If you had an engine that required new liners, I doubt fitting new bearing shells would be much good. Come to that, fitting new bearing shells only is a waste of time - unless the old ones are unworn. The crank wears too...
The oil doesn't actually damage the wire. The wire is perfectly OK, underneath its slightly insulating coating of oil. Even if the oil isn't insulating, and is actually conducting heat, this is still a problem.
The way that this type of MAF works is to have a heated wire of known characteristics. The greater the airflow, the greater the wire cools down. The engine can measure this cooling (probably by using a constant current source, and measuring the voltage, or a constant voltage and measuring the current).
When oil, or any contamination is on the wire, its characteristics change, which means that the engine can no longer accurately measure the airflow, leading to incorrect fuelling.
Pete.
That's absolutely right, and happens regardless of filter type, as well. I clean mine about once a year, the reading tends to decrease from around 2 pounds of air a minute (when good and dirty) to 1.5 pounds a minute, given similar engine / air temperature and revving at about 3000. There's little difference at tickover, but then that's probably not too surprising as the MAF must be ideally suited to a given airflow range, on a road car somewhere around the maximum torque (so as to enhance mpg instead of restricting peak power).
So far, whatever detritus has stuck to the MAF wires has come off with a squirt of injector cleaning spray - I guess this is tantamount to brushing in a petrol bath, and so I still think this means the MAF will not be damaged by oil contamination by the filter.
Unless someone can propose a mechanism where it can be damaged?
It's not the case. You only get a heap of oil coming off the filter, if you have too much on it :)
Everyday!!
Cleaning is not standard service procedure, therefore if contaminated it is damaged and is replaced.
Had a run in with a 'professional mechanic' earlier this year, he was proud that he had done a good job fixing many cars by replacing the MAF and fitting a genuine air filter to prevent lint contamination. He had never attempted to clean one, the thought that he could do so and save his customers money had never entered his head. Even after it had been suggested he held fast to the fact that cleaning the MAF was not in the makers service book.
I doubt he would parcel up the electronic contents of his scrap bin and send it me for re-con.
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That's amazing, when they cost a hundred quid, cleaning can take 30 seconds and seems to be a completely effective restoration.
Ouch! Why would anyone go to a garage where that was going to happen?
"New windscreen, sir, the old one had dead insects on it. And we've replaced the back seat, it had an old coffee stain."
It's the sort of thing that you'd want, though eh? Quick clean of the wires, test the readings and sell them on ebay at half the retail price, onto a winner there and no mistake.
looks like I have successfully started a massive thread
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