my 1997 Cherokee 4L petrol produces white smoke some times....and the mechanics don't find the cause.
the following scenario:
Driving 100km/h on a long road sloping-up and down a little with cruise control on. Suddenly the car starts smoking a whitish smoke...lots of it... and this usually after a slight up-slope when it gets flat again or the car going downhill. Sometimes, just driving straight and flat it starts producing smoke again.

Sometimes nothing happens at all for a long time...?? I checked oil levels, all OK I checked water levels and ran the engine with open cap....All Ok?? I checked gearbox oil....all OK.
When the cars smokes a lot I sometimes stop very quickly to have a look at the exhaust to see if the smoke comes from there, but unfortunately, as soon as I stop the car with idling engine all smoke disappears like magic.
thanks in advance for your opinion

 

Black smoke indicates, rich condition, bluish/whitish smoke indicates oil and white unfortunately usually means water somewhere. Are you adding any water at all. You might have a really slight head gasket seepage. If yout think you do have your mechanics do what's called a leakdown test. They put air into each cylinder and then listen for air coming out either the exhaust (bad exhaust valve), intake (bad intake valve), crankcase (bad rings), or radiator (bad head gasket and or cracked head) if it's the later then they will also see the water level rise in the radiator.

 

Hello Marcall, thanks for your advice.
when the smoke happens my rear window and the back of the car gets splattered with little droplets of oil.
I tested the water in the radiator and had to add a little bit to fill it.
then, leaving the cap open, I started the engine to see if something happened...and nothing happened.....the level remained the same. In conclusion, I don't think it's water.
I'll ask the mechanics to carry out the other tests, but so far the engine does not produce smoke when it's idling or when you rev it up....only when driving it and even then not all the time.
all the best, dirk

 

A compression test will show of it has a head gasket or head problem.

 

Mine would do the same thing............................mostly after a long uphill climb on the highway...............I'd check for oil/tranny leaks...........never found any.
Turned out to be coolant.
My top radiator hose fitting on the radiator(plastic tanks) had cracked, and it only would spray out just after I crested a large hill, just as I was letting off the throttle a little.....................a cloud would billow out behind my Jeep.
I never had to add much coolant, so I didn't think it was that..........

I found the problem while i was doing the tune-up the other night.

If your radiator has plastic tanks, check it all over for cracks, and any evidence of dried coolant that might have sprayed out around it......

 

Hi Andrewmp6 and Firehawk068,
thank you very much for your reply...I'll have all that tested very soon. If the cause of the smoky problem is found I'll definitely post it here.

thanks again and kind regards
from freezing Van Reenen in South africa.
dirk