Dodge Stratus ES '96 oil pressure light comes on

Hi,

I have a Dodge Stratus ES '96 with 130K miles on it. Lately the oil
pressure light has come on. I just changed oil (10W-30) and the oil
level is full (not too full though).

The light only comes on after the engine is warm and it is running on
idle. As soon as I step on the gas pedal the light turnes off. (The
idle speed is about 750rpm). It seems like the engine speed when the
light goes off is variable, maybe related to how warm the engine is?
Sometimes when I stop at a stop light, it is enough to just put the
transmission in neutral (increasing the engine rpm to 750) to get the
light to turn off.

Any ideas?

Thanks,

Olav

 

Could be just a faulty oil sending unit. If it is leaking replace it. If
not, have someone manually test your oil pressure with an external gauge, if
the pressure is ok, replace the sending unit
Glenn Beasley
Chrysler Tech

 

I would you recommend to use 15W-40 for a motor with this miles.
If the problem reoccurs, how about oil filter or then check oil pump.

Regards,

Ralf

 

It is PROBABLY just a bad oil pressure sending unit. That is the first
thing I'd check. I prefer to put a good mechanical oil pressure guage on
the engine to verify the actual oil pressure and to watch how it varies
with RPM. If the engine has 10-15 psi of pressure at idle when hot and
can maintain 30-40 psi on the highway when hot, its fine. If its not the
sending unit, the problem is usually a worn oil pump or worn bearings.
But 130k miles isn't (shouldn't!) be enough to cause that. I've got
several Chrysler engines with over 200,000 miles that still maintain
good oil pressure with 10w30 or 5w30 oil.

 

I agree - classic symptoms of bad pressure switch. When the switch gets
marginal like that, small changes in idle speed can mean the difference
between a closed or open pressure switch (lit and unlit dash light) due
to minor fluctuations in oil pressure.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

Thanks for your answer. Why does this happen only when the engine is
warm?

Also, does anyone know what the "idle" speed should be when the
transmission is in "drive" and the car is still? Mine decreases to
almost 500rpm.

Thanks again,

Olav

 

Oil pressure, especially at idle, drops as the oil warms up and thins
out. Perfectly normal, but if the sending unit is flaky it may be enough
difference to turn the light on only when the pressure is lower (hot oil).

 

Replace the PCV valve. I had exact same problem and it cured mine. I
theorized that my engine (2.5L) was running a little rough at idle - just
enough to lower the rpm's so that oil pump wasn't pumping enough pressure.
I replaced the PCV valve and the idle smoothed out and the light hasn't come
on for last 9,000 kms.