IM A FLEET MANAGER AT A TRUCKING COMPANY TRYING TO FIND IF ANY HARM WILL COME FROM PUTTING HYDRALIC OIL IN AS ENGINE OIL FOR A SHORT PERIOD...OUR NEW OIL COMPANY HOOKED UP THE OIL LINES IN REVERSE SO WE WERE PUTTING HYDRALIC OIL IN THE ENGINES AND ENGINE OIL IN THE HYDRALIC

I think I got the impression about how bad it was, even without the all caps!

It would help to know what engines, how long, what kind of loads, what oils, etc.


Under no load, there would be minimal, if any damage. Under load...well, hydralic oil probably approximates a 20W20 motor oil...without anywhere near the additive package of motoroil. Mixed in with motor oil as a top up...well, it would definitely be less serious.

Obvioiusly, change and dump the motor oil immediately. I would, if at all possible INSIST that the oil company pay for that, and a series of used oil analyis reports to check the engine condition. If possible, make them get the hydralic fluid that was in the engines analysed also.


Even if the oil company balks, if you have to pay for the oil analysis reports out of pocket, I would still get some, espicially if you can get samples of the contaminated oil from the engine(s)...if it shows high wear metals, you'd have some serious leverage with the oil company!

This is an interesting and can be really classic real life situation.

1. Engine oil as Hydraulic oil: No real harm done, except for higher costs and higher detergency.

2. Hydraulic oil as Engine oil: This is a difficult one.
i) Presumption top up is 2 to 5%: If your fleet works on a hilly terrain take first opportunity to drain if oil has reached 75% of life ( if truck on 5,000 km drain life, drain at 3750 km or thereabouts.)
ii) Presumption top up 2 to 5%: If fleet operates on flat terrain but you use an long drain lubricant, take first opportunity to drain if oil has reached 75% of life ( if truck on 10,000 km drain life, drain at 7500 km or nearest to that limit)
iii)Presumption top up 2 to 5 %: If fleet operates on flat terrain drain at normal lube life, but increase top up if possible.

These are rule of thumb only but be vary of any complaints. If so take action immediately. As suggested by Abus please seek analysis report of used oil from Lube suppllier for all doubtful cases.

Hussam Adeni

1# Engine oil in Hydraulic system:

May not cause much harm during shorter periods

2# Hydraulic oil in Engine :

Depends upon load and operating conditions...
drop in viscosity would lead to adhesive
wear.Cut open lube filters for large metallic
particles.If metals observed,get it fixed
immediately to aviod catastropic failure.

Bala.

Flintstone

Hydraulic oil in engine that's dangerous.
I hope you have used a ISO VG 68 viscosity oil in your hydraulic system.

Do an anlaysis of the oil present condition or else replace the engine oil.

Engine oil in hydraulic system shouldn't do any harm in the short run.

When you do the oil analysis on the hydraulic oil, do a particle count test. The engine oil may have cleaned a lot of gunk out. You may have to change it again to make sure it's clean, and of course the filters.

Jon V

I had suggest an Oil analysis to know the condition of the engine and not the oil .

I feel you should more worried about the engine than the oil. Please do a complete flushing and charge fresh oil along with new filters in order to remove the gunk generated due to the old oil.