Davemate Posted March 11, 2012 Share Posted March 11, 2012 I put the same oil in both my car and the wife's The wife has driven about 3miles a day since last August and the oil still looks like its in the can Last Saturday I did a oil and filter change on my car then on Sunday I drove to stoneliegh and back,200 miles and my oil is black Why does oil turn black ? Link to comment Share on other sites More sharing options...
drofgum Posted March 11, 2012 Share Posted March 11, 2012 Dave,Oil turns black for a number of reasons. In an older car perhaps the quickest thing turning the oil black is picking up contaminants that are in the engine already. New contamination is primarily carbon from combustion and coking of oil. A very minor component is extremely fine metal particles, but this is never enough to colour the oil if it is changed. The oil in a gearbox would have some metallic contamination, but it rarely is black on draining. Cheers, Paul Link to comment Share on other sites More sharing options...
Steve Cureton Posted March 11, 2012 Share Posted March 11, 2012 It might be worth dropping the sump and cleaning it out as they do accumulate sludge over the years which will discolour new oil. Also worth doing an engine flush using either cheap oil or a proprietary flushing oil. Link to comment Share on other sites More sharing options...
Clive Posted March 11, 2012 Share Posted March 11, 2012 Agreed, all the engines I have taken apart (except those I know have been rebuilt etc) have had an unhealthy layer of tar-like oil in the sump. I guess this contaminates the fresh oil pretty fast.If you are bothered, as above drop the sump and clean it out. I don't think I would be inclined to use an oil flush additive, it may spread the crud around the engine. Otherwise leave until you need to drop the sump. Link to comment Share on other sites More sharing options...
Davemate Posted March 11, 2012 Author Share Posted March 11, 2012 I'll drop the sump and have a clean--once the weather warms up a bit I'm in no rush Link to comment Share on other sites More sharing options...
Clive Posted March 11, 2012 Share Posted March 11, 2012 Be warned, once in there you WILL be very tempted to have a look at the big ends. In fact, it would be silly not to! And then...... Link to comment Share on other sites More sharing options...
Davemate Posted March 11, 2012 Author Share Posted March 11, 2012 That's why I'm in no rush !!!!! Link to comment Share on other sites More sharing options...
GT6 M Posted March 11, 2012 Share Posted March 11, 2012 also blow by will effect the stuff.And also how hot your oil got.what oil did ye put in,!!! a moer moder oil,!! if so,it will be softening alsorts up,so making your new oil dirtier faster.older oils did no keep the dirty stuff in suspension, so it settles in the sump.thats why as Clive says,its tick in there, some times 12 an inch tickthe older type filter did no like it ,so thats why oil had not the dispersants in itmodern oils have alot of didpersants,and the filters are diff to, so the stuff is carried into filter,and held there.take a filter to bits, and its like gooey tar in there.so istead of being int sump,its int filter.M Link to comment Share on other sites More sharing options...
Davemate Posted March 11, 2012 Author Share Posted March 11, 2012 I use a 20/50 oil cant remember the make,it's just whatever the local macces have on specialmy local Carspares don't stock it so i buy a couple of 5 ltr cans when I go to macces every so often.I don't have any rattley ends and my pressure is quite good Can the sump be dropped and the shells changed with the engine in situ,if I decide to do the shells that isIt's a 1500 in a herald ? Link to comment Share on other sites More sharing options...
Clive Posted March 11, 2012 Share Posted March 11, 2012 Shells can be done with the engine in, but it will probably need jacking up a bit, which probably means the rad needs either hoses off OR unbolt the rad so it lifts with the engine.Best to wait until you have checked the bearing size if you plane to fit new bearings. Possibly std size, but could be anything. Link to comment Share on other sites More sharing options...
Davemate Posted March 11, 2012 Author Share Posted March 11, 2012 A job for the warmer weather Drop sump,check shell size,order shells,clean sump then fit new shells and return sump to its home And if I can get my unleaded head skimmed I could fit that at the same time If the heads off and the bottom dropped I could then fit a new cam and,Hang on I only asked why has my oil has gone black ! ;D Link to comment Share on other sites More sharing options...
JohnD Posted March 11, 2012 Share Posted March 11, 2012 If you wish to know more about oils, can't recommend this book enough:http://www.veloce.co.uk/shop/products/productDetail.php?prod_id=V4365&prod_group=Performance Tuning & Modification&JohnSorry, doesn't link directly, but go there and search for "Which Oil?" Link to comment Share on other sites More sharing options...
Davemate Posted March 11, 2012 Author Share Posted March 11, 2012 Cheers John One of my mates works in the engine oil business and from what he bores us with down the pub withI know there a lot more to oil than most people think Link to comment Share on other sites More sharing options...
StagNL Posted March 11, 2012 Share Posted March 11, 2012 What does the wife drive? Does it run on LPG? LPG is known to keep oil looking fresh for a long time. Link to comment Share on other sites More sharing options...
Davemate Posted March 11, 2012 Author Share Posted March 11, 2012 699 wrote:What does the wife drive? Does it run on LPG? LPG is known to keep oil looking fresh for a long time.Apart from me around the bend !It's 64 convertable herald Link to comment Share on other sites More sharing options...
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