Coolant loss part three

[penfest]

Firstly thanks to everyone for your advice.
Tcut I did the crackle test but it was a bit inconclusive I don't think the metal I used was hot enough. Now for a silly question what does the rubber pipe from the expansion tank do. When I ran the car for about fifteen minutes I noticed that there was water filling up the gap between the plastic collars inside the neck of the tank. There was nothing coming through the hole where the rubber tube joins the tank. After cleaning out the hole there is now a constant flow of water running into the tank. Would this be anything to do with my coolant problems. Sorry for such a long post.

[T-Cut]

Originally Posted by penfest

Tcut I did the crackle test but it was a bit inconclusive I don't think the metal I used was hot enough.

The oil simply needs heating well above 100C, preferably above 150C so any water contained in the oil evaporates explosively, typically making a crackling sound - same principle as frying bacon. Try putting a half ml of oil onto a kitchen foil 'dish' and apply a lighter flame underneath. That should do it.

what does the rubber pipe from the expansion tank do.

Assuming you have the later single pipe tank, it carries any air from the heads to the expansion tank neck during a manual bleed operation. The air is usually carried in a small amount of coolant so is vented off to the header tank. The side entry pipe to the header neck actually divides into two. The exit you see on the inside of the neck and a much bigger entry which you can't see. Even if the small hole in the neck gets bunged up (pretty common) it won't stop the passage of air or coolant into the header. The smaller entry gets blocked off anyway when the pressure cap's screwed on.

When I ran the car for about fifteen minutes I noticed that there was water filling up the gap between the plastic collars inside the neck of the tank. There was nothing coming through the hole where the rubber tube joins the tank.

In the V6, hot coolant typically circulates into the tank via the bleed hose. This video still shows flow from both bleed exits:




I'm not sure I understand what you describe, unless you have the older two-pipe tank. In that case, the second one was intended to direct any ejected coolant onto the ground.





This photo from inside the tank shows the hidden entry from the bleed hose:




Hole 1 is the small one you can see. Hole 2 enters the tank vertically downwards.

After cleaning out the hole there is now a constant flow of water running into the tank. Would this be anything to do with my coolant problems.

I don't think so. You have loss of coolant from the cooling system. The header tank isn't receiving that just because you freed the small bleed hole in the neck. I'd concentrate on the raised oil level to see if that's where it's going.


TC

[penfest]

Thanks for that I shall do the test again

[TourerSteve]

Originally Posted by penfest

With reference to my earlier post I am still having problems with water loss. On a recent trip the temperature gauge went nearly up to the red and the car went into limp mode. I have noticed the oil level on the dipstick has risen. There are no signs of any leakage in the engine bay, could it possibly be a head gasket failure. I topped up the coolant and the engine started as normal with no untoward noises. Any advice would be appreciated.

Look at the evidence you have already
Engine oil can only rise if not topped up by cross contamination of either fuel or coolant . How much extra fluid have you actually got on the dip stick ? Is it substantial and looking equal to volume of coolant you added , As TC quoted , OAT Antifreeze isn't always obvious in oil but if you losing one and gaining in the other there is a good chance you have cross contamination
I would suggest if you had a substantial amount of diesel in you oil you would be able to smell it
I know you are trying to carry out the crackle test and hopefully it will be conclusive this time
If you prove you have cross contamination of coolant you have then got to look for potential paths where the fluids can cross contaminate
As you have already stated head gasket is one , but historically have proved reliable but can fail obviously
The engine also has an oil cooler ,which in not an unknown leak point (admitted often's a failed oil cooler will put oil into the coolant as oil at higher pressure but can leak water into oil ) and would be my first suspect to investigate before looking at the head gasket

https://www.dmgrs.co.uk/products/rov...oler-pbc101370

[penfest]

Hi Steve thanks for your post. I have done the test again and it confirmed that there is water in the oil, is changing the oil cooler a difficult job or would it be a job for a mechanic ?

[trikey]

Changing the oil cooler is not a terrible job, starter mootor off to gain access then three bolts and a couple of water hoses and it's job done.

The issue is cleaning out the cooling system as that can be awful if there is a lot of oil in the water.

[T-Cut]

Do you see any signs of oil in the cooling system? If there are no obvious engine oil globules floating on the coolant in the header tank, can you see any bloom on it? (The rainbow effect you see on an oily rain puddle). Move your head around to get the sky light at the right angle to reflect off the surface. If there's a bloom, you'll have to drain down the cooling system and use a cooling system flushing product to clean it out. Holts RadFlush will do. If there's oil globules in there, then as trikey said, it gets more tedious .
TC

[TourerSteve]

If your struggling to check the header tank it may be easier to drain the coolant to check for oil