Possible head gasket - arrrgh

AussieMozzie

AussieMozzie

Member
Tadpole
Joined
Oct 24, 2021
Messages
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Location
Adelaide
As a few of you have no doubt seen, I have been having some fun getting my 407 Coupe 2.7lt hdi back on the road. The most recent issue once i had it back on the road was the car Surging, lack of power, and then stalling. I pulled over, popped the bonnet and...

1. Coolant was everywhere - I tracked this back to one of the expansion tank return hoses, the connecter had cracked and it wasnt holding pressure - coolant had sprayed out of this everywhere
2. Before I did this work, I had some minor surging in traffic - it was one of the things I was hoping would be fixed. This started happening after I replaced the glowplugs - and based on the below I am leaning towards it being an early indicator of head gasket issue
3. I got the car towed home, made a repair to the connector, and flushed the coolant system, bleeding the air out. What i noticed
a. Car starts and idles with no problems.
b. Once the revs get above about 1200 - 1500 rpm - there is a big bubble of air in the expansion tank followed by lots of little bubbles (lemonade) - and she stalls.
c. Got error codes P0104, P0299, P2279.

This is screaming head gasket in my mind - and now I need to decide what to do. I dont know much about these motors, and whether replacing a head gasket is worthwhile - i do know i have already bled some thousands into fixing various issues already - mainly on parts and tools.

So I am looking for some advice. I am thinking
1. Head gasket is likely not leaking much at idle, but is substantially when the turbo kicks in. This is the bubbling in the coolant expansion tank - and the stalling is probably the ECU having a fit over lost boost pressure and or incorrect air fuel mixture. I expect this is also the origin of code P2279 - indicating loss of boost after turbocharger.
2. Tempted to try some of the Nulon head gasket fix stuff. If it is mainly an issue under boost - then my simple mind wonders if it is a fairly small hole/s in the head gasket
3. Possibility of other damage - I don't know how robust these engines are. If I get this fixed, I need to work out whether I pull the heads myself and send them off to a head reco place, pull the engine and get it reconditioned, get a mechanic to do the work, or wreck the car and get another one.

All and any advice is welcome :)
 
I'm certainly no expert but it sounds like your investment may be best served by getting the head off and inspecting it to determine whether a new gasket will suffice. If not, it's already off for machining or replacement.
 
Yep.....I know even less than both of you put together but the advice given by The Gonz makes perfect sense to me BECAUSE: #1 If it is the head gasket etc you are already half way there when it come off..... #2 You are in a much better position to inspect it VERY CLOSELY instead of prognosticating and....#3 If it is the head and associated bits and you don't feel comfortable with your abilities (like me) it's out and you can dump it on the counter of someone who can fix it for you. WIN WIN all round I would think.🤗
As I said.."Makes perfect sense! But what would I know? 🔧🔩⚙️🛠
 
FWIW, i would be trying the easy fix with a chemical leak fix, to see what else has happened. It just may be all that it needs, to get it going for a while and then you can evaluate what you want to do next. Good luck. I am about to go through the get back on the road journey, myself. Enjoy!
 
Try some chemiweld or bars leak, or even the Gold flakey head gasket stuff, even though it might throw codes.

Are you bleeding it before or after the thermostat has opened?

I'd be going back to basics
You've had it hot once, that once is enough for the thermostat to not work again.

When you've got it at 1,500 rpm is it blowing water out the exhaust??? That's where it's going to go.

Don't rip the head off unless your 100% Checked everything, and it's thousands and thousands to to do those 2.7 hdi v6 td

Cheers BP
 
Bush Mechanic Have you forgotten about the Egg fix, Emu is better than Chicken :)
Crack it in and away you go :)

OR this stuff Fibreloc
 
Thanks all for the replies. Based on what I am seeing, I am

1. Trying the Nulon head gasket fix stuff. I believe this is the gold flakey stuff that BP505 is referencing - it certainly looks gold and flakey. Similar to the fibrelock and chemiweld etc. I have put this in, waiting for it to cool down now
2. Compression / Leakdown, and coolant system pressure test. Hmmm, I was looking these up, and wondering whether I get a garage to do them, or get the tools and do the tests myself. From what I understand

a. Coolant pressure test will allow me to work out if
i. Coolant system is holding pressure; if not
ii. Should be able to see where the pressure is escaping if through a hose / expansion tank etc (unless it is radiator cap)
iii. If it is head gasket - and their is a coolant leak into one or more cylinders, If I remove the glow plugs I should be able to see it weep out (or put a tissue in the hole, and look for it to "blow out" when i put some pressure in the coolant system

b. Compression test will enable me to easily and quickly see which cylinders are not holding compression.

c. Leakdown test should allow me to identify where the compression leak is happening. Whether it is coolant (Head gasket), Oil manifold (probable piston rings), Intake or exhaust (valve, or stem seal or other head issue)

I don't have a source of shop air at the moment - so depending on how the Nulon stuff works - I could get a cheap set of tools for Coolant pressure and Compression test - and once / if I have identified an issue then outsource the leakdown test on the affected cylinders to a local garage / mechanic - or see if Lube mobile or someone can come out and do it for me.
 
