Should I be worried?

[Stephen Edwin]

Originally Posted by capt jack

Thanks Dave. Yes, I'm going to change the oil every 5,000 come what may, and use a Mann filter. Previously the car had been serviced by Volvo, with every serviced from new recorded. But at just 89,000 when I bought it, that's only 4,500 per year, and I reckon it's probably suffered from under-use a bit. However, I'd like to keep it for a good long time, so a 5k interval with fully-synth 5w-30 is what it'll get from here on. I'll try the ATF trick too, although the top end doesn't really rattle at all now.

The other thing I've "cured" is the squeaky front suspension. A squirt of PTFE spray on the wishbone bushes, and on the ARB ones as well, seems to have sorted it. I'm going to get some poly bushes for the ARB though, as the originals certainly don't look to be in good shape. The bushes themselves are not available from Volvo, but there is a SuperFlex alternative listed. The car has a hefty 24mm ARB, the bushes for which look to be a special order from Superflex.

But it's a fabulous car!

Sadly I managed to clip the rear bumper on a low gate post, but I'm sorting it out myself. The damage is very low down on the OSR quarter of the bumper, and well within my rattle-can capabilities.

Last on the list for now is a possible LPG conversion. I was made redundant last month, so the luxury of a 6-mile commute has been lost. Am starting a new job tomorrow but it's 25 miles away, so the fuel bill is going to climb a bit. I had a p1 V70 on LPG for 10 years and 250,000 miles, and so I'm perfectly happy with doing the same to the S90. I might just include a top-end lube kit though. The V70 had the 10v engine and was very happy on LPG, but this 24v beastie might just do a bit better with the lube kit. We shall see.

Cheers

Jack

Good point re mileage and oil. With your higher mileage a 5k change makes sense. With a low mileage, e.g. my current less than 1k p.a., I change every six months. And a genuine Volvo filter.

I used to change plugs every 12 months. But that seems wasteful on low mileage. So I am going over instead to a deep clean every six months. I juse a grit blaster spark plug cleaner. Personal experience has taught me how effective that type of plug cleaner is.

And I have it mind to do an Italian Tune Up ....

[capt jack]

Well I thought that I'd cured the oil light issue, but it seems as though I both have and have not done so!

I'd noticed that since the oil and filter change, when started first thing in the morning, the oil light goes out at once, but if started after having been left for a few hours, the light still lingers a bit.

The only thing I could think of was that first thing in the morning the car is parked on the drive having been reversed into the space the night before, so the engine is basically ticking over for at most 30 seconds before being switched off. Through the day, on arrival at work I pull into the parking bay and switch off straight away.

So today I tried leaving the engine idling for 30 seconds or so after arriving at work.

And bingo! Upon start up this evening, the car having been parked all day, the light went out at once.

So it would appear that if the engine is allowed briefly to idle / run at low revs before switch off, at the next start up even hours later, the oil light will go straight out.

If however the engine isn't allowed to idle or run at low revs before switch off, then at the next cold start up the oil pressure light will linger for a couple of seconds.

I really am at a loss on this one. I know that if the engine is turbo-charged then a few seconds idling before switch off is a good preventative measure as it gives the turbo a chance to spool down and cool down. But how does this affect a non-turbo engine? We aren't talking about anything more than the fifteen or twenty seconds, thirty at the most, that it takes for me to pull up outside the house and then reverse park slowly the half-dozen yards into the driveway.

As a matter of routine, now I'm going to let the car idle for just a few seconds before switching off, but can anyone puzzle out just what is happening? Or is it most likely that simply I do indeed have a slightly dodgy oil pressure switch, that as with any failing electrical component, sometimes it works at once, sometimes it doesn't?

Any thoughts and theories gratefully received!

Cheers

Jack

PS: Rattle can repair completed on Sunday, and I'm really pleased with the result!

[Laird Scooby]

Have you added some ATF to the oil yet Jack? I'm wondering if the oil pressure relief valve spring is sticking due to the previous neglected oil/filter changes. I had this on a 740 with very similar symptoms and a duff oil pressure switch!
I renewed the oil pressure switch but still had the symptoms until i added some ATF, ran it for a few weeks then did an oil/filter change.

[Stephen Edwin]

Possible complete red herring, but. Does your oil filter have the valve to keep the oil system primed after switching off the engine, so that the engine has oil ready and waiting in position where it needs to be every time the engine is started?

[Laird Scooby]

Originally Posted by Stephen Edwin

Possible complete red herring, but. Does your oil filter have the valve to keep the oil system primed after switching off the engine, so that the engine has oil ready and waiting in position where it needs to be every time the engine is started?

