier than whipping the heads off which is pretty specialised work. Lots of things to get wrong.
Steve
Easiest way to see if it is a gasket is to do a cooklent chmical test. Lot quicker and easier than whipping the heads off which is pretty specialised work. Lots of things to get wrong.
Steve
Bobfrance,
So many things to go wrong, but don't rule out some kind of electrical failure. When the engine dies, does it splutter or does it just cut out? I ask because I had a problem with my immobiliser circuit last year - the relays were failing under load (once they were hot) and the engine was just cutting out at the strangest of times. Change of immobilizer; problem solved.
Regards
So many things to go wrong, but don't rule out some kind of electrical failure. When the engine dies, does it splutter or does it just cut out? I ask because I had a problem with my immobiliser circuit last year - the relays were failing under load (once they were hot) and the engine was just cutting out at the strangest of times. Change of immobilizer; problem solved.
Regards
I know it sounds to good to be true ,you say the car was ticking over when it overheated have you checked the electric fan is working .When i had my 350 the mot testing station left it ticking over and the water came gushing out of the expansion tank!,anway it turned out that the fan was siezed solid!{they dont seem to get used much}as for cutting out it could be fuel pump on its way out {they tend to come back to life when they been left to cool down}or even bad Electrics
Yes but you cant really go off the gauge i dont think they are that acurate!and the sender could be faulty anyway{had to buy a new one for mine} , if it is standing still with engine runnig it should in theory be moveing up and down as the thermostate opens/closes i also remember c/neil telling me that there were 2 types of sender fitted you had to have the one that matches the gauge
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