I have brown sum what oil looking balls/bubbles(no air in them) on top of my coolant | The Z Club of Great Britain
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I have brown sum what oil looking balls/bubbles(no air in them) on top of my coolant

Discussion in 'Z32 (300ZX)' started by Twin_Turbo300zx, Aug 14, 2009.


What is the Bron Crap on my coolant? I say on because it isn't realy mixed.

Poll closed Sep 3, 2009.
  1. Rust (Please)

  2. Curossion (or please)

  3. Oil (I'm probably screwd)

  4. Water Wetter (it was there before I added it)

    0 vote(s)
  5. Don't worry about it. (sleep well for once in the last couple weeks)

    0 vote(s)
Multiple votes are allowed.
  1. Twin_Turbo300zx

    Twin_Turbo300zx Forum User

    I have brown sum what oil looking balls/bubbles(no air in them) on top of my coolant. There is no coolant in the oil and I am not loosing any oil. In the morning when it is cooler there is some white smoke but only for a minute or two during the day it runs clean(no smoke).:driving: I don't have a noticeable loss of power. I do have a coolant leak I have to ad coolant once or twice a week.

    Any Ideas on the brown stuff? Could it be rust or corrosion?

    Also I recently replaced the thermostat and cleaned the radiator out as best I could. The sludge is only on the top and in the radiator and the overflow the rest is clean.
  2. zpuppy

    zpuppy Well-Known Forum User

    Hiya twin ! Don't give up hope mate, but with white smoke on cold starts it does point to coolant being burnt in the combustion chamber.sounds like a head gasket to me to be honest,,but caught in time doesnt need to be expensive . :thumbs:
  3. Twin_Turbo300zx

    Twin_Turbo300zx Forum User

    I was starting to guess head gasket. The thing is the smoke smells like gas really bad on cold starts so I was just figuring it was running rich...? And I think its going to be expensive either way... I guess that's what I get for driving a sports car.
  4. datty240Z

    datty240Z Well-Known Forum User

    If you or anyone else has ever used Radweld or similar it is really difficult to get rid of and aswell as sealing the leak it blocks up the various valves and heater matrix in your cooling system. But one of the consequences is the brown bubbly sludge that you talk of. I know from bitter experience when I used it in an emergency in one of my Dattys.
  5. Twin_Turbo300zx

    Twin_Turbo300zx Forum User

    If I post a picture do you think you would recognize it?
  6. datty240Z

    datty240Z Well-Known Forum User

    Possibly, in my car it looks a bit like a melted chocolate Aero only watery (and bubbly ofcourse).
  7. Lets Drift

    Lets Drift Well-Known Forum User

    If you are burning coolant it will have a slight sweet smell to it.

    It's normal for cars to show a wee bit of white smoke on start up on a cold morning it's condensation burning off.

    However if you do have a coolant leak get it sorted you don't want the possibility of overheating and blowing your engine.

    My coolant as brown and slightly bubbly and sank like stagnant water till I did some nice coolant flushes.

    I did it 10 time's, 3 time's with a weak solution of bicardonate of Soda, 4 time's with water, Then I used the Holts Rads stuff.

    Best to check the radiator and all the couplings and hose's for leaks.
  8. Twin_Turbo300zx

    Twin_Turbo300zx Forum User

    So I am pretty sure that the fluid is oil (it feels oily but doesn't have much of a smell). My oil is still clean the car had some stuff done before I bought it. They did the bearings and who knows what else. I don't want to jump the gun on a blown head gasket.

    There are other possiblities on the oil in coolant right? My car has and oil cooler on it is that stock? does coolant run through it or is it air cooled. Could the turbos somehow mix oil into coolant with out coolant into oil? There is a possibility it was there before a fix and just hasn't been cleaned out because there is a small amount and I'm not losing oil.

    I am going to fix the leak and clean out the radiator as best I can, any suggestions on how to clean it when its not in the car?

    My next step is a compression test.

    Does anyone know any good shops or what it would cost for the head gasket? I really don't want to do it myself if that is the problem, but I don't have a very deep wallet so....

    Thanks for your help.
  9. datty240Z

    datty240Z Well-Known Forum User

    Surely oil in your coolant does not produce a brown bubbly residue but more of a creamy coloured thick sludge. Thats what I always thought and thats what you always see inside the oil cap of cars with dodgey head gaskets. I would def clean out the system several times before doing any thing too rash. As mentioned before bicarbonate of soda is supposed to be good for this.
  10. Twin_Turbo300zx

    Twin_Turbo300zx Forum User

    So I did a compression test and got 105 to 120 that seems low..? I know my first gen DSM was 125 minimum. I will post pictures of spark plugs and every thing tonight. For some reason I can't find a coolant pressure tester that fits my radiator. I .will order one online asap.

    Thanks again for every ones help.
  11. Twin_Turbo300zx

    Twin_Turbo300zx Forum User

    From radiator cap and radiator


    radiator cap

    from dip stick


    Second test on 4 no oil added just retested probably didn't tighten it enough the first time

    Spark plug 6

    Spark plug 6 pressure 6

    right intake mani a little oil in there probably from turbo seals

    Spark plug 5

    Spark plug 5 pressure 5

    left intake manifold also some oil most likely from turbo seals

    Spark plug 3 pressure 3

    Spark plug 1 pressure 1

    Spark plug 4 has some oil on the top?

    Spark plug 4

    Spark plug 2

    Spark plug 2

    Spark plug 2

    Last edited by a moderator: Aug 18, 2009
  12. Lets Drift

    Lets Drift Well-Known Forum User

    Just run water with bicarbonate of soda throught the radiator.

    But don't forget you need to run it through the whole system this can only be done with the radiator connected and the engine running so it come's up to temputure.

    If you have yuk in the radiator it'll be all through the cooling system and you'll need to clean it all out.

    I have seen people run a hose into the top of the radiator and open the bottom release valve but that will only flush out the radiator and not the whole system.

    If your zed is any thing like mine that release value (underside of radiator driverside) will not open that well and will take hours to empty. I had to keep uncoupling and recoupling the hose on the other side at the bottom.

    Here's how I did it. Zed and the Coolant Flush - JapGirls

    All the best hope you get it all out and find all the leaks and are able to sort them out.


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