N75 and Oil Pressure

[davidmcluckie]

I've been doing a lot of searching and reading and am posting this just to make sure with you guys I haven't missed anything.

When I got my car I knew it felt under powered but had read about the N75 valve being a fairly common thing to go wrong and causing this.

I have Vag-Com from my previous days driving a Fabia vRS and it flagged the N75. So I set about removing the N75 when the end of the plug fell off whilst removing. That'll be the problem then. Checking the resistance of the N75 and it showed 31ohm, so within spec. Made 2 new connections onto the N75 and cleared the code.

Took it out for a spin, went like a new car.

After a few minutes the red beeping oil pressure light came on. Pulled over, checked oil was ok. Restarted and light was out. Driving back to the unit light came on again so I pulled over again. Light goes back out. Made it back to the unit driving gently and light stays off. Disconnecting N75 and driving and the light stays off.

I am right in thinking I will have the 'sludge' problem? So when the turbo kicks in, the sudden load causes the oil pressure to drop low enough to trip the sensor? When the N75 is unplugged it can only increase load gradually still maintaining enough oil pressure.


My plan is to remove sump and clean/replace the oil pickup pipe/gauze. Is there anything else I should be doing while I'm in there. It'll all be getting done on ramps as thankfully my dad and friends are mechanics.

[steveheather]

Hi there. I presume that you are talking about the 1.8t powerplant here. Irrespective of whether the 'sludge' issue is at the root of your present problem (and I would suggest that it very likely is), I would take the action that you are proposing anyway. It is a must for this particular engine application. It has been recommended to me as a routine preventative maintenance measure every 60k to 70k miles and I have seen no convincing reason not to follow the advice.

I had the sump off of mine last year and a new oil strainer fitted at 'Crashers' place in Nottingham. After 65k the gauze was about 50% blocked with carbon debris. The sump pan was in a mess and was thoroughly cleaned with Nitromors paint stripper.
The following day, I whipped the camcover off and thoroughly cleaned all the nasty burned on oil deposits from it using Nitromors. It took three or four applications to completely clean it back to metal and I then made sure that all the chemical as cleaned away before reassembly. I would suggest that you also do this and then follow it with regular annual oil changes, making sure that you use the large spec oil filter which boosts the amount of oil that is carried in the sump/filter.

Best of luck, Steve

[davidmcluckie]

It is indeed the 1.8T and I thank you for your reply. My engine has done a little over 100000 and I don't think it has been cleaned by any of the previous owners.

To round things off the exhaust snapped at the flexi pipe. When it rains it pours.