[m-power_tuning]

Hi I wonder if anyone can help with my problem.
I have a 2006 335d which happens to be drinking coolant like no tomorrow.
I can drive the car about 5-10 mins before the "coolant too low" message appears on the idrive and the fans activate on full power.
I have checked the usual in regards to head gasket symptoms and there seems to be the same level of oil in the engine and no contamination in the coolant tank or in the engine oil. If I let the car sit for a day or so I see white smoke from the exhaust (also suggesting head gasket failure) and I can feel a loss of power and a judder during acceleration.
The only thing I have changed since this started was an EGR thermostat which had a leaky o ring. I bought a new stat but it didn't come with a new o ring so I fixed this by using some loctite gasket glue which seems to have worked.
I have taken it to a garage who had no luck in finding any leaks so I'm a bit stumped atm.
Anyone else experienced this mysterious vanishing of coolant? Any help or suggestions will be much appreciated.

[CustomColours]

Maybe a compression and leak down test is worth a try. Its the easiest way to find out if you have a head gasket issue. Whikst there pressurize the coolant system using a presaure tester, watch the guage and look for a loss of pressure. If there is one then you may be able to hunt down a leak thats not noticed after driving once the coolant pressure drops etc.

[m-power_tuning]

Thanks for the suggestion. Im going to get the car booked in for diagnosis tomorrow at a bmw specialist so I will see what comes out of this.

I'll come back with an update

[m-power_tuning]

update:

i have booked the car in for diagnostics on monday

i had a friend use INPA diagnostics on the car and it came up with 9 errors

6x glow plug error
smooth running control
particle filter
fuel filter

also noticed today there is coolant mixing with oil in the engine as the oil cap has a grey mustard type of goo on it.

will it throw out an engine over heat error on the dash if there isn't any coolant in the system to get the engine temperature from?

car has never over heated as far as im aware as there have been no over heating errors show up on the dash except the coolant too low error. it only has 76000 on the clock so can head gasket fail this early?

any ideas guys?

thanks

[tennis_pr0]

Sounds like gasket leak. Compression and then leak down test...

[335DEE]

check your EGR cooler, you need to remove it to check , if the inside of the cooler looks clean ( as opposed to black soot) then the cooler is passing water into the charged air line.

If you EGR is functioning then there is a small chance that some of this coolant has made its way into the inlet manifold and into the piston which may have caused the head to crack under compression

[m-power_tuning]

Update
I've been around to 7 different garages and no 1 can do a leak down test as they don't have the tools. I went to one guy who was adamant it isn't head gasket as he was saying there should be a pressure build up in the coolant tank and pipes. He also said the mayo like substance on the oil cap could be from using the car on short journeys which may be true as I have only been moving the car around to garages lately. Can anyone confirm.

Also realised climate control doesn't seem to give out hot air always. Seems to produce hot air for a while then it goes cold for a while. Could this be linked?

There's 2 egr which should I be looking at high pressure egr or low pressure?

thanks in advance

[335DEE]

whereabouts in UK are , I have a guy with a proper kit.

The EGR cooler is the thing that you stuck your thermostat into with no seal

[Russbmw]

Yes, a light layer of mayo goo on the oil filler cap when the car hasn't been driven long enough to heat up properly and burn off any condensation has been a BMW engine trait for years now.

Maybe i'm missing something, and I can't confess to knowing the 335d engine at all, but if the car's not loosing coolant, there's no contamination of oil or water, and the only thing you've done is bodge the thermostat, which has now given you heating that's blowing hot and cold (ignoring the white smoke as that, along with the oil cap mayo, is likely to be attributed to not driving the car anywhere near long enough to let things heat up and any moisture accumulated in the exhaust evaporate) - the thing that instantly springs to mind is simply that the cooling system has an air lock or air leak from the thermostat.

Have you physically checked the coolant level, and if so, what kind of quantity are you needing to top it up with on each time? In my experience, the drop in level required to trigger the low coolant level warning in most BMW's (historically) is probably not much more than a decent mugfull - so what the warning light may be insinuating is a huge loss, is actually not a lot - and something that could easily be caused by big burps of trapped air escaping, causing the level to drop.

