Oil Pressure problems

[mikejb993]

My 993 had its annual service (6000 this time) a few weeks ago at a highly regarded independant dealer. I only do 5k miles a year and its been there before. Before the car went in, my oil pressure gauge showed 2 at tickover when fully warmed up, and moved up to 5 when the revs are 3500+. After the oil change/service, at tickover the oil pressure gauge now reads just over the 1 mark, and it still goes to 5 in the way it did before when the revs increase. My problem is that if I am in a trafic jam, and the oil temp obviously increases in the normal way, but not above the second white line, the pressure gauge shows just under 1 causing the oil pressure warning light to come on for about 7 seconds before going off again, and it never did this before the service, and this worries me. The oil cooling fan only works in the second stage, so this needs fixing but shouldn't be a big issue. I have checked the oil level and thats OK.

Being not very mechanical, I would be pleased to hear of ideas or thoughts about what may be causing this change, should I be concerned, and what I should do. Incidently, as regards oil type, they used 12 litres of TXT according to my invoice. I also had new discs and pads all round for a whopping £1400 bill!

 

[TRW40]

Mike

Sadly I am not too mechanical either. When I bought my 993 I noticed that the pressure dropped below 2 (but not as far as 1) on tickover. I was concerned because the guidance said it should be 2 to 2.5. Clearly the oil viscosity and oil level have a bearing on the pressure and so a change in either of these will be reflected on the gauge. However, I think you should consult your dealer about a drop to 1.

Tim

 

[38F3E1]

Mike.

Some of my thoughts on your post

1. A decent service (say 24K or 48K) plus new disks and pads all round will be about £1400 so I think the price you have been charged is reasonable. Seems in line with independents I use.

2.You need to find out what oil was in the car previously and what is in it now. If the viscosities have changed then that could explain the difference. I don't know how long you have had the car but if this is your first oil change it may have had a thicker oil in previously to 'mask' the problem you are now seeing.

3. Don't dismiss the effect of the cooling fan not working in the primary stage. The effect of this is that your car will get hotter when in traffic because it the temp will continue to rise until the secondary stage of the fan cuts in.

4. Ask the independent to explain the difference. If they are reputable then they will be willing to talk about your problem and work to finding a solution. I know that I would pick up the phone to my independent in a similar situation and we would find the problem. Perhaps drive the car over and get them to have a quick look over the car to make sure everything was done correctly on the service.

Ian.

 

[mikejb993]

Thanks for reply Ian

In answer to 1. It was a 6000 service at £210, discs and pads front £350, Pads only rear £108, Caliper plates £160, Disc realignment £40, so not new rear discs but refurbing the existing, plus lots of other small bits like new DME relay, Sensor Pads, Brake lines, and a new bosch battery @£89, all plusVAT. I expected a bill around £1000 - £1100, so was suprised at £1400. Seemed expensive. Got me wondering what an OPC would have cost.

2. My invoice from last year, same dealer, shows the same TXT oil used for a 24k service at £435

3 & 4. I did drive back, which highlighted the fan problem, and I will get this fixed sooner now following your comments, and talk to them a in a bit more detail.

By the way, it was JZ. I'm a little disappointed, for example, minor thing, but was charged last year for new wiper blades, done 5500 miles and was told I needed new wiper blades again this year? There reputation is second to none, so its hard for me to think that they have given me anything but first class service.

 

[mikejb993]

Hi Maurice, thanks for replying

Car is '96 carrera 2, done 81,000 miles now, and runs and sounds very good. No Oil drips, or problems at all mechanically.

According to my service record, the TXT oil was the same as they put in for my 24k service at this time last year, at which time I had new rotor, dist cap and belts etc, which I do believe to be genuine. This time around it was just a 6k service, and I noticed the change in tickover oil pressure reading straight away, but cannot think what would cause it.

JZ Machtech, who are highly touted on this forum for good service, have been looking after my car since I got it 2 years ago.

 

[mikejb993]

Hi TRW40

It does sound quite unanimous that I should use fully synthetic as opposed to the semi. Thanks for reply.

 

[TRW40]

Mike

How are you getting on with your oil pressure?. Having proudly stated that I have not got close to 1 with my pressure before, my car did just that on Friday. I had left the car for about 10 minutes and when I returned the engine fan was running. I jumped in, started her up and noticed that the oil was hotter than normal (about half way up the gauge). On tickover, the pressure dropped to nearly 1 but the pressure was fine when revved. The only difference I could think of was that the day was really hot and I had been using the A/C on full blast. The car was fine again yesterday so I am a little confused! You mention that the cooling fan should operate in two stages. Perhaps you could let me know how you find out whether both stages are working?
Many thanks
Tim

 

[TRW40]

Cheers Maurice - I will have a look. Where would we be without you.