Yes that's the stuff but beware the flakes block sensors and throw codes, and is a temporary fix, eventually you'll have to fix it properly.

Is it blowing steam out the exhaust? If it is that stuff won't fix

Like we've all said go back to basics,

Cheers Bp
 
BP505v6Turbo said:
Try some chemiweld or bars leak, or even the Gold flakey head gasket stuff, even though it might throw codes.

Are you bleeding it before or after the thermostat has opened?

I'd be going back to basics
You've had it hot once, that once is enough for the thermostat to not work again.

When you've got it at 1,500 rpm is it blowing water out the exhaust??? That's where it's going to go.

Don't rip the head off unless your 100% Checked everything, and it's thousands and thousands to to do those 2.7 hdi v6 td

Cheers BP
Click to expand...
BP505v6Turbo said:
beware the flakes block sensors and throw codes, and is a temporary fix, eventually you'll have to fix it properly.

Is it blowing steam out the exhaust? If it is that stuff won't fix
Click to expand...

Thanks Bp.

I did not see any steam out the exhaust, from what I can see it is not using coolant, but it is undrivable at the moment - every time it gets up to 1500 RPM or so it stalls, or rather the engine retarts somewhat, and stalls a second or so later. This is bad in its own way

A few more things based on your comments
1. I think the thermostat is opening - at least the car is not overheating at idle. From my knowledge these are meant to open at 88 degrees celcius. When I get it up to that temp again I will be able to tell. Yesterday I got it close, and I noticed the coolant temperature suddenly drop a few degrees, and the coolant in the expansion tank "agitate". Pretty sure that was the thermostat opening, but will keep an eye on it
2. I have been bleeding it before the thermostat opened. As I understood it the process is to do it by gravity
a. open bleed valves
b. Put the filling cylinder on the expansion tank, and half fill it (we want the coolant in here to be the highest point)
c. start the car - idle, watch bleed valves, and close when they stop blowing bubbles
d. Celebrate

Please tell me if I am missing something here.

Also, some information from today - in order to get the Nulon in I had to take off the top radiator hose, the one that connects to the Thermostat. I noticed after putting it back on, it did not get hard (and i did try squeezing it for a while - this blew bubbles with each squeeze into the expansion tank)- my presumption is that this hose will not bleed until the thermostat opens. I was also concerned that maybe it was continuously filling with exhaust gas. Time will tell I suppose
 
Its really not playing fair is it?
As suggested by others, pressure check the cooling system and a cylinder compression test seem like the best way to find out what is going on.
Additives are likely only a temporary solution, if any. Mostly used for small, pin prick holes, in my experience. If others have had better outcomes please let us know what brand worked best.
Keep us updated
Good luck.
 
I highly recommend you avoid putting any additive in your engine cooling system for temporary coolant/head gasket leak fix. They tend to damage any sensor attached or works with the coolant, like the Coolant level sensor and CTS. In one case, it blocked the radiator with some formation that owner had to replace the radiator.

If you have done the diagnosis and ruled out every other cooling system component aside the head gasket, you can always as remove the cylinder head and fix the issue once and for all. Not every car fix is DIY. Let a technician/mechanic handle the job for you.

V6s are meant to be pushed hard and you are comfortable with managing the issue with chemical temporary fix?

Lion-King Monk.
 
i have had experience over the years with thermostats and have found that there operation in modern cars is somewhat different to the good old days ,its not just an open and shut case ,in my 405 MI 16 and my sons 3 series B M W had the thermostat starts off cold by circulating coolant through the heater rad [ to de ice the windscreen and worm up the interior of the car ] then when wormed up shuts off that passage and connect engine to main radiator ,somehow coolant still finds its way through the heater some other way ,,could it be that your thermostat is not doing the complete change over ,getting stuck halfway through its operation ,is it at all possible to take it out and check its operation, in boiling water ,i tried removing the thermostat from my son beemer so he could drive it ,it made the symptoms worse ,there must be someone on here that has specifics on this engine ,above all make sure you are making your decisions based on facts, rather than assumptions ,check the simple things first ,maybe the t/ stat or housing is a mission to get out on a v6 i dont know
 
AussieMozzie said:
Thanks Bp.

