1991 Oil Light - Toyota Nation Forum : Toyota Car and Truck Forums

cressibowii · 03-18-2009, 11:14 PM

hey guys, ive got a 91 cress, after the car has been running for a bit (like 15-20 min) at idle or complete stop, the oil light will come on. I think it could be the oil pump, but not sure.

i could really use some help to find out what it is.

thanks guys

zero_gravity · 03-20-2009, 09:59 AM

having had the same problem with my old '90 cress the first thing to do is put a new oil pressure sender in. its located right near the oil filter under the dizzy. get an OEM toyota sensor - the aftermarket ones don't like the 7M and will usually set off the light when they shouldn't.

alternatively get a test gauge and see what happens.

***kamesama980*** · 03-20-2009, 11:06 AM

it may be the pump, yes. zero_gravity is right though, the sender usually goes out first. I WOULD suggest getting an oil pressure gauge. the 7m only specifies 3-4 psi at idle. cheap or thin oil will also do it.

The light is triggered by a pressure sensor on/off switch set at about 2-3 psi. as the heat cycles and age get to it, the switch gets out of calibration, triggering higher or lower than it should.

What oil is in the engine now? if you're running 5w30, I'd move to 5w40 (if you can find it. usually only in synthetics) or 10w40. keep in mind your problem is after the engine and oil warm up, so you want a bigger warm viscosity number which is the second number. IE going from 5w30 to 10w30 does jack good.

cressibowii · 03-20-2009, 05:58 PM

so i should get a new oil pressure sender and switch to a different oil? do you think synthitic oil would be best?

mark_vdh · 03-22-2009, 08:04 PM

what oil is in the engine atm?

same thing was happenng with my 7M, new sender fixed it
if you really did have a problem with the oil pump your car wouldn't be running anymore

zero_gravity · 03-23-2009, 11:25 AM

what we're trying to say here is that its not necessarily the pump. before you start wasting an ass load of money on a problem that may be non-existent find out what that pressure is. if its fine, just a bad sender.

if its not then start looking for other issues.

cressibowii · 03-23-2009, 04:14 PM

thanks alot for your imput guys

***kamesama980*** · 03-25-2009, 12:59 PM

Quote:

Originally Posted by mark_vdh

what oil is in the engine atm?

same thing was happenng with my 7M, new sender fixed it
if you really did have a problem with the oil pump your car wouldn't be running anymore

not necessarily. I ran with the light on for 3 months. turned out the pan was mashed against the pickup and it really wasn't getting enough oil. it was sort of a two-fold problem though, it wouldn't happen till I'd been driving a bit and it pulled some big stuff against the pickup screen to block what little was left open. before I got the engine from him, my buddy got the oil changed at a quicky-lube type place that forgot to put the drain plug back in and drove 5 miles before they called him.

keep in mind oil pressure doesn't hold parts apart, it's presence and viscosity does. pressure just makes sure its there.

91Cress · 11-06-2009, 07:03 PM

I read all the posts here. I think I am running 10W/30. I have 2K on the oil change that a local mechanic did, put in too much oil (on my 88 dodge truck as well).

The oil light goes off under strong acceleration (not 25-30 in town). But it only just came on today (Fri) and I have to make a trip of about 3.5 hours on Monday. Most of the time driving it today it was on.

Sounds like maybe a sensor problem (though had run it on a forest dirt road the last time I drove it).

I was hoping to be able to drive the 3.5 hrs to the airport and then take care of it on the return, when I have time and am passing through cities (from Chico, CA on north). It is about 1.5 hrs to get to a place where I can get a filter and oil to change it.