Tim

 

[mikejb993]

Thanks for asking TRW40, the car is booked in next week to have the oil cooler resister fixed so that the first stage of cooling works again, and for a general check over.
At JZ, they plugged in some kind of diagnostic computer thingy/meter and simulate the conditions for the 2 stages of the fan, and it showed the first stage not functioning, which is apparently quite common.
I have driven the car many times recently without any problems, but its not been quite so hot lately, and I've not been in any serious traffic jams. As you have discovered, with hot conditions and AC on, this contributes to hotter oil and consequently lower pressure, but I would prefer not to see the warning light! It was mentioned also that it could be a faulty gauge or possibly the cars tickover revs too low, but that I shouldn't worry too much as she still moves up to 5 when the revs are increased. So we'll see next week

 

[Shane Hodges]

Mike, Can I ask what oil you use for topping up given that TXT is a workshop oil only.

I had my car serviced at JZ for the first time a few months ago and it was disappointing to read Maurice's comments as to why a garage might use this oil!

Maurice/ Oilman, I've just had a chat with JZ re what to use for topping up, and they said that the TXT is fully synthetic - I pushed twice to confirm, and they definitely said Fully Synthetic 5W-40. Interesting eh.

So to top up ... I have some Fully Synthetic Mobil 1 (0W 40) and some Semi Synthetic Esso Ultra (10W 40) sat in the garage ...... recommendations and views much appreciated.

Thanks in advance.

 

[Guest]

I was told by the mechanic where I bought my car (indi specialist) that it's okay to top up with semi-synthetic if the bulk of the oil is fully synthetic or vice versa. He mentioned that although the two oils may separate in the tank they'll mix without problem once the engine is running.

He also recommended that I used a semi-synthetic oil as the fully synthetics oils can damage the seals if the car isn't used that much.

From what I've read on the this forum I'm starting to think that I'll stick with Mobil 1. Is there any truth is this issue of fully synthetic oils damaging the seals ?

 

[bones]

Darren read our oil experts answer to your question on hypothetical seal damage caused by using synthetic oils in the Technical Articles forum.
http://www.porscheclubgbforum.com/default.asp?forumid=100

 

[Guest]

Many thanks for that Bones. Here's the quote from oilman if anyone else is interested "This is a myth, use a good PAO/Ester syntehtic and you will have not problems, this myth is caused by using a synthetic that is too thin. "

So I think I'll stick with Mobil 1 (PAO) or Silkolene PRO S 5w-40 (PAO/Ester) - though I'm not due an oil change/service until April 2006. Looking back through old invoices I got with the car I can see that it currently has Castrol 5W-40 fully-synthetic slushing about inside it []

 

[mikejb993]

I have Mobil 1 also as my top-up oil, as its been recommended before.

I have had the oil cooler resistor rectified so that the first stage now operates and this seem to have cured the problem, although as I drive now, I seem to be looking at my oil temperature gauge more often than the rear view mirror these days!

My squeeky windscreen was also cured at the same time, screen beading that JZ Mach suggested seems to have done the trick. (for now).

I asked Steve (one of the partners) at JZ about the Fabspeed maxflo exhaust that I liked the sound of when I heard it at Le mans, and his opinion is that I would like it for about a month and then I would want it taken off again due to the resonance when I'm cruising along at about 3000 revs. It would get on my nerves he said. Reckons he's taken many off. Any other opinions on this?

 

[968er]

I have the maxflo's on my car and would not replace them. They give the car a much better sound which still makes me have the window down and listen to the growl.

People that seem to want rid of them are looking for a quiet ride, so they should go and buy a BMW!

 

[LK_991GTS]

ORIGINAL: 968er

I have the maxflo's on my car and would not replace them. They give the car a much better sound which still makes me have the window down and listen to the growl.

People that seem to want rid of them are looking for a quiet ride, so they should go and buy a BMW!

I understand from a number of sources that it's the resonance with the maxflos that is a significant problem for people, not necessarily simply the volume. Do you notice any resonance?

 

[968er]

I find that there is a little resonance around 2000 revs, but nothing up around the 3000 rev mark.