gibbon Posted September 6, 2009 Share Posted September 6, 2009 Hi everyone, my oil sure is watery all of a sudden. here's the back story; having to move house, but not very far, i decided to risk it and drive my project RB20DET 280zx to the new place rather than tow it. thought it was time for a road test anyway. at the last minute i realised i'd forgotten about the numerous water lines on the inlet side of the block. So I looped these pipes into each other, with the belief that this would stop all the leaks. No problem, right? Anyway, I make the drive, the car runs well (hooray). I leave it at the new place for a couple of weeks and dont really drive it again until now. Decided to change the oil and WOW. I've got caramel oil and a milkshake brewing under the rocker cover. It's all the symptoms of a blown head gasket - I know. But I can't help but wonder if I had accidentally looped an oil line into a water line or something like that when i was rerouting all that piping. So long story short - Are there any oil lines on the inlet side of the block, or are they all water? Cheers in advance. Quote Link to comment Share on other sites More sharing options...
Careless Posted September 9, 2009 Share Posted September 9, 2009 There can be a number of reasons for the mayonaisse in your oil, but all return to moisture. Did you leave the oil cap off? Did you leave a vent line off? Did you have very humid days and possibly left these off during that time? There should be oil lines on the block that go to the turbo, but they are threaded lines that accept Banjo fitting bolts. The only oil passage that takes a hose would be the sump oil return line, and the only other non-water hose would be the PCV or vacuum/EGR system on some cars. At least that's what I remember from ordering all the RB parts. Raff Quote Link to comment Share on other sites More sharing options...
gibbon Posted September 10, 2009 Author Share Posted September 10, 2009 hi mate, thanks for the reply -since my last post i've pulled the inlet manifold off, and yeah its all water lines on that side. the oil feed lines on the turbo are both on the exhaust side of the engine. so doesnt look like its a case of stupidly mixing lines up. not sure what you mean by a 'vent line'. like the rocker cover vents? or something else? aside from the new oil, the engine has sat for a few years in various states of dismantled-ness. its entirely possible that moisture had built up inside, but i would have thought that the 2 or 3 oil changes ive done during that time would have negated that? ive also had the engine running for short periouds of time previously, and never noticed any oil/water mixing. (this was the first time i really ever ran it up for an extended perioud though). how long does it take for the oil and water to turn into that froth? also, the oil was nasty but there was hardly any oil in the water at all, just the slightest bit of discoloration at the top. which argues in favor of moisture building up in the sump.. looks like it could be either at the moment i guess, going to borrow some bits and pieces for a leakdown test this weekend. cheers Quote Link to comment Share on other sites More sharing options...
Careless Posted September 11, 2009 Share Posted September 11, 2009 (edited) yes, rocker cover vents. i had mine open for a while and moisture built up in the cap. you may get good results from running a cleaner like auto-rx, or even b12 chemtool to remove any varnishing of old oil and dry the remaineder of the oil gallery and what not. can't guarantee it will repair a moisture leak... its weird how it's still there. is there always MORE under the oil cap when u take it off? Edited September 11, 2009 by Careless Quote Link to comment Share on other sites More sharing options...
gibbon Posted September 11, 2009 Author Share Posted September 11, 2009 hi again, cheers for the reply. the engine doesnt have pcv lines - it came with little baby filters on top of each pcv valve - im sure they do nothing to keep air/moisture out but surely the valves would manage that. (unless theyre buggered too - havent tested that) i havent run the engine since i noticed the foam buildup, so i cant say if theres more buildup there. it seems odd to me that i never noticed anything all the times i ran it up, and then all of a sudden theres heaps of foamy stuff, but no other symptoms. perhaps it does require a certain amount of running time/temperature to really starting forming borrowed a pressure tester off of a mechanic today, he told me that if anything it should be oil getting forced into the water, not the other way around, that water that enters the combustion chamber will get sent out the exhaust via steam, it shouldnt really be able to get into the sump or oil galleries. so yeah, it sounds like i might get lucky with a couple of engine flushes/cleaners etc and an oil change. will have to keep an eye on it Quote Link to comment Share on other sites More sharing options...
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