Good thought but won't make any difference as the oil filter hangs down with the open end/mating face upwards to the block so can't drain back to the sump to give the problem you're suggesting Stevo.

If it was mounted "on its side" so the mating face was on the side of the block this would be a consideration as it would give the possibility of draining back to the sump, resulting in the need for it to be refilled before oil pressure was achieved on the next cold start.

That said, the filter is on its side on my 760 and i still don't have that problem. I did when the original filter was blocked though!

[capt jack]

Originally Posted by Stephen Edwin

Possible complete red herring, but. Does your oil filter have the valve to keep the oil system primed after switching off the engine, so that the engine has oil ready and waiting in position where it needs to be every time the engine is started?

Yes, it does! The oil filter is mounted horizontally at the very front of the engine block. Which made it a bit interesting to fill the new filter with oil before actually screwing it home! The oil filter is a Mann 917, and has a bypass valve and an anti-drain-back valve. The pressure sensor is right at the back of the engine, about as far away from the oil filter as it could be. There is some evidence of a small oil leak around the pressure switch, but it's very difficult to see, let alone actually get onto with a spanner or socket.

Peering inside the Mann filter as best I could, it does look different inside to the TJ filter that was there before.

The other thing that struck me is that the oil filter mounting looks much newer than the rest of the engine block - it's shiny and clean, whereas the rest of the engine block looks like 20-yr-old aluminium alloy. I could well believe that the mounting is not original.

My present theory is that the pressure switch is a bit tired, and therefore slow to react. Its connecting wire looks less than perfect, and the whole area is dirty. The wire is also not tight in the terminal block on the switch. If I switch the engine off while it's still cold and then turn the ignition on again, the oil light takes a good 15 seconds to come back on. Add to that the fact that the switch is at the opposite end of the engine from the oil pump and filter, and quite a bit above the level of the filter, then everything is against the switch being able to respond quickly.

Fitting a better quality filter and oil has helped to overcome to a degree, but the switch itself is still tired, and under some circumstances it will always be a bit lazy.

There's no top end rattle, the car runs smoothly and quietly, and I'm trying to convince myself that there's nothing to worry about!

Cheers

Jack

[Laird Scooby]

Your filter isn't mounted like this then Jack?



Oil filter is tricky to see right down at the bottom of the pic.

[Stephen Edwin]

That's interesting Jack and David. And. I begin to understand a bit more now why my oil filter has the valve in it!

[Stephen Edwin]

Originally Posted by capt jack

Yes, it does! The oil filter is mounted horizontally at the very front of the engine block. Which made it a bit interesting to fill the new filter with oil before actually screwing it home! The oil filter is a Mann 917, and has a bypass valve and an anti-drain-back valve. The pressure sensor is right at the back of the engine, about as far away from the oil filter as it could be. There is some evidence of a small oil leak around the pressure switch, but it's very difficult to see, let alone actually get onto with a spanner or socket.

Peering inside the Mann filter as best I could, it does look different inside to the TJ filter that was there before.

The other thing that struck me is that the oil filter mounting looks much newer than the rest of the engine block - it's shiny and clean, whereas the rest of the engine block looks like 20-yr-old aluminium alloy. I could well believe that the mounting is not original.

My present theory is that the pressure switch is a bit tired, and therefore slow to react. Its connecting wire looks less than perfect, and the whole area is dirty. The wire is also not tight in the terminal block on the switch. If I switch the engine off while it's still cold and then turn the ignition on again, the oil light takes a good 15 seconds to come back on. Add to that the fact that the switch is at the opposite end of the engine from the oil pump and filter, and quite a bit above the level of the filter, then everything is against the switch being able to respond quickly.

Fitting a better quality filter and oil has helped to overcome to a degree, but the switch itself is still tired, and under some circumstances it will always be a bit lazy.

There's no top end rattle, the car runs smoothly and quietly, and I'm trying to convince myself that there's nothing to worry about!

Cheers

Jack

I appreciate you have fitted a better quality filter. But. Is it possible that your oil filter with the valve, is ether not truly best quality, and/or is one that missed quality control in production.

[capt jack]

Nope, the oil filter on my beastie is mounted at 90 degrees to the vertical, just about in the place that there appears to be some sort of blanking plate next to the filter in Dave's picture.

I'm wondering if it's had some sort of mod at some time? In which case, I wonder why?

The Mann filter that I've fitted is I believe about as good quality as it gets, and it definitely does have the anti-drain back valve fitted. Or at least the spec sheet on the Mann website says so.

I tempted now to go into a Volvo main dealer and see what they say!

The car has been stood overnight and most of today, and when I went out to start the engine this afternoon the oil went straight out as soon as then engine fired.

I love this stuff. It is what makes this forum so good!

Cheers

Jack