Astra Oil Light Delay - Mobile Office

Thanks to everybody for the feedback on my previous problem.

On the same 2000 Astra 1.7DTi (isuzu) with 42k miles of which I have owned for about a month, I have noticed that when starting from cold (and also from warm when standing for minimum of approx an hour) the oil pressure warning light takes a good 5 seconds to estinquish. I have changed oil filter and put some decent Magnatec GTD oil in her, as it never hurts to do so, but alas same characteristic.

It never comes on whilst driving and I do know she is slightly over-filled. Apparently an easy mistake to make with the 16v's.

As this is my first diesel, am I looking at a normal characteristic, or should I be worried?
Astra Oil Light Delay - HF
Far be it for me to believe I have the answer to a technical question, but exactly the same happens, and always has done, with my own Astra 1.7D, and, I think, with other diesels too. So I think it's a normal characteristic and nothing to worry about.
Astra Oil Light Delay - rg

Ditto my Vx Monterey (Isuzu Trooper)3.1 diesel.

I also get a slight noise sounding like gears rattling, which I guess is the oil pump running dry for a moment.

I assume that the hot synthetic oil drains away quickly, causing the delay in it getting to the pressure sensor on start-up.

Are these Astra engines Isuzu-built? Maybe a charactaristic?

My oil filter if atsump level, so it is not a problem of oil draining fromthe filter.

In all other espects, the oil pressure is fine, 55psi at start up, dropping to 30psi at around 2800, which is in spec.

I reassure myseft that the higher spec of the oil prevents any nasty friction stuff in the few seconds before the light goes off.

Astra Oil Light Delay - Andrew Moorey (Tune-Up)
I have come across this phenomena on a few Ecotec petrol engines and the cause seems to be clagged up oil pressure relief valves possibly caused by the extended oil change intervals. Forte engine flush followed by Texaco semi-synth and Forte Top-End-Treatment has worked so far.

Simplicate and add lightness!
Astra Oil Light Delay - EnormousDerek
I've got a '93 Cav. 1.7TD, which I think has the same Isuzu engine. The oil light on this takes about 3s to go out, most days.

I put the problem down to the fact that the oil filter is mounted inverted. Even though the filter has a 'rubber' one-way valve inside, after several hours, the oil still drains back down into the sump, which means that when the engine is started, the pump has to purge the air from the oil filter before it can start pumping oil around the rest of the engine. The oil pressure switch is on the back of the engine, so I think it's after the filter. (That is the usual arrangement, I believe.)

I always start it, then wait a couple of seconds after the light has gone out before I hit the accelerator and drive away. Without an oil pressure gauge, it's the best I can do. An OPG would be a s** to fit, with the sensor hole right behind the engine.

It didn't used to take quite so long to go out when it only had 70,000 miles on it but now at 179,000 I don't think it's done too bad.

My 135,000 mile '98 Astra 1.7TD (GM engine) has the filter hung from the oil cooler thermostat housing, so the oil can't drain back. Oil light goes straight out on this one, although admittedly the cold-start device does whack the engine up to about 1200RPM straight after starting. The Cav engine only sits at 600-700.
Astra Oil Light Delay - BobG
Had a very siilar problem with another make diesel car which was cured by changing the oil filter to the manufacturer's own - this seemed to have a better one way valve and stopped all the oil draining out overnight leaving me with dry bearings and top end on starting.

Ask Honest John

Value my car