If you're headgasket is gone, and you were burning that much coolant, the car would barely run - and (as has been suggested) the cooling system would most likely be being pressurised as a result.

[m-power_tuning]

thats great much appreciated ill take a look at this tommorow.

im in manchester

[335DEE]

if your car had headgasket issues then the thing would be running like a proper bag of crap. If you took the coolant cap off while the car was running it would be gushing water out as diesels operate massive compression.

If the car is idling nice and smooth but you are seeing white smoke then i'd be 95% certain your EGR cooler is cracked.

I've been through this myself , took a long while to diagnose .. thought the engine was trashed , injectors were knackered .. the full works. Video of what I had is below

[m-power_tuning]

reply to russbmw the car is loosing a lot of coolant i tend to lose all of it from the expansion tank when i drive the car hard for about 10 - 15 mins but doesn't seem to lose as much if driven like an oap.

the video is exactly my symptoms but not to that extreme. did it always used to smoke or clear up once the car is warmed up? mine clears up after car warms up. also when i rev the car hard on stand still coolant is thrown out of the exhaust and onto the floor by the exhausts.

one other thing is it ok to top the coolant up with tap water for now as coolant is becoming expensive.

appreciate all the help guys

[Russbmw]

If its loosing that much, then its definitely not the head gasket.

If it were my car, I'd have the cooling system pressure tested. Could be a split hose like I had on my e39, where there was no sign of a leak as the hose with the split would only open when the car warmed up, proceeding to squirt coolant directly onto the engine block, where it would evaporate without trace!

That would do the same, loose a shitload of coolant in a short space of time and the coolant warning light would come on.

I was assume a pressure test would also indicate if water was doing something with the egr...but I'm not clued up on diesels so much.

Tbh I'm a little suspect of the thermostat fitted without proper gasket.

[335DEE]

ok so whats happening here is that when your car warms up the coolant system pressurises ( its about 1 - 1.5 bar or 15-22 psi) at normal operating temperature.

When you are driving the boost pressure (varying up to 23 psi ) almost equalises with the coolant pressure so you might get a small amount of coolant leaking into the EGR or on the flipside a bit of air getting into the coolant. This is why you don't see any smoke when you are driving.
When you turn the car off what you have is coolant pressure that is still at about 1-1.5 bar, this is where the coolant seeps in while the engine cools down over a few hours, so when you come to it 1st thing in the morning or after a couple of hours it chucks out big plumes of smoke.
The angle of the cooler on the engine dictates that any water will make its way directly into the exhaust which is a good thing because you really don't want it going the other way through the manifold and into the engine !

I wouldn't really use ordinary tap water , it scales up and also is actually corrosive albeit mildly. Probably ok watering the pink stuff a bit but if you are losing that much water i'd look to get it sorted ASAP.

A word to the wiser , these EGR coolers are around £500 from BMW but it is the same part they used on the E46 320d ! so you can source them for about £50 from a scrapper!.

As suggested before , you need to take the cooler off to check .. if the cores inside where the gasses pass are clean then it's a duffer. They should be heavily sooted up.

[Russbmw]

Well, I for one feel enlightened! Thanks Dee!

[335DEE]

Originally Posted by Russbmw

Well, I for one feel enlightened! Thanks Dee!

My car eats these flipping things for breakfast.. Its a well trodden path for me

[m-power_tuning]

I owe u a beer dee. Turned out to be the egr cooler. Replaced it and cars running perfectly

Thanks guys

[335DEE]

No problem, glad to have helped! Is your EGR disabled by any chance?

[m-power_tuning]

U mean the DPF cut off?

[335DEE]

Disabled via a map

[m-power_tuning]

Nope the car is standard unless the last owner messed about with it I wouldn't know

[bmwdiesel]

so i guess my head gasket is blown. today loss of coolant message appeared and when i opened it there was a bit of coolant at the bottom of the tank. when i put the finger in it, it felt oily.....does the oil confirm the head gasket.
reading this it seems it's also possible to confirm by opening the tank cap while engine running, and when it's gushing the water out, than it's double confirmed, right?