Possible head gasket failure

Alchemist · Post by **Alchemist** » Mon Sep 06, 2021 7:02 pm

So my dad's X5 (used to be mine, the bronze one in my avatar) has developed a few engine issues of late out of nowhere and now it seems it's 'burning' coolant.

It's an early E70 3.0D, done around 100k and engine was running fine, doesn't use any oil or coolant. However it's now blowing white smoke and loosing coolant from the rad. The oil is clean however and not contaminated, nothing in the cam cover or on the dipstick, but the water level is dropping and its blowing gas out the back like a steam train (there also seems to be no oil entering the coolant either).

Prior to this it's had a few issues in the last few weeks:

DPF was measuring high and it broke down. RAC called out and said the EGR was blocked. It sound like they sprayed cleaner into the back pressure valve and he inlet and limped it home, although when home it said DPF failed to regen.

It's since had:
New EGR (made no difference, and the old one was fairly clean -still ran bad unless the vacuum pipe too it was removed)
Cross over valve
Pierburg pressure valve
DPF chemical clean
new glow plugs (prob why the DPF wouldn't regen

Any thoughts? Does the white smoke sound like the head or could this be caused by something/somewhere else water is entering the engine (inlet manifold??)

X5Sport · Post by **X5Sport** » Mon Sep 06, 2021 7:12 pm

If the glowplugs have been changed you would be very wise to get the controller replaced as well. Failed plugs often mean failed controller in short order.

Possibly worth getting a cylinder pressure check done as that will help pinpoint any gas leaks from combustion side to cooling side, and pressurising the coolant circuit to look for leaks the other way.

Is it steam, or smoke? My X6 blew white smoke after the glowplugs we’re changed due to contaminants in the exhaust burning off. I then put it into Sport and gave it a bootful at which point the world behind vanished in a seriously impressive cloud of smoke for a few seconds before clearing again. Sine then it’s been fine. White smoke is also in indication of improper combustion (over-fuelling) with the fuel not burning hot enough. I would expect if it was water then for there to be that much you would be draining coolant pretty quickly.

It could be a pressure cap failure on the expansion tank, or a leak elsewhere - hence getting it pressure tested before starting to look at major engine surgery. These units aren’t known for head gasket issues. I don’t remember ever seeing one reported on the forum.

Alchemist · Post by **Alchemist** » Mon Sep 06, 2021 7:20 pm

Thanks buddy, the glowplug controller wasn't replaced (my dad's garage did the repairs. You're right though, I'd have done the controller at the same time as did on my 330D, and made sense to do them all).

It looks like smoke, the car's done 250 miles with the new plugs in (inc towing a caravan) and the fault developed last night. It's possible the new plugs could have registered the ECU to do a DPF purge (apparently the car had this done manually) causing the fumes?

It seems to point to a head gasket, but that the engine is looked after, oil is clean etc makes we wonder. Pressure test is what's needed.

They're stranded in Derbyshire at the moment, hence need to find a local garage

Alchemist · Post by **Alchemist** » Mon Sep 06, 2021 7:25 pm

Oh, and it's draining coolant a full rad in around 10-15miles driving and the smoke seems to be mainly steam.

Could any of the above issues cause a head gasket to blow? Seems odd if it has after this work was done. Could back pressure from a clogged up DPF or EGR pressurise the head?

X5Sport · Post by **X5Sport** » Mon Sep 06, 2021 8:09 pm

The EGR has a water based cooler radiator. If that’s cracked it could be that is dumping coolant water into the inlet side? With the EGR having been changed it might be a pointer? If it was refitted with any tension on the coolant pipes that could cause an issue too.

A bad DPF would bring a warning light on as the system uses back pressure to determine the ‘state’ of the soot load etc. The EGR takes a feed from the exhaust side and it’s output is into the inlet side so it shouldn’t be able to pressurise the head - and N57 diesels run at 17:1 compression (same with the M57 series).

Alchemist · Post by **Alchemist** » Mon Sep 06, 2021 8:15 pm

thanks for that, I'll have a look on Real OEM. I recall my 3 series had an EGR thermostat (the short black plastic one), but not it's own rad. Do you know where it is?

X5Sport · Post by **X5Sport** » Mon Sep 06, 2021 8:23 pm

They don’t all have one. Hard to tell from the images I found, I think it’s top front of the engine for the 30d (almost the same as the E46) and right side on the 40d about halfway back.

30d …N57

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X5Sport · Post by **X5Sport** » Mon Sep 06, 2021 8:28 pm

Earlier 30d (M57 engine)

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: 0BFE6929-401D-4A7E-B677-48D63CBACF23.jpeg (98.17 KiB) Viewed 10956 times

X5Sport · Post by **X5Sport** » Mon Sep 06, 2021 8:34 pm

I’m always suspicious of new work first before suspecting something more serious like a head gasket. It might still be that but I would personally be looking at what’s just been done first, just in case

Alchemist · Post by **Alchemist** » Mon Sep 06, 2021 10:02 pm

Cheers bud, its an M57, I recognise the EGR thermostat from my 330d (had one blow, and another new one weep with a crimped 0-ring).

He needs to inspect the front end, didn't realised the EGR had a radiator, or how it's water would enter the inlet, but it does seem odd it's been blowing white smoke since they worked on it and the oil neither oil or water are contaminated. Will explore further and report back

Leslie · Post by **Leslie** » Mon Sep 06, 2021 10:06 pm

There was a recall on some models for that egr stainless box cracking , I dunno what was affected though but with the amount of coolant loss it shouldn't be too hard to find, head gasket failure on these engines is thankfully rare

Alchemist · Post by **Alchemist** » Thu Sep 09, 2021 5:47 pm

Have just been looking at Real OEM and am now wondering if it's the EGR cooler or thermostat. Is there a way if this is faulty or not assembled right water can be either pulled into the inlet manifold or it can become pressurised and water pushed into the exhaust? Been a while since i took an EGR thermostat apart (and the car's 300 miles from me) but i recall they're fairly simple inside.

Andrew

Leslie · Post by **Leslie** » Fri Sep 10, 2021 10:40 pm

If the cooler was cracked internally id expect the Egr gas would carry any water leaks straight into the engine resulting in plenty of steam

, the egr thermostat would make no difference broken or not as many are broke and it only makes the engine run too cool .If you take it off and can see through it its broken as it should be closed when cold. Egr thermostat is only about 25 quid don't even waste you time taking it apart change it but it won't fix the steam issue (imo)

Alchemist · Post by **Alchemist** » Mon Sep 13, 2021 10:11 am

Just want to say a MASSIVE thanks to everyone on this thread.

So my dad bypassed the stainless exhaust cooler, and the white smoke stopped. It would have been really hard to diagnose this remotely myself (as he's in Derbyshire on stranded on a caravan site and I'm in Epsom, 250 miles away), especially as the local garage told him it was the head.

Thanks to EVERYONE who's taken the time to comment on this post - genuinely appreciated Thanks to YOU there's now a guy in Derbyshire who can sort his car and get it home - you've saved a lot of stress (and money).

Long term I've said to blank off the gas going into the EGR and code it out, then remove the EGR thermo and cooler altogether.

Leslie · Post by **Leslie** » Mon Sep 13, 2021 12:53 pm

Great news may e the DPF was an early casualty of this problem before it got bad

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