Questions and Answers

VW Oil Pressure Q. Had two of these vehicles. One an automatic, the other a 5-speed (parts car). Daughter's 16th birthday car this year. Anyway she cooked the engine in the automatic, switched the engines, Standard transmission engine to automatic and switched transmissions, all went well---except after hooking up all the wires I labeled, back to their terminals.

The oil pressure idiot light blinks (up until 3,000 rpm) and once I start the car the oil pressure gauge pegs out. Gauge was working on old engine. To date I have switched the oil pressure sender from original engine was working OK, checked both ground straps, switched wires on two posts out of sending unit. Haven't put a true mechanical pressure gauge on engine.

Question is; do you think I have an electrical problem, sending unit problem or worse yet an oil pump problem or none of the above? Also, temperature gauge doesn't work nor temperature fan switch, haven't got into that yet, could they be related?

1987 VW Cabriolet
1.8 liter
Automatic

Have triple checked and did hook up wires as labeled, checked fuses and relays for both.

Thank you

A. Without a mechanical oil pressure reading the actual oil pressure, it would be difficult to determine where the problem lies. If one car had a gauge and the other an idiot light, then the Oil Pressure Switch (OPS) is the problem. The OPS are different for light and gauge. That would be the only thing that can be determined without a mechanical reading.

Another possibility is that each engine had a different OPS. You need to look at the color of the OPS to see if they are the same. One is a 0.3 bar switch (brown) and the other is a 1.8 bar switch (white).

I think the problem lies with the OPS more than the actual oil pressure, unless it became a parts car due to engine problems.

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