Why would my antifreeze have oil or transmission fluid in it?

Asked by kubehead Apr 10, 2009 at 03:12 AM about the 1994 Mazda MPV 3 Dr STD 4WD Passenger Van

Question type: Maintenance & Repair

About a year ago I replaced the radiator&put in a refurbished one.Around the same time I had to get the transmission rebuilt.Its ran great up untill a month ago,it overheated,so I checked the antifreeze level in the resivore & noticed it had a dark oily substance all over the inside of the resivore.I dont have any oil leaks im aware of.
Any info. or ideas on what I should or could do would really be appreciated.
Thank You,Mark S.

3 Answers

30

has nothing to do with the transmission just make sure theres no antifreeze in the engine when u pull out the dipstick

2 people found this helpful.
110

It may be the case that your refurbed radiator has a breach between the engine coolant and transmission fluid sections.In this event, it would have *everything* to do with the tranny. Many cars/vans route the transmission fluid through a lower portion of the radiator for cooling. If there is a hole and the two mix, the transmission fluid would float to the top of your radiator and be discharged into the coolant reservoir as overflow. If you replaced the radiator first and then experienced a transmission failure, that is likely the cause. I realize this answer is probably a bit late (4yrs), but if someone is experiencing a similar issue it may help. Bit of advice...when it comes to radiators, best to buy new.

11 people found this helpful.
180

I have milky brown oil in the coolant reservoir, what could it be?

10 people found this helpful.

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