|12/08/2003 11:04:08||helen||hi guys , ive got an oil fountain!!! not been out in my saab for a couple of days, started her up and the oil filter was under so much presure that it burst its seal that joins the filter body to the treaded neck, Ive never seen this happen before. Any idea whats happened to cause such pressure build up, or was it simply the heat expansion, scared the bejesus out of me when it went.... any ideas?
|13/08/2003 01:18:41||Paul||So long as it doesn't happen again, i'd put it down to the unusual weather we've been having for the time of year.
I filled up my petrol tank the other day before driving home and leaving the car on the driveway. I came out a couple of hours later to see a steadily dripping stream of petrol appearing from under my rear wing (the filler pipe breather). The car must have got so hot sitting in the sunshine and the petrol expanded to such an extent that it was coming all the way up the filler pipe and out at the very top.
Didn't have any problems with the oil myself, though i did notice that i was leaving a slightly larger slick on the driveway when the weather was hotter (i figure that the oil is hotter, expands and so is thinner and has less trouble finding it's way out).
Have you changed the filter recently? Could be the seal was not quite sitting right. If you haven't, is it a genuine SAAB filter? The pressure reflief valve in the filter could be jamming or blocked.
Personally for peace of mind and about £3 I would put a new filter on it and just top the oil up afterwards but do use a SAAB filter.
|13/08/2003 08:53:49||Alec||P.S. Paul - don't you sleep at night?|
A lot depends on whether this happened at start-up or when hot/at higher revs. I can't think of any reason for this apart from failure of the filter due to excessive temperature (but the high ambient temps we are getting at the mo will still be much lower than a hot engine and it would have to f. hot to cause such a failure), a genuinely duff/blocked filter as Alec suggests (though why not happened before) or excessive oil pressure.
I've just checked, the pressure relief valve on the oil pump is supposed to open at about 50psi and I don't recall the car I had with an oil pressure gauge reaching that pressure at tickover, but it soon did from about 12-1500 rpm and up to a max of about 80psi - it had a stronger spring to increase the oil pressure. The standard filters survived this pressure easily. If the problem occurred on start-up then I doubt you've anything major mechanically to worry about, if it happened at higher revs then there is a possibility that the pressure relief valve is stuck shut, causing the oil pressure to rise too high, which would be a pain to sort - engine out etc. Don't know the physics but it's reasonable to guess that pressure will rise proportionally to engine/pump speed up to a point.
Hopefully the previous advice about fitting a new filter will sort it.
|14/08/2003 11:03:38||helen||thanks Guys, Invaluble advise as usual, will buy a new 'none' saab filter and refill . hopefully this will stop green peace protesting at the exon valdese style polution ive been causing down my street....
|21/08/2003 12:56:18||Richard||Saab one are £2.50 from Europarts|