What causes a drop in engine oil pressure?

Thursday January 3 2019

Toyota Hilux Surf

Toyota Hilux Surf 

By Paul Kaganzi

Hello Paul, I have just gone through an engine overhaul of my 1994 Toyota Hilux Surf after realising loss of power which was attributed to worn out piston rings. However, now the engine oil pressure which reads within the normal range at idle, drops when the engine gets hotter. Actually dropping to near zero. The turbo is also known to be worn out, but we are still pooling resources to fix that. What might cause the drop in oil pressure?

Hello, it is not unusual to have low engine oil pressure when you start a cold engine. Ordinarily, within 15-20 minutes, a normal engine should have built sufficient oil pressure as it warms up.
This should be confirmed by the oil pressure gauge resting at the midpoint. In the event that the oil pressure drops as the engine warms up, you need to pay attention to the oil pump and pressure relief valve.
The oil pressure pump plays a crucial role in the regulating of engine oil pressure. If engine oil pressure pump fails, it will not be able to build sufficient oil pressure. Your mechanic will also need to check the oil pressure relief valve.
This valve regulates engine oil pressure depending on the flow rate. Engine oil filters have oil pressure relief valves which will allow engine oil to continue blowing in unique circumstances such as when the oil filter is clogged with aged oil.
This can lead to oil pressure dropping as the engine warms up. Other causes of low engine oil pressure are worn-out crankshaft and bearings.

Toyota Raum and Sienta: Which is better?

Hello Paul, I am indifferent about buying a 2006 Toyota Raum and a Toyota Sienta. Please advise me about both cars.

Hello, the 2006 Toyota Raum and Toyota Sienta both have a fuel efficient 1.5 litre 1NZ-FE 16 valve DOHC petrol engine. The Raum is spacious enough for a family of four but the Sienta is much more spacious because it is longer, wider and has a higher roof.
Passengers in the Sienta will have better leg-room, shoulder-room as well as head room. On the other hand, the Sienta’s cube shaped body is not as aero dynamic as the Raum.
This should have an impact on fuel economy however, the CVT (Continous Velocity Transmission) gearbox on the Sienta mitigates that problem by creating a fuel efficient mating of the transmission and engine.
So, be adventurous and fear not the spacious cuboid shape of the Sienta which feels like driving a Royal carriage. You may have a little difficulty finding the costly head and tail lights of the Sienta when you get bumped into by a boda boda.

Help me choose between a Premio, Brevis and Progress


Hello Paul, I need to make a choice so I need your advice. I love comfort, speed and safety. What car would be best between a Toyota Premio, Brevis and Progress? Kevin.

Hello Kevin, your car choice ought to be between the 2006 two mid-sized luxury sedans - Toyota Brevis and Toyota Camry. The Toyota Premio is a smaller compact sedan with smaller engines and seating room, so it does not seat well with your specs for comfort, speed and safety. Brevis and Progress suit your buying needs. For starters they both share the popular 2.5 litre petrol 1JZFSE engine which delivers an exciting power output of 147 KW (197HP) @ 6,000 rpm.
This is enough to give you some reasonable ‘muscle’ to put up a highway sprint without emptying your fuel wallet. The double wishbone lower suspension, macpherson struts give both cars good handling on the highway. Safety is bolstered by twin airbags, anti-lock brakes (ABS), Vehicle Stability Control (VSC) and radar cruise option to detect approaching vehicles ahead. Styling cues of the Brevis have smooth well rounded edges with beautifully moulded lights complemented by its slightly bigger dimensions LXWXH (4550 X 1720 X 1460) give it an edge over the progress in comfort and handling terms.
The smaller Progres (4500 X 1700 X 1435) styling is not helped much by the bead-like headlights. Both the Braves and Progres have excellent comfort. Passenger seating space is slightly better in the bigger Brevis. Audio entertainment, walnut wood impressions, Air conditioning, power adjustable seats and mirrors. In the tight contest Progres will play second fiddle to the Brevis.