Oh no! poss HGF advice please!
Discussion
following on from my other thread on my p6 3500 s i found that the vacu adv on the dizzy wasnt working properly and now its fixed it really does go much better. no misfires and a lot more oomph. still not perfect but i was happy.
until
driving to work - i only live 3 miles away i parked up and saw a trail of water behind the car and out the carpark. no probs i thought and topped it up. ill keep an eye on it.
next day i drove home and pulled up. i was greeted with a pssssscchhhhhhh as a litre of water bubbled down the overflow by the rad cap and onto the road. somewhat perturbed i thought an iffy stat might be the issue and changed this.
next day - all was fine.
today though its done it again and this isnt looking good. all i can think is that the coolant sys is pressurising with gases and blowing water out the rad cap. i now have evidence that this happens on the move, though especially at rest. please tell me i dont need a pair of head gaskets!
until
driving to work - i only live 3 miles away i parked up and saw a trail of water behind the car and out the carpark. no probs i thought and topped it up. ill keep an eye on it.
next day i drove home and pulled up. i was greeted with a pssssscchhhhhhh as a litre of water bubbled down the overflow by the rad cap and onto the road. somewhat perturbed i thought an iffy stat might be the issue and changed this.
next day - all was fine.
today though its done it again and this isnt looking good. all i can think is that the coolant sys is pressurising with gases and blowing water out the rad cap. i now have evidence that this happens on the move, though especially at rest. please tell me i dont need a pair of head gaskets!
I'd have thought it is very unlikely, but the easy way to check is to get a garage to do a chemical test on the coolant that will detect dissolved exhaust gases. Last time I had one done (admittedly a few years ago) the cost was £10, and it would conclusively rule out the head gasket. Frost Auto Restoration sell a DIY kit to allow you to do this yourself, but it's about £35 IIRC.
I've heard that some garages use MOT emissions probes to 'sniff' for exhaust gas in the cooling system, but I've never tried this myself.
I've heard that some garages use MOT emissions probes to 'sniff' for exhaust gas in the cooling system, but I've never tried this myself.
shouldbworking said:
Could still be something simple like the radiator cap.
Indeed. Or a failed thermostat, or a localised airlock in the cooling system.For the cost of a new rad cap, thermostat & gasket (probably not even the thick end of a tenner), I'd change those and bleed the cooling system thoroughly before I started worrying about head gaskets.
What's the temperature gauge doing whilst the cooling system is blowing all this water out?
For what it's worth, if it does turn out to be the head gasket, there's no real reason to change both on a V8 engine if only one of them is blowing. If you can find out which one it is (by means of a compression test), you can just change it on that side.
Sam_68 said:
shouldbworking said:
Could still be something simple like the radiator cap.
Indeed. Or a failed thermostat, or a localised airlock in the cooling system.For the cost of a new rad cap, thermostat & gasket (probably not even the thick end of a tenner), I'd change those and bleed the cooling system thoroughly before I started worrying about head gaskets.
What's the temperature gauge doing whilst the cooling system is blowing all this water out?
For what it's worth, if it does turn out to be the head gasket, there's no real reason to change both on a V8 engine if only one of them is blowing. If you can find out which one it is (by means of a compression test), you can just change it on that side.
Paolo, I take it that you resolved this?
I'd had similar problems on a P5B and it was indeed HGF
See my thread here: http://www.pistonheads.com/gassing/topic.asp?h=0&a... with lots of piccies!
I'd had similar problems on a P5B and it was indeed HGF
See my thread here: http://www.pistonheads.com/gassing/topic.asp?h=0&a... with lots of piccies!
Certainly get a pressure test to see if it's a HGF. The P6 cooling system is pressurised and the rad caps are known to wear and blow! The rating should be on the cap.
I've heard lots of stories about incontinent P6's blowing water, most of the time it's either a sludged up rad and blocked water passages. If the water pump is making a racket, there's your clue.
Most owners do what's known as a reverse flush. Do the rad disconnected from the engine using a moderate pressure hose, get this along the bottom of the rad to get the crud out via the top hose outlet.
Next, with the rad disconnected, get the airbox off and get the inlet manifold hose off the manifold, using a garden hose mated to the bottom rad hose, flush the engine so the water comes out of the inlet manifold, flush until it is totally clear.
Next the heater box, using the manifold pipe to the heater, disconnect the inlet pipe to the heater box and do the same again.
Some owners also swear by a de-furring of the heater box, this must be done with the heater TOTALLY disconnected from the engine. Cork one hose up and using a warm water solution poured in to the other hose, defur the box. Flush well.
After all that, mix up a 40% antifreeze solution and it should be fine.
Personally, I flush mine every year through the bottom rad hose and running a hose through the inlet manifold. Then I fill the engine using the manifold hose to the heater box with the rad cap off and the inlet manifold intake corked up.
This prevents heater box vacuum lock which happens all too often, also, this runs new antifreeze through the heater box, engine and then rad.
Once this is done, start the engine from cold, start the heater box and the rad is topped up before putting the rad cap back on as it is a pressured system.
I've heard lots of stories about incontinent P6's blowing water, most of the time it's either a sludged up rad and blocked water passages. If the water pump is making a racket, there's your clue.
Most owners do what's known as a reverse flush. Do the rad disconnected from the engine using a moderate pressure hose, get this along the bottom of the rad to get the crud out via the top hose outlet.
Next, with the rad disconnected, get the airbox off and get the inlet manifold hose off the manifold, using a garden hose mated to the bottom rad hose, flush the engine so the water comes out of the inlet manifold, flush until it is totally clear.
Next the heater box, using the manifold pipe to the heater, disconnect the inlet pipe to the heater box and do the same again.
Some owners also swear by a de-furring of the heater box, this must be done with the heater TOTALLY disconnected from the engine. Cork one hose up and using a warm water solution poured in to the other hose, defur the box. Flush well.
After all that, mix up a 40% antifreeze solution and it should be fine.
Personally, I flush mine every year through the bottom rad hose and running a hose through the inlet manifold. Then I fill the engine using the manifold hose to the heater box with the rad cap off and the inlet manifold intake corked up.
This prevents heater box vacuum lock which happens all too often, also, this runs new antifreeze through the heater box, engine and then rad.
Once this is done, start the engine from cold, start the heater box and the rad is topped up before putting the rad cap back on as it is a pressured system.
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