what would cause oil to thin out

[navara66]

On the way back from hampton downs towing a race car my td27 turbo d21 navara started making a real racket, we stoped and checked the oil and it was thin as water.
This oil is under 5000km old, Truck has done 175km and has water injection. Could it have a small amount of blow by causing water to get mixed with the oil. The water injection nozel is a bit big 300cc but doesent bog down when running.I will do a compression test this week to see if that is the problem,in the mean time i have done a oil/filter change but with no oil preasure gauge i wonder what damage has been done.
Does anyone have any other thoughts on what caused this problem.

[kbushnz]

What brand and grade of oil???

[sibainmud]

Front seal on the injector pump. Just a suggestion.
If water was mixing with the oil you would have lots of grey sludge.
Diesel thins oil quite well. Was there more oil in it than normal?
Otherwise the rings could be shot and raw fuel in getting down to the sump.
Cheers,

[navara66]

Valvoline diesel extra 15-40
when i let it sit the oil level was on half.When we stoped on the way back from hamptons downs you could see specs of water on the dip stick.

[ClassicCruiserSpares]

Maybe you blew a head gasket.

[sibainmud]

I'm starting to think we are only getting half the history and symptoms to work with
Any info you can feed us helps get to the bottom of the problems
Cheers,

[kbushnz]

Valvoline diesel extra 15-40

It will get quiet thin when hot...
You say you were towing the race car...when it happened.
I suspect you have pushed her a little too hard and something has let go...
Big ends come to mind....
I think your oil condition when it went is a red herring....
Is it still noisy????

Calvin

[navara66]

I'm starting to think we are only getting half the history and symptoms to work with
Any info you can feed us helps get to the bottom of the problems
Cheers,

Do you want my life story,we were doing 80-90kph up there in a train parked up for 8 hrs then started 10min after we left. The oil was like piss today so we changed it. water temp didn't even get to half and about 500deg on egt gauge.

[navara66]

Valvoline diesel extra 15-40

It will get quiet thin when hot...
You say you were towing the race car...when it happened.
I suspect you have pushed her a little too hard and something has let go...
Big ends come to mind....
I think your oil condition when it went is a red herring....
Is it still noisy????

Calvin

Not as noisy once oil change was done,I think it may have been starving the topend and it was noisy tappits. but don't have an oil preasure gauge.

[sibainmud]

I'm starting to think we are only getting half the history and symptoms to work with
Any info you can feed us helps get to the bottom of the problems
Cheers,

Do you want my life story,we were doing 80-90kph up there in a train parked up for 8 hrs then started 10min after we left. The oil was like piss today so we changed it. water temp didn't even get to half and about 500deg on egt gauge.

Settle down there fulla.
Your life story can wait till I get to know you
Some things you have said are a bit strange, that's all.
Water and oil don't mix, they emulsify. So if you are getting water droplets at the top of the dipstick there must be droplets under the oil filler cap, if not then grey emulsification.
Water tends not to make oil thin, from my experience it gets thinker and changes colour slightly.
Now you have mentioned that the water injection nozzle may be little large and we aren't familiar with your set up (when it comes in or out).
Did you take a sample from mid flow when draining the sump to do an analysis on? That would take away all the guess work, not only on the possible cause but also the possible damage too.

Sorry for getting ya hackles up

Cheers,

[pressy]

could you have diesel in the oil, as in the pump leak internally . does the oil smell like fuel(diesel)?

[crazyclark31]

yeh i would be tempted to say fuel has mixed with the oil.
Have found from experiance that valvoline oil isn't up to the task in turbo trucks.Esp when worked hard.
Change to delo 400 and my oil pressure probs went away and the motor ran quieter.

[navara66]

Sorry we didn't get a sample mid flow, it was so thin it was spraying every where. We just got the hell out of the way.after talking to my brother he said there was a slight smell but it didn't smell like diesel, He thought it smelt more like meths from the water injection, but i have a head cold so carn't comment.

[3VILC]

My safari used to have pressure problems when warm used to fluctuate up and down when using that valvoline diesel xtra, changed to even that cheap calibre formula diesel from supercheap and it went back to normal

[DDAN]

Are you running meths or methanol, ive been running methanol injection for over 60,000 km no problems just a really clean engine so dont think it will be that.

[navara66]

Are you running meths or methanol, ive been running methanol injection for over 60,000 km no problems just a really clean engine so dont think it will be that.

Just 50/50 water meths.

[navara66]

Did a compression test
310 psi
310 psi
290 psi
290 psi
Truck still goes very good but the lower limit is 350 psi.

[IanB]

Did a compression test
310 psi
310 psi
290 psi
290 psi
Truck still goes very good but the lower limit is 350 psi.

Compression test results can be affected by numerous factors:
-engine temp
-was throttle held open or closed when testing
-tester used (may not all read the same)
-atmospheric pressure
-how many rotations of engine
-etc

The actual numbers are not what's important, you want the cylinders to be within 10% of each other (which they are, but just barely).

[navara66]

Did a compression test
310 psi
310 psi
290 psi
290 psi
Truck still goes very good but the lower limit is 350 psi.

Compression test results can be affected by numerous factors:
-engine temp
-was throttle held open or closed when testing
-tester used (may not all read the same)
-atmospheric pressure
-how many rotations of engine
-etc

The actual numbers are not what's important, you want the cylinders to be within 10% of each other (which they are, but just barely).

- engine had just been driven
- the throttle was closed and fuel cutoff was unpluged
- we used an exspensive 1000psi tester
- rebuilt starter cranked till the gauge stoped.

[TD power]

havent had much to do with these engs haha i would say fuel pump is leaking fuel in to oil