Hi,
After some advice from any mechanically minded people
ive got a euro 5 scania 620 v8 that keeps putting oil into the water somehow, its visible when the cap is taken of the header tank there is oil all over inside of tank and a thick layer floating on the water. It all collects in header tank, if water is drained from bottom radiator hose the water is clear of oil.
So far weve replaced, oil cooler and housing, front timing casing seals and still no joy.
I have recently had this on my Transit, Oil in the water floats to the highest point - the header tank
This was the oil cooler which has been replaced, I see you have replaced yours, but did you fully flush out the cooling system?
I understand that once the problem has been cured, there will still be residual oil in the system which takes a while to get out.
It may be that the problem is solved and this is just the residue finding it’s way up to the header tank.
I would consider keeping an eye on it & keep soaking it up with a paper towel until it clears?
If there was a lot of oil in the system, there could have been some hose degeneration, and could be a oil still hiding in places like the heater matrix.
^^
Very sound advice. The time and effort required to clean out the system properly easily exceeds by a considerable margin the time to renew the oil cooler. Oil residue can reappear quite some time after the job has been completed. If significant oil is still getting into the coolant then not only will oil disappear from the sump, but the coolant reservoir will overflow. Should you be certain that there is a continuing problem then before going to the extent and potential considerable expense of removing any engine cylinder heads, it may well be best to confirm that all is tickety boo with the oil cooler renewal; it is very easy to trap or nick O rings or to damage gaskets.
Coolant system hasnt been fully flushed out, might be worth doing.
We run u 7 scanias all v8s and most have had oil in water at some point, usually either cured by replacing oil cooler, cooler housing or front timing casings seal but this one is nkt playing ball.
We have been advised to replace compressor next, might be worth trying the gasket first.
We thought we had cured it when we replaced seals on timing casing at the weekend as there was an o-ring that looked very brittle and dryed out between an oil and water port, think i will run it for another week and keep draining header tank because like you say could just be trapped oil going to header tank.
Its more likely oil residue left over from the seals going on the oil cooler. What you need to do to flush it out is drain the system and pour in around half a litre of washing machine liquid (Persil or similar) refill with water and run it for a while. The detergent will clean the entire cooling system and keep any oil residue suspended. Drain and refill with plain water, run again until hot, drain again and this time refill with water/antifreeze.
Merely draining the header tank isn’t going to do anything, it needs to be cleaned out and that means using a chemical of some sort, be that a soap or a degreaser. It is exactly the same as doing the washing up, you can’t clean greasy dishes with just plain water, even if it is hot.
Mi16ewen:
its visible when the cap is taken of the header tank there is oil all over inside of tank and a thick layer floating on the water. It all collects in header tank, if water is drained from bottom radiator hose the water is clear of oil.
Can’t help with the repairs or give advice, but i can give you a little science lesson.
You header tank will be the highest point in the coolant system, and oil is more dense then water, so will naturally find its way to the highest point
Right ok, will give it a good flush out this weekend and drive it for another week and see how its lookin. Just seems like to much oil to be just left over oil but we’ll see.
Weve never had to open any of our v8 engines in the past and some have done moon mileage with very little bother.
Mi16ewen:
Right ok, will give it a good flush out this weekend and drive it for another week and see how its lookin. Just seems like to much oil to be just left over oil but we’ll see.
Weve never had to open any of our v8 engines in the past and some have done moon mileage with very little bother.
Scania reckon it could be a cracked block!
Drive it with a good dose of washing liquid in there, it wont harm any components and is the best thing for cleaning out a cooling system of oil.
Re a cracked block, with an all iron truck engine i would think this highly unlikely…
Ps- does it have a water cooled turbo? If so it could possibly be a crack in the bearing housing/ water jacket causing the contamination…just a thought…
It sounds like residue, if it was new oil getting in then it wouldn’t be floating on top, but an emulsion and you would be losing oil and gaining coolant.
AndrewG:
Its more likely oil residue left over from the seals going on the oil cooler. What you need to do to flush it out is drain the system and pour in around half a litre of washing machine liquid (Persil or similar) refill with water and run it for a while. The detergent will clean the entire cooling system and keep any oil residue suspended. Drain and refill with plain water, run again until hot, drain again and this time refill with water/antifreeze.
As said here - if it is just oil on top a cup of persil should do it (other brands are available) - if the oil & water are like treacle (dip a screwdriver in and draw a circle and pull out) then you have a problem
Mi16ewen:
Right ok, will give it a good flush out this weekend and drive it for another week and see how its lookin. Just seems like to much oil to be just left over oil but we’ll see.
Weve never had to open any of our v8 engines in the past and some have done moon mileage with very little bother.
Scania reckon it could be a cracked block!
You have not mentioned the quantity of oil nor its consistency. It’s your vehicle and you have to do what you think is right, but I would not be sending a vehicle up the road for a week if I had doubts about it. Keep it on local work so that you can monitor it daily. I would be wanting to know from them why Scania would be saying that it may have a cracked block, rather than the seemingly more obvious cracked cylinder head or head gasket failure. Their reply may well point you in the right direction. There is a possibility that there may be some external indication of the source, other makes of engine are known to exhibit tell tale evidence.
Mi16ewen:
its visible when the cap is taken of the header tank there is oil all over inside of tank and a thick layer floating on the water. It all collects in header tank, if water is drained from bottom radiator hose the water is clear of oil.
Can’t help with the repairs or give advice, but i can give you a little science lesson.
You header tank will be the highest point in the coolant system, and oil is more dense then water, so will naturally find its way to the highest point
Exactly, never heard of pouring oil on troubled waters? Oil floats so will always be at the top, that fact that clear water comes out of the radiator drain means nothing.
There are several ways of checking for a breach in the water jacket.
To prove the integrity of the cooling system, there is a pump device with a pressure gauge to pressurise the system, then check for pressure loss. A pressure drop only proves a fault in the cooling system, oil in the water points towards a water/oil interface,ie. head gasket, oil cooler, compressor head gasket.
newmercman:
It sounds like residue, if it was new oil getting in then it wouldn’t be floating on top, but an emulsion and you would be losing oil and gaining coolant.
^
This
If the water level in the header tank is staying the same then its going to just be residue from probably the oil cooler which you changed anyway. An increase in the level in the tank and a thick emulsion floating on top points to other problems.
If the level stays even, flush the system out with the method i suggested and go from there. This is the cheapest easiest option to go for first without further dismantling.