rattle from engine - oil test (for metals) needed ASAP
Discussion
Hi guys, im going nuts here trying to figure out the source of a noise on my rev3 MR2 turbo (3S-GTE). Engine has just finished being refreshed (all pumps, hoses refreshed, new turbo, new fuel system, new EMS).
There is a rattling sound, like a nut being shaken in a can when the engine runs.
This is usually pretty diagnosable as its either:
- bearings being chewed due to big end failure (BAD)
- something loose like a heatshield, bracket etc
- a crack in the exhaust manifold
- a loose bolt in the aux belt system
- something physical moving around inside the engine itself
- something inside the turbo
- something in the tranny (clutch release bearing etc)
- driveshaft bearing
but its NOT ANY OF THESE DAMN THINGS! (or at least not obviously).
short of running the engine on a bench, i've tried to isolate everything going without success. The oil in the sump is clean (like brand new clean). No marks, scoring or wear on the big end bearings, main bearings, or crank - looked at by dropping the sump + boroscope.
everything else has been stripped off the car, boroscope down to look at the valves and pistons etc. The only evidence of something wrong i can see is a TINY mark on #1 piston.
Turbo is clean and spins free. Clutch in / clutch out doesnt change the noise. Driveshafts disconnected, still noise.
Exhaust mani and turbo pipework is in great shape.
Headgasket is fine, no oil leaks anywhere.
All i can think of is I'm in early stages of big end failure & rattling bearings, but because oil was changed VERY recently, and before the car has been run for more than a few minutes, there hasnt been enough time for metal to be visible in the sump (although surely wear would be visible on the crank and bearings??).
So next step: Can anyone recommend an oil tester near London (I'm in West London, Hammersmith....car is in with a specialist in Luton)? I want to get a proper analysis for metal in the oil.
There is a rattling sound, like a nut being shaken in a can when the engine runs.
This is usually pretty diagnosable as its either:
- bearings being chewed due to big end failure (BAD)
- something loose like a heatshield, bracket etc
- a crack in the exhaust manifold
- a loose bolt in the aux belt system
- something physical moving around inside the engine itself
- something inside the turbo
- something in the tranny (clutch release bearing etc)
- driveshaft bearing
but its NOT ANY OF THESE DAMN THINGS! (or at least not obviously).
short of running the engine on a bench, i've tried to isolate everything going without success. The oil in the sump is clean (like brand new clean). No marks, scoring or wear on the big end bearings, main bearings, or crank - looked at by dropping the sump + boroscope.
everything else has been stripped off the car, boroscope down to look at the valves and pistons etc. The only evidence of something wrong i can see is a TINY mark on #1 piston.
Turbo is clean and spins free. Clutch in / clutch out doesnt change the noise. Driveshafts disconnected, still noise.
Exhaust mani and turbo pipework is in great shape.
Headgasket is fine, no oil leaks anywhere.
All i can think of is I'm in early stages of big end failure & rattling bearings, but because oil was changed VERY recently, and before the car has been run for more than a few minutes, there hasnt been enough time for metal to be visible in the sump (although surely wear would be visible on the crank and bearings??).
So next step: Can anyone recommend an oil tester near London (I'm in West London, Hammersmith....car is in with a specialist in Luton)? I want to get a proper analysis for metal in the oil.
Wadeski said:
There is a rattling sound, like a nut being shaken in a can when the engine runs.
In all seriousness, I've had Luke at Pacific Works and Nathan from Century Motorsport, who probably know more about MR2s than anyone else in the UK stumped - so I'm turning to the PH masses out of frustration!
both hot and cold.
engine hasn't been opened, so shouldnt be piston slap (common on forgies).
injectors, fuel pump, turbo have been upgraded. water pump, oil pump, thermostat, all refreshed with stock parts.
boroscope shows nothing dodgy in the valvetrain, and the noise is hard to pinpoint with a scredriver in ear - it doesnt seem to be coming from one obvious place, as top-end clatter would.
engine hasn't been opened, so shouldnt be piston slap (common on forgies).
injectors, fuel pump, turbo have been upgraded. water pump, oil pump, thermostat, all refreshed with stock parts.
boroscope shows nothing dodgy in the valvetrain, and the noise is hard to pinpoint with a scredriver in ear - it doesnt seem to be coming from one obvious place, as top-end clatter would.
Some injectors can be extremely noisy in normal operation!
ETA Don't want to be alarmist but someone dropped a nut when rebuilding a BMW 323 engine for me once, we searched everywhere and couldn't find it. It revealed itself the following day when it came out through the side of the water pump... It must've got bored of spinning round and round!
ETA Don't want to be alarmist but someone dropped a nut when rebuilding a BMW 323 engine for me once, we searched everywhere and couldn't find it. It revealed itself the following day when it came out through the side of the water pump... It must've got bored of spinning round and round!
Edited by Poledriver on Monday 22 March 23:29
Wadeski said:
My current theory is beginning of big end failure, masked by the very recent oil change, so no visible crud in the sump and nothing visible in the bottom end.
Is my idea of getting the oil tested for metal content daft then?
Not daft, but possibly difficult to find someone to do it and possibly expensive. To do the job properly they'll need a PMI tester to identify exactly what metals are present in the oil!Is my idea of getting the oil tested for metal content daft then?
What part of the country do you live in, there are a few companies who have PMI equipment.
I used to work for a company where I was responsible for supporting the PMI equipment. They are based in Milton Keynes and the manufacturers are in High Wycombe. I'll make a couple of calls tomorrow if you think it may help.
have you tried draining a little oil out to check for any solid/metallic residue?
have you tried draining a little oil out to check for any solid/metallic residue?
mate we've drained the sump and gone through with lights, filter, spreadng it out really thinly - it looks brand new, which is good because it is brand new oil.
sadly i dont have the old oil from when it was changed 4 weeks ago.
oh and thanks for looking into the PMI - might be a good test.
sadly i dont have the old oil from when it was changed 4 weeks ago.
oh and thanks for looking into the PMI - might be a good test.
Edited by Wadeski on Monday 22 March 23:53
fitted by the factory when the car was built! Car has not had a rebuild, just ancilliaries refreshed (pumps, belts etc).
my first thought was one of the new parts was dead (water pump or something) but car has been gone over with a process of elimination and it doesnt appear to be them.
my first thought was one of the new parts was dead (water pump or something) but car has been gone over with a process of elimination and it doesnt appear to be them.
Any rotating problems would rise with engine revs though.
Does it do it clutch engaged, disengaged ? in gear, out of gear ?
Have you tried a stethoscope ? Tried removing any drive belts to eliminate external rotating parts ?
Undoing injector's one at a time ?
Inspecting/holding various shielding etc
Does it do it clutch engaged, disengaged ? in gear, out of gear ?
Have you tried a stethoscope ? Tried removing any drive belts to eliminate external rotating parts ?
Undoing injector's one at a time ?
Inspecting/holding various shielding etc
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