ehall

What happens if you have a bad oil sender unit? What happens to the guage reading? How do you know if it's just the guage rather than the unit? What size wrench is needed to remove it?
TIA

User 41221

Usually, its pegged at the top of the gauge if the sender is bad. IIRC, its a 24mm wrench, but I'll have to look it up to be sure.

supes6

check the wiring too, the spade connectors can get brittle and short out. any short in the wiring leads to the gauge being pegged at 5+. I think I had to remove some other stuff to get a wrench in there when I replaced mine.

V2Rocket

it can give all kinds of readings, really low ones too - one time leaving santa cruz in traffic my oil light came on at idle and it said i had like 1bar, and while cruising it only got to like 3.5 bar, and it wasnt THAT hot out...

i pulled over to let it cool, checked oil, it was fine, and i made it the 400 miles to san diego without a problem just by keeping it 3000+ rpm, swapped to my spare sender and all was well

Techno Duck

Key on but engine still off, the gauge will usually read at something other than zero.

You can hook up a variable potentiometer to wiring to determine if its the gauge or not. Another option is to hook up an early oil pressure gauge and run it directly off the battery / leads on the oil pressure sender (use completely separate wire leads). If you get different readings from your dash gauge you have a wiring or gauge issue.

Check this thread for a long and drawn out 'test everything and find out it was just the sender' experience i had a few years back...

https://rennlist.com/forums/924-931-...-question.html

I forget the size of the sender but i think 24mm is correct. Its a pain to change and i highly recommend disconnecting the PS pump from the bracket as it makes it alot easier rather than fighting to fit a wrench in there. I was unable to find a stubby 24mm wrench..ended up just using a short adjustable on it.

BTW, if you do get a new sender i would consider getting an OE VDO type sender. I picked up an aftermarket FAE sender and it ended up being bad right out of the box (this was mentioned in the above thread). The VDO sensor is about $100+ while the aftermarkets range from $25-40.

User 41221

+1 on the VDO sender recommendation. You get what you pay for on that one.

Removal is much easier if you get the sway bar and power steering out of the way, but I did rig up a "dog bone" wrench that allowed me to do the work without removing either. In retrospect tho, its much easier, even tho it takes longer, to remove the aforementioned components.

ehall

Thanks guys.
Originally it was giving symptoms of being wired backwards. The oil light was on, but the guage read over 5, as soon as the key was turned. So I reversed the wires. Now it either reads 1 or above 5. I know it isn't an engine problem, so i'm going to have to replce the think. I'm going to have to find a wrench for it. I don't think I have a 24 or 27mm, which ever. I saw where someone ground down a 15/16 wrench to fit. I may try that rather than buying a metric.
Thanks for the input.

Bri Bro

Get a crowfoot wrench set, much cheaper and fits in small places.

ehall

i think I saw you recommend that to someone else some years ago, and I put it on my list, but never got one. Thanks for the heads up. I KNOW that I need one.
Any preferences?

MM951

I use a stubby 15/16th craftsman wrench to get at the sender without removing anything else. Break it loose and you can spin it out with your hands, even if they are big *** hands.

PorscheDoc

Yea, i have seen them give different readings when failed. Some spike to over 5 and don't ever move, and some eventually work their way down low after driving to the point where the light will come on (mimicking worn rod bearings).

Bri Bro

I picked up a set at Sears since they are local. Northern tools and (if you want low cost) harbor freight carry them. Some have a curved front like a brake wrench but I like straight jaws that slide straight on from the side.

http://www.sears.com/shc/s/p_10153_1...o=4&blockType=