Club 80-90 Forums

Hello,

I want to install an oil pressure gauge on my tdi. When I brake the oil light flickers and I'm worried the pump might be not functioning to its full abilities. The bod circuitry connected to the 0.9 bar switch above the oil filter all works and has never gone off, so it's the 0.3 bar switch on the cylinder head that's triggering it. I know that I'm using the right oil, and there's enough of it, so it's not a viscosity problem or that I'm running low. It stops flashing when the car's stopped and is just idling, but it's happening too often for my liking. It's possible it's the 0.3 bar switch itself of course.

My question is - for a tdi, should I be connecting an oil pressure gauge sender to the 0.3 bar switch, or to the one above the filter and pump? If so is there a sender/gauge someone can recommend with both connections on it or should I get a t-splitter? I'd much rather find one which could double as a 0.3 bar switch for the warning light to, since that's where the low oil pressure is being triggered from.

Thanks a lot indeed as always for any advice. I had a look through the forums and wiki and found useful stuff, but it seems the oil pressure switches on the tdi are in different places than on a jx.

Ewen

Good point Ewen. I've thought about this, intending to fit gauges and an oil cooler when I get a 'roundtooit'. Engine design prioritizes oil supply to the most stressed bits first; crank bearings, big ends etc. therefore failure in oil pressure/supply usually lunches these bits first. So the pressure that you want to monitor primarily is the output from the pump, so I'd take the gauge feed from the tapping on the pump/filter. I would be careful about a T-connection between the head tapping and the pump/filter tapping - you would be introducing an 'oil gallery' that the engine designers hadn't bargained for, possibly depriving some other area of sufficient pressure. Of course, this is only my opinion......

Hello Wolfsburg Willy,

I appreciate the advice and the opinion. According to some sources when the engine's hot you can tell the pressure at any point so I might first have a go with the cylinder head since that's where the low pressure signal's coming from. I'll change it if it turns out the switch is reading right, and place it in the high pressure switch tapping. Certainly not thinking of putting a t-piece to connect the two tappings together! Will let you know the results....

Ewen