I did not see any steam out the exhaust, from what I can see it is not using coolant, but it is undrivable at the moment - every time it gets up to 1500 RPM or so it stalls, or rather the engine retarts somewhat, and stalls a second or so later. This is bad in its own way

A few more things based on your comments
1. I think the thermostat is opening - at least the car is not overheating at idle. From my knowledge these are meant to open at 88 degrees celcius. When I get it up to that temp again I will be able to tell. Yesterday I got it close, and I noticed the coolant temperature suddenly drop a few degrees, and the coolant in the expansion tank "agitate". Pretty sure that was the thermostat opening, but will keep an eye on it
2. I have been bleeding it before the thermostat opened. As I understood it the process is to do it by gravity
a. open bleed valves
b. Put the filling cylinder on the expansion tank, and half fill it (we want the coolant in here to be the highest point)
c. start the car - idle, watch bleed valves, and close when they stop blowing bubbles
d. Celebrate

Please tell me if I am missing something here.

Also, some information from today - in order to get the Nulon in I had to take off the top radiator hose, the one that connects to the Thermostat. I noticed after putting it back on, it did not get hard (and i did try squeezing it for a while - this blew bubbles with each squeeze into the expansion tank)- my presumption is that this hose will not bleed until the thermostat opens. I was also concerned that maybe it was continuously filling with exhaust gas. Time will tell I suppose
Click to expand...
Aussiemozzie can I ask,
Are you bleeding it with the heater tap on hot? This is always a mistake made.
 
Ikenna351 said:
V6s are meant to be pushed hard and you are comfortable with managing the issue with chemical temporary fix?

Lion-King Monk.
Click to expand...
I am very aware this would be temporary - thanks for the warning. It doesnt look like it worked anyway - but will fire it up again tonight / tomorrow and see. It would only be to give me a month or two of respite so I could get all my ducks in a row to fix properly
 
BP505v6Turbo said:
Aussiemozzie can I ask,
Are you bleeding it with the heater tap on hot? This is always a mistake made.
Click to expand...
hmmm. Good question. Initially no, but after the Nulon stuff yes. From what I have subsequently learned the only reason they say to turn on the heater is to stop the car from overheating - and I do not appear to be having that issue. Will bleed again tonight, and make sure heat is off.
Otherwise - is the technique I wrote down what should be done ? I did get it out of servicebox... and there was a whole lot in there about revving at 2300 rpm until the fans kicked in etc - but that looked like it was for when doing a vacuum fill - not a gravity fill.
 
pugwash said:
i have had experience over the years with thermostats and have found that there operation in modern cars is somewhat different to the good old days ,its not just an open and shut case ,in my 405 MI 16 and my sons 3 series B M W had the thermostat starts off cold by circulating coolant through the heater rad [ to de ice the windscreen and worm up the interior of the car ] then when wormed up shuts off that passage and connect engine to main radiator ,somehow coolant still finds its way through the heater some other way ,,could it be that your thermostat is not doing the complete change over ,getting stuck halfway through its operation ,is it at all possible to take it out and check its operation, in boiling water ,i tried removing the thermostat from my son beemer so he could drive it ,it made the symptoms worse ,there must be someone on here that has specifics on this engine ,above all make sure you are making your decisions based on facts, rather than assumptions ,check the simple things first ,maybe the t/ stat or housing is a mission to get out on a v6 i dont know
Click to expand...
Yeah - it looks like a lot of coolant pathways through EGR valves etc. However, the thermostat hose goes straight to the top of the radiator - if I had to guess based on the diagram and I what i think i know i would say
1. Coolant heats up in the engine, and circulates through the EGR valves, and auto trans heat exchanger in order to bring the whole system up to temperature faster
2. When the system comes up to temp (which can take a while due to 1.) - then the thermostat opens, and circulates the coolant from the radiator.

This is very simplistic - there are likely many little steps i am missing - but the upshot of that is i would expect engine coolant to circulate while warming up, but radiator coolant to only flow in volume once the thermostat has opened

I can get the thermostat out without too much effort - but pretty sure I would need to yank the butterfly housing to do so. It was a brand new thermostat I put in there. I havent "boiled" a thermostat to see if it worked since I had my charger when I was a much younger lad - might have to hunt around and see if I have a kitchen thermometer to check that
 
AussieMozzie said:
hmmm. Good question. Initially no, but after the Nulon stuff yes. From what I have subsequently learned the only reason they say to turn on the heater is to stop the car from overheating - and I do not appear to be having that issue. Will bleed again tonight, and make sure heat is off.
Otherwise - is the technique I wrote down what should be done ? I did get it out of servicebox... and there was a whole lot in there about revving at 2300 rpm until the fans kicked in etc - but that looked like it was for when doing a vacuum fill - not a gravity fill.
Click to expand...
Peugeot 407s don't have heater taps they have full flow heater
 
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