Coolant draining into oil but not milky

[Twowheelsintransit]

I'm completely stumped on this one. I've got a 2015 Peugeot boxer with the 2.2 transit engine.
It's been intermittently burning white smoke on start up, especially in the cold and has been consistently losing some coolant but has now started absolutely chugging it out. I initially suspected the EGR cooler so I've bypassed that, that's had no effect other than firing an engine light and putting me into limp mode on the test drive? Will have to investigate that also...

The strangest thing that I cannot for the life of me figure out is I've realised that the coolant seems to be going into the sump, the oil level rises as the coolant drops and is now significantly above the max fill line. The oil is also very thin. But it is not milky at all. I suspect that my white smoke is the water in the oil burning off during running. But I don't understand from where the coolant could so quickly drop into the oil.

Of course the first thought is a head gasket but the van runs fine and there is no oil getting into the coolant whatsoever ever, I've also done a sniff test which showed no combustion gases in the coolant.

I'm now going to drop the oil and leave the drain plug open to see if the coolant will make its way out of there to confirm it is 100% the coolant leaking into the oil.

Any advice on anywhere other than the head gasket where coolant can enter the oil but not vice versa? I'd have thought an oil cooler fault would put the other way and fill the coolant. Just don't want to do such a big job and not end up fixing my problem!

[metalworker0]

There is one more place on the outside and it's the oil cooler.

Head gaskets can do strange things and act differently in every failure .. can go on for months confusing you, then fail spectacularly.

This oil cooler is right next to the oil filter, but it's usual for this to put oil in the coolant when it fails, not coolant in the oil, as the oil has more pressure than the coolant.

Head gasket can fail in many places

1. Strait into the cylinder
2. Between 2 cylinders
3. Into the water jacket

Or could be a crack in the head or cylinder liner.

and i don't know about the boxer, some turbos are water cooled.. not on the transits though

Failures of the coolant system, all can be very difficult to pin point until they completely fail .. and milky oil in this present weather and heat may be not happen because the engines high running temperature is boiling it off as it happens.


The equipment you need to rule things out
1. a coolant pressure tester - to observe the pressure as the engine starts, see if it reises sharply , or use the pressure tester to pump up the system to 15psi.. to cause leak .. and see the pressure not hold if there is a leak.
2. a compression tester.. to see if pressure is down in one cylinder .. and is leaking into the next
3. a leak down tester - to put pressure into the system
4. a boroscope to observe drips into the cylinders, when under pressure with a coolant system pressure tester
5. a sniff tester .. you've already used this ,.. but there are other maybe better ones that have a rubber bulb to bubble to coolant gas through the chemical .. also there is the garages MOT exhaust analyser probe

and the simplest methods to confirm this, are to observe what's happening.

1. Is it putting pressure into the coiling system within seconds of starting. hoses getting hard strait away
2. Are strange things happening on cool down, like collapsed hoses
3. Are the hoses still hard the next day after cool down

Another simple test is the latex glove over the expansion reservoir filler .. elastic bands to keep it on .. if it inflates from the cold engine in less than a minute .. then the gaskets gone.

As you can see .. there are plenty of ways this head gasket or crack in the head or liner problem can show its self .. and only show its self barely or weakly - AT FIRST

All these can even have seasoned mechanics confused . it can go on for months .. the above test equipment will hopefully narrow it down quickly. otherwise its a waiting game for the big event .

you need break down cover now.. AA, RAC etc .

all the best.mark