Honda Oil Light Comes on with A/C Problem

Hi All,

Could you help identify this problem? I have an '97 Honda Prelude SH
with 167K miles. The oil light comes on in the afternoon when I drive
for a while with the A/C on. I drive for 30 min. on the freeway with
the A/C on then when I slow down to under 10mph or stop the oil light
begins to flicker and then blinks continuously. The rpm goes really
low but the engine doesn't shut off. It's hot in Houston. I turn off
the A/C and the oil light still flickers. I don't have this issue in
the mornings or at night. Does the heat have to deal with it?

I check my oil level and use Catrol Syntec Blend 10w30 and the levels
are normal. Is it the alternator? I don't think so, b/c my electrical
system seems normal. WHat do I need to change or replace?

ANy ideas?

Cheers

md

 

not good news. if you're real lucky, it's the oil pressure sender, but
that's unlikely to be the problem. you can also try replacing the oil
pump, but it's much more likely the motor is shot, worn main bearings
being the most likely cause. has this motor ever been rebuilt? look
into the economics of buying a used import japanese replacement motor.
rebuilts rarely last very long, so their value is limited.

 

Try a thicker oil... 10w30 dino, or even 10w40. It may help keep the
pressure up.

What does your temp gauge do? Could be that your engine is getting warmer
than usual, thinning the oil even more than normal.

Finally, with the car in neutral, turn the A/C on... Do the revs drop? If
so, you may have a bad switch somewhere. Most cars will boost the RPM to
compesate for the extra load of the A/C. A more accurate way to test is to
disconnect the A/C pressure switch, then start the car and turn on the
A/C... RPM should definately increase as the engine compensates for the
compressor - and since the switch is unplugged, the compressor doesn't
actually kick in.

 

The light blinks when the oil pressure sender is producing unsteady
readings. It could be the sender or something more serious. I suspect the
sender; my daughter's 93 Accord began blinking and a new sensor fixed it.

The cheapest and easiest way of troubleshooting is to blindly replace the
sender (or have it replaced). If the sender is bad, this will fix the
problem. If the sender is not the problem, you will have to take it to a
professional but you will know it is really an oil pressure problem and you
will have a new sender!

In any event, get this taken care of immediately.

Mike

 

wrote in

The oil light is supposed to come on when the pressure is below something
like 6 psi. If the pressure is hovering around 6, the light will flicker.

1) If your revs drop below normal idle and do not recover, your A/C idle-up
is not working. This could be all the problem is. Where is the tach needle
when it's idling with the oil light on?

2) Defective pressure sender. Have the oil pressure checked as soon as
possible to rule this item out.

3) Worn bearings. Oil pressure is primarily a function of the main bearings
of the crankshaft and the big ends on the connecting rods. If they're worn,
the oil pump will be unable to maintain pressure with thin, hot oil and low
revs.

 

When the A/C is on the tach needle is low, close to 0rpm or half of
1rpm. Turning off the A/C helps bring it up a little, but still low.

I'll check it out. Thanks for everyones help!