eyefi Posted August 18, 2002 Share Posted August 18, 2002 since my decat i have been getting a puff of smoke from the exhaust. its a greyish blu colour and it smells. it happens if i blip (just 500rpm or so) the throttle at idle (it takes a second or two to exit the exhaust) and when setting off from junctions. this doesnt happen all the time. im running a 5-40 engine oil but cant definately say how much is being used, is this too thin? there is also a little oil in the charge air pipe, its not soaked. my plugs are nice and buff, and dry. it also does a little puff of smoke on cold start. im not aware of any smoking when driving except for the usual black puff on wot. the car has 70k miles and does not overheat. apparently decat can show up turbo seal wear that was previously invisable because of the lack of backpressure on the worn seal. i would be interested in opinions as to whether this is turbo oil seal or valve stem seals, or (dramatic music) both. ive seen some of the mkiii guys repairing the turbo seal with a kit, anyone done this? is it a good idea? whats the differance between ignited and burnt oil and superheated oil out of the exhaust. i know the celica gt4 smokes white when the turbo seals go. so is superheated oil smoke white and burnt oil blue and smelly? i think its valve seals. ta Quote Link to comment Share on other sites More sharing options...
Guest Nick Harris Posted August 18, 2002 Share Posted August 18, 2002 5w-40 is too thin fro the Summer, you should be on 15w-50 or even 20w-50. You can score the bores with oil that is too thin. Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 18, 2002 Author Share Posted August 18, 2002 nick - can u expand on that a bit further. r u saying my bores maybe scored and that could b the problem or that the oil is just too thin and escaping past the seals. why might light oil cause bore score? the stock oil weight is 10-40. Quote Link to comment Share on other sites More sharing options...
Syed Shah Posted August 19, 2002 Share Posted August 19, 2002 Originally posted by eyefi the stock oil weight is 10-40. I thought it was 10-30?? Quote Link to comment Share on other sites More sharing options...
Alex Posted August 19, 2002 Share Posted August 19, 2002 It might say 10-30 on the engine but try finding someone who runs it!! Nick, So 5W50 is ok for the winter I assume because of the potential sub zero starts? Have you actually seen this scoring on a 2JZ engine??? Is there a web site with some pictures of a 2JZ that has suffered from oil that's too thin. Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 19, 2002 Author Share Posted August 19, 2002 the more i think about the oil weight the more it makes sense, it all adds up. ive got some mobil motorsport 15-50 and im putting it in tonight. ill let u know the results. anyone want to buy some 2nd hand 5-40, only 200 miles on it. buyer collects Quote Link to comment Share on other sites More sharing options...
scooby_doo_do Posted August 19, 2002 Share Posted August 19, 2002 Sounds very familier to my car at the moment. Exactly the same problems... I've changed the oil on my car twice in a week with no affect. Still smokes up like a good'n when i come to a stop.. But it only does it every now and then which is annoying. Doesn't smoke on startup though... I was running mobile 1 0-40 but then changed to 5-50. The cars been running fine but the garage i took it too advised going for normal fully sync as he said it was too thin otherwise. Still don't know if its the o-rings or the turbo's..he said just drive it until it gets worse and then well decide again... sob sob... Craig MKIV TT 6. Both Cats removed, S-AFC, S-AVCR, FSE power Boost valve, Apexi Super air intake, Samco hoses, HKS sparks, Blitz dump valve, Tein suspension, RLTC, Carbon clutch, EBC brakes. Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 20, 2002 Author Share Posted August 20, 2002 changed the oil, no smoke on startup and greatly reduced blip of throttle smoke. Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 20, 2002 Share Posted August 20, 2002 A thin 5w oil will have a tendency to leak around worn valve seals etc.. I used to use 20w in my old MkIII as it was a bit of a bagpuss. A 10w should be OK in a MKIV engine unless it's ancient. Not sure what effect running a soupy 20w will have No idea why ambient air temperature should affect the oil's consistency to a degree that you need 'winter' and 'summer' oils. I would have thought that the oil companies would soon be marketing this to shift more oil out the door After all, you can get a 20degC variation in temperature from one week to the next no matter what season it is in this country! -Ian Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted August 20, 2002 Share Posted August 20, 2002 Originally posted by Ian C No idea why ambient air temperature should affect the oil's consistency to a degree that you need 'winter' and 'summer' oils. I would have thought that the oil companies would soon be marketing this to shift more oil out the door After all, you can get a 20degC variation in temperature from one week to the next no matter what season it is in this country! -Ian I would guess more or less protection during startup. Unless of course you are using that new fangled whizzo magnatec stuff. Quote Link to comment Share on other sites More sharing options...
HedgehogSandwich adi Posted August 20, 2002 Share Posted August 20, 2002 My early symptoms of turbo seal were as follows for comparison. :Couple of seconds after a blip at stand still smoke would come out, hang around in a wispy kind of way (only after a long run). :Smoke when sitting at traffic lights, particularly after a hard run. Would continue until i drove off again, or carry on until the engine is turned off. I never used to see any smoke when driving, only at speed on an O/D kickdown. adi Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 20, 2002 Share Posted August 20, 2002 Anyone with mechanical sympathy must love that advert - I know I wince I thought wear at startup was due to oil draining away from the frictional surfaces of components - hence the magnatec advert based around it 'sticking' to the metal. Besides, if an oil is too thin to provide protection when cold, what's it like at normal running temperature?! Oil becomes thinner the hotter it gets, as far as I recall So, the thinner the oil, the better your engine tolerances have to be at normal running temperature. For old, baggy engines, have a syrupy 20w. For the showoffs, have a 0w I still can't see how the ambient air temperature affects your oil grade requirements so dramatically? (how hot is the oil at normal running temperature, btw?) -Ian Originally posted by Martin F I would guess more or less protection during startup. Unless of course you are using that new fangled whizzo magnatec stuff. Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted August 20, 2002 Share Posted August 20, 2002 Originally posted by Ian C Oil becomes thinner the hotter it gets, as far as I recall Yep that's what i mean. If your car is sitting on the drive in summer (a real summer not a UK one) then the engine and associated components would be warmer than in say February. Therefore if you had a thin oil in (say 5w-40) all the time you would have more protection in the winter than what you would have in the summer, due to the viscosity of the oil being thicker in the winter than the summer. If you went for a slightly heavier oil (10w-40) then you would have more protection in the summer than the example above. As for protection, the thicker the oil the greater the protection between journals and bearings, cam followers and lobes, etc. Due to the fact that there should be a layer of oil between these various surfaces. This would obviously be of greatest benefit at startup from cold where the viscosity of the oil is going to determine how well it would have managed to stay coated to surfaces. Well that's my theory, probably very flawed, but i would be happy for somebody in the know to explain this one. Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 20, 2002 Author Share Posted August 20, 2002 http://www.mkiV.com/techarticles/oil/oil.htm http://www.ferrariclubofamerica.org/techtips.html http://www.fernblatt.com/longhurst/engineoil_bible.html Quote Link to comment Share on other sites More sharing options...
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