m20 oil issues

[91dodgeram]

i'm new here, but i have a question about my '86 325es. its an American car, so bear with me please. This car is currently in the northern rocky mountains, and has been for approx 6 years. the other day suddenly the oil light came on on the dash and will not go out. it was a cold snap startup (about -20 F) and i let it warm for about 5 minutes then started off to work. about a city block from my house the oil light came on. drove back to the house and took my truck to work. there are no puddles under the car so no major leaks, i checked the oil level and has oil. i use 20-50 synthetic in it as the car has over 300k miles on it. the oil is at the end of its life, but should be thin enough to pump.

here is my question, has anyone ever heard of an oil pump drive shaft breaking? The valve train under the fill cap looks dry, but the car starts and runs like no problems. I'm at a loss for what to do and where to check first.

any help is greatly appreciated.

91 dodge ram

[Brdjo]

Wow, 20w50 oil on -20F?
Maybe I got it wrong but 20w50 should not be used for temp below freezing..
All pass 6 years you run it on 20w50?

[91dodgeram]

really the week before was +30 above and i was ready to change it for winter, but hadn't got around to it yet. the cold snap hit and i was unprepared. but old 20-50 shouldn't be too thick after a good warmup should it? anyways the light didn't come on till a couple hundred yards from my house. are the oil pump drive shafts this "fragile", could it have snapped?

[reggid]

yeah but what about before the warmup.....+30 is still below 0C anyway

the thing about thick oil is it takes more torque to spin the pissy little shaft, its driven off the engine so the engine can supply alot of power to the shaft if the viscosity id extremly high and its going to break much sooner than would be the case if you used a suitable oil. the rate at which oils become viscous with decreasing temp is extremely non linear

[pianist]

I agree it is summer oil and shouldn't be used at winter but before you go and take engine apart check the oil pressure just in case the sensor died. Also check if wire is still attached to the sensor and that there are no breaks in it.

[reggid]

I agree it is summer oil and shouldn't be used at winter but before you go and take engine apart check the oil pressure just in case the sensor died. Also check if wire is still attached to the sensor and that there are no breaks in it.

yes def step 1 check the sensor, i had that on a big $$$ rebuild and where i learn dont use cheap parts (cheap sensor that is )

you can also pull the cap on the intake side of the block to see the shaft etc

[91dodgeram]

i checked and the wire is still attached, is oily, like a minor leak or long time weeping. what cap? to see the shaft? if I can see the shaft, can i remove it from the top to check lower end of the shaft, or is it captured in some way. I will jack it up to see if i have a split oil pan/sump, or if one piece. still don't think its pumping as the rocker shaft under fill cap is really dry looking. anything else i can try?

[Brianmoooore]

Light can't possibly come on if the wire is disconnected from the switch, unless the wire's insulation has failed somewhere and is shorting to earth. This can happen where the wire goes around the front of the engine and heat has made the insulation brittle and fall off.

A well documented failure for an oil pressure switch is for oil to start seeping through it and into the sleeving over its wire. This can make the switch fail 'on' or change the pressure at which it switches.

Remove the spark plugs from your engine for further testing. You'll do far less damage to the crank bearings without the compression load on them.
For further testing, screw a pressure gauge in place of the pressure switch and crank the engine, or as a very basic test, see if oil spurts out of the hole if you remove the switch and crank the engine.

[reggid]

i checked and the wire is still attached, is oily, like a minor leak or long time weeping. what cap? to see the shaft? if I can see the shaft, can i remove it from the top to check lower end of the shaft, or is it captured in some way. I will jack it up to see if i have a split oil pan/sump, or if one piece. still don't think its pumping as the rocker shaft under fill cap is really dry looking. anything else i can try?

to the left of the dipstick tube, picture shows it removed already.

my sensor failed in that oil seeped out between the plastic and metal

[91dodgeram]

thanks for the info, I will try those things and get back to you Wednesday (01-03-18), as I have work till then.

[91dodgeram]

sorry for the late reply to the post, but i found the oil issue. the oil filter came apart internally and was blocking the flow of oil. the switch and the wiring tested good and i have now put winter weight oil in the car. the car is running fine.
i cant seem to get the image to show up, but i got the link, hope this is ok for a google link.

thanks for your help and expertise in the matter

91 dodge ram
https://mail.google.com/mail/u/0/?ui=2& ... &zw&atsh=1

[Brdjo]

Glad to hear you sort it out.. I hope you put in 10w40 now, for the winter period?

[91dodgeram]

yeah, 10-40 and new filter, had to run a heater to get the old oil to flow out quickly, and 2 loads of wood in the fireplace to warm the garage enough to work on it. been really warm here +32F highs and lows around +15.

thanks again

91 dodge ram