BRoomers,
I'm currently looking at a (petrol) turbo.
Whilst we know simmering is a good idea in the right circumstances, is it possible to tell whether it's been simmered by the previous owner?
Stu.
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Perhaps a passing moderator will be kind enough to kick this into technical...if only out of sympathy.
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brill
the answer is no. YOur only way of knowing how well the turbo has been treated is by finding out if the oil has been changed regularly, and listening for any noises. The turbo on my cav 1.7td was well on the way to being kippered (at 56k miles). Could tell cos it made a kinda squeeling/whistling sound when cold.
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Perhaps a passing moderator will be kind enough to kick this into technical...if only out of sympathy.
Oh, ok then. Seeing as you asked nicely ;o)
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Stu,
Agree with RF, lack of simmering after hard use cokes up oil on the bearing surfaces, so other than a failed or very noisy turbo, dismantling and inspection would be the only way to go.
Now this may not be correct, but I seem to remember that some turbos are water cooled and that the simmering is not so important, anyone else confirm this?
Ian L.
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Yes you're right Ian.
Some Renaults, for example, are water cooled and they even have an aux electric water pump that runs on a timer for many minutes after you stop the engine.
Some folks never work out what that odd whine is! Also the timer-relay can fault so the pump runs for so long after you turn off the ign the battery goes flat all the while.
M.M
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You can check the bearings on some turbos. It depends on accessibility.
Health warning - ONLY DO THIS WHEN THE ENGINE IS COMPLETELY COLD, otherwise you will end up with fried fingers.
Its been a few years since I did this on my nissan 200sx.
You will need to undo the clip which holds the induction (inlet) pipe on. Remove this and you may be able to see or at least feel the turbo. Hold the fins and see if there is any play in the spindle either side to side or in/out. There should be some movement of a couple of mm, but no more than that. If there is excessive play then the bearings could well be on the way out.
You could also check for oil in the inlet pipe. There will be some oil there normally, but you should clean it out and check say a week later, or after a long drive to see how much oil is being drawn through the crankshaft breather system or from the bearings. If it is excessive, you should consider some repairs before it fails.
Sorry its not very technical, but I do remember doing this, when I had an old turbo on and again after when I had a recon one, there was a difference between the two.
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If you can feel a couple of mil play then the turbo is knackered. You should not be able to feel any more than the very slightest lateral movement of the shaft and just a little sideways movement.
A reasonable indicator that the car internals are clean might be to remove one of the cam covers and inspect inside. i did this on my Rover turbo and found it to be spotless, so hope that the turbo bearings are similarly clean.
Have a look at some info I posted on this thread too:
www.honestjohn.co.uk/forum/post/index.htm?f=4&t=59...8
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