Excessive oil consumption - high mileage
09-28-2017, 06:02 AM
#11
Higher grade (thicker) oil is not a panacea for curbing oil consumption as there can be unintended consequences.
At normal engine operating temperatures 10W-30 "grade" oil is what the engine is designed to run on and provide the necessary oil flow for lubrication. Oil flow is critical. Since 5W-40 is an alternate that's fine too. Going to something higher if still in the normal engine operating temperature will not provide the oil flow needed to lubricate the rest of the engine. Engine temperatures in race cars can far exceed normal and require a higher oil grade.
I'd look at several different multigrades in the 5W-40 range. Mobil 1 is notorious for oil consumption which indicates to me there will be brands/formulations that have more oil control than average.
A catch can is dirt simple to add and will isolate breathers as an issue. There are some dual cans which will further pinpoint where the oil comes from. Won't be any in the cans, though, it if's going out the exhaust via the rings.
-- Chuck
At normal engine operating temperatures 10W-30 "grade" oil is what the engine is designed to run on and provide the necessary oil flow for lubrication. Oil flow is critical. Since 5W-40 is an alternate that's fine too. Going to something higher if still in the normal engine operating temperature will not provide the oil flow needed to lubricate the rest of the engine. Engine temperatures in race cars can far exceed normal and require a higher oil grade.
I'd look at several different multigrades in the 5W-40 range. Mobil 1 is notorious for oil consumption which indicates to me there will be brands/formulations that have more oil control than average.
A catch can is dirt simple to add and will isolate breathers as an issue. There are some dual cans which will further pinpoint where the oil comes from. Won't be any in the cans, though, it if's going out the exhaust via the rings.
-- Chuck
09-28-2017, 06:43 AM
#12
Yup - probably a late-model S2000!
Lovegroova was pretty much in the same place mileage-wise when his engine let go. That's what he ended up doing.
Unless you have a penchant for Lotuses, or something...
Lovegroova was pretty much in the same place mileage-wise when his engine let go. That's what he ended up doing.
Unless you have a penchant for Lotuses, or something...
09-28-2017, 06:44 AM
#13
UK Moderator
10-31-2017, 05:58 AM
#15
Thread Starter
Just an update for those interested.
Compression and leak tests came back fine. 200+ across all four cylinders, and under 20% for the leak (mostly being around <15%) I believe.
I've run a tub of Slick 50 Engine Treatment through that is supposed to help 'clean' the engine and imbue it, along with some RedEx in case valves are dirty or what-not (no doubt both snake oil I'm sure), but consumption is still up at around the 500-600 mark.
I haven't yet changed to any thicker oil as I have about 3 ltrs of the Castrol left in the boot, so am keeping on top at the moment.
What would be peoples next steps? Worth getting valve seals done? TGM doesn't think it would be worth it, as much like Nick said, if you're doing that, may as well have everything out to check it's all ok.
Compression and leak tests came back fine. 200+ across all four cylinders, and under 20% for the leak (mostly being around <15%) I believe.
I've run a tub of Slick 50 Engine Treatment through that is supposed to help 'clean' the engine and imbue it, along with some RedEx in case valves are dirty or what-not (no doubt both snake oil I'm sure), but consumption is still up at around the 500-600 mark.
I haven't yet changed to any thicker oil as I have about 3 ltrs of the Castrol left in the boot, so am keeping on top at the moment.
What would be peoples next steps? Worth getting valve seals done? TGM doesn't think it would be worth it, as much like Nick said, if you're doing that, may as well have everything out to check it's all ok.
10-31-2017, 08:43 AM
#16
Maybe fit a catch can to see if it helps blowby
10-31-2017, 10:03 AM
#17
My previous S2000 suffered from the same high oil consumption, it was an 02MY with 133k miles on the clock, it was using about a litre of oil every 400-500 miles and even more on the track. I carried out the following:
Cylinder leakage and compression test carried out and both came back with very good figures.
Stem seals changed which made no difference.
Catch tank which caught no oil whatsoever proving that it was not breathing heavily.
Changed from 5w40 Castrol to 10w60 Mobil One - oil consumption remained the same.
The conclusion is that the oil control rings were worn, many people would argue that if this were the case then the leakage and compression tests would show this however from experience working on engines oil consumption past the rings is dynamic problem and can't be found using leakage and compression tests.
My advice would be to carry on using it and just have plenty of spare oil!
Cylinder leakage and compression test carried out and both came back with very good figures.
Stem seals changed which made no difference.
Catch tank which caught no oil whatsoever proving that it was not breathing heavily.
Changed from 5w40 Castrol to 10w60 Mobil One - oil consumption remained the same.
The conclusion is that the oil control rings were worn, many people would argue that if this were the case then the leakage and compression tests would show this however from experience working on engines oil consumption past the rings is dynamic problem and can't be found using leakage and compression tests.
My advice would be to carry on using it and just have plenty of spare oil!
10-31-2017, 01:31 PM
#18
My previous S2000 suffered from the same high oil consumption, it was an 02MY with 133k miles on the clock, it was using about a litre of oil every 400-500 miles and even more on the track. I carried out the following:
Cylinder leakage and compression test carried out and both came back with very good figures.
Stem seals changed which made no difference.
Catch tank which caught no oil whatsoever proving that it was not breathing heavily.
Changed from 5w40 Castrol to 10w60 Mobil One - oil consumption remained the same.
The conclusion is that the oil control rings were worn, many people would argue that if this were the case then the leakage and compression tests would show this however from experience working on engines oil consumption past the rings is dynamic problem and can't be found using leakage and compression tests.
My advice would be to carry on using it and just have plenty of spare oil!
Cylinder leakage and compression test carried out and both came back with very good figures.
Stem seals changed which made no difference.
Catch tank which caught no oil whatsoever proving that it was not breathing heavily.
Changed from 5w40 Castrol to 10w60 Mobil One - oil consumption remained the same.
The conclusion is that the oil control rings were worn, many people would argue that if this were the case then the leakage and compression tests would show this however from experience working on engines oil consumption past the rings is dynamic problem and can't be found using leakage and compression tests.
My advice would be to carry on using it and just have plenty of spare oil!
This is on the nail Robin,,compression and leak down test only check the effectiveness of the compression rings, head gasket and valve seats, there is no way to check how good the oil control rings and valve stem seals except through visual checks, when i stripped Toms engine that had done 120+, apart from the failure i checked all the components against Honda service limits and the only things that were outside tolerance were the oil control rings to the extent that they fell through the bore without any resistance, and Toms engine burned copious amounts of oil but made good power on the dyno
11-01-2017, 03:18 AM
#20
UK Moderator