Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: mattg on December 26, 2009, 08:09:32 PM

Title: Oil light
Post by: mattg on December 26, 2009, 08:09:32 PM
No sooner did Vinnie help me figure out my ignition switch problem yesterday when the following started:    this seems to only occur when engine is warm and car is in gear.  example:  Idling at red light.  oil light will come on intermittently.  usually it is extremely dim for a second then goes off for a few seconds.  and repeat until I start moving.  If i am shifting between gears, like doing a k turn,  it comes on brighter for a second and goes off.  There are no codes except for system pass 11.  the oil level is correct.  This doesn't happen, so far, until the engine reaches operating temp.
Title: Oil light
Post by: jandmmustangs on December 26, 2009, 09:22:44 PM
Whats your pressure at operating temp at idle?  Also what is it revving at operating temp?
Title: Oil light
Post by: mattg on December 26, 2009, 10:00:59 PM
J&M -  the revs are about 1000 rpms steady.  I don't have an oil pressure gauge in the dash.  just the light.    I do have an aftermarket oil pressure gauge that i bought for a past project.  i suppose i can install temporarily.
Title: Oil light
Post by: jandmmustangs on December 26, 2009, 10:19:29 PM
That might be a good idea to install it.  Even if you just let it hang in the interior.  I dont wanna ruin your xmas or anything but low/no oil pressure at idle warmed up is a sign of worn main,rod, and cam bearings....  Im hoping its just a faulty sender.  A mechanical gauge is the best way to tell.
Title: Oil light
Post by: jcassity on December 28, 2009, 02:54:31 AM
milk it with rotella on a thicker oil for a while if the pres is low.

20psi is bare min to teardown.
Title: Oil light
Post by: mattg on December 29, 2009, 09:58:05 AM
i'm getting anywhere from 10 to 15 at idle.    the second i shift into gear it spikes down to 10.  if i turn the wheel while in park it spikes down to 10 or 12.  if it's just sitting there idling its 15.    It rises in conjunction with the RPM's as i'm driving.  at 2000 it's just over 30.

i'll try the rotella for a while.
Title: Oil light
Post by: mattg on December 29, 2009, 10:23:17 AM
on the bright side this gives me an excuse to start planning and saving for a new long block.  That won't happen for quite a while though.  in the meantime,  i need to baby this engine for quite a while.  beside the thicker oil,  any other advice to prolong the death?
Title: Oil light
Post by: V8Demon on December 29, 2009, 10:45:44 AM
It's a little low, but nothing dangerously low.......It shouldn't be setting the chime off.....

Read the following:  http://www.foxtbirdcougarforums.com/showthread.php?t=26435
Title: Oil light
Post by: jcassity on December 29, 2009, 01:10:03 PM
keep in mind the sump / screen may just be a little dirty, either way you may want to check that out first.

I do not know if there is even enough room to simply lower the pan and get to the sump bolts, never done it on my cars but can on the 351 bronco.
I do know that if i were to attempt it, i would add blocks of wood and shims to gain the most height as possible on the engine as it is jacked up.  I would also undo the tie rod ends and the rack/pinion bolts so the rack can lower a little giving the pan extra drop.

either way, not sure if anyone here has been able to get the room needed to simply get to the sump.  am positive you can not replace a pump without separation of the engine from the trans,, just not enough room.

what would be neat is if you could go into the oil drain hole with a tool that let you see inside the pan and guide a small vac hose connected to a shop vac, then you could see the screen and vaccuum it clean again.

if you have ever added that thick oil treatment stuff by stp, its probably all gobbed up on the bottom of the pan and the sump screen is working hard just to pull oil in.

Another idea would be to remove the oil filter and add air pressure to the path leading to the sump. This would be the hole off to the side (not the inside of the threaded tube.  Blowing air back through the sump might work to back flush the screen.  You would now have to fill the pump back up with something to prime it like some thick gear oil riged up to a hose you can squeeze new fluid into the same hole you blew out.

just some ideas for you to stew on, some of the ideas above could be done on your next oil change.
I have never cleaned a sump like this, i think i brought it up here a few years ago, not sure on the replies but either way , im sure you can let us know if the pres goes up after doing this.
Title: Oil light
Post by: jcassity on December 29, 2009, 01:14:43 PM
Quote from: mattg;304277
i'm getting anywhere from 10 to 15 at idle.    the second i shift into gear it spikes down to 10.  if i turn the wheel while in park it spikes down to 10 or 12.  if it's just sitting there idling its 15.    It rises in conjunction with the RPM's as i'm driving.  at 2000 it's just over 30.

i'll try the rotella for a while.


in my case, reving the motor did not yield no more than 20 psi while idle speed showed 17.  if 50% of your engine running time is in stop/go patterns, your doing more harm than good 

you may be able to milk it.
Title: Oil light
Post by: bike70ride on January 06, 2010, 05:17:55 PM
My 3.8L does the same thing, but it's not consistant.  Sometimes it'll stay on continuously even at normal driving speeds, then it'll eventually get better and better and then go off completely.  Interestingly, this mainly happens in the winter.  Especially bad with 10W-30 oil.  I run 15W-40 in the summer and VERY rarely see the oil light.
 
Engine is a little noisy, but no knocking or oil burning to speak of.  Oil always changed since I've owned it at 2500 miles or so.  Engine is a rebuilt of unknown exact mileage, but was told it had about 40K on it when installed, so it's got about 150K on it by my guesstimate.
 
I've never checked the actual oil pressure with a guage...perhaps when it warms up again...
Title: Oil light
Post by: jcassity on January 07, 2010, 01:57:23 AM
Quote from: bike70ride;305327
My 3.8L does the same thing, but it's not consistant.  Sometimes it'll stay on continuously even at normal driving speeds, then it'll eventually get better and better and then go off completely.  Interestingly, this mainly happens in the winter.  Especially bad with 10W-30 oil.  I run 15W-40 in the summer and VERY rarely see the oil light.
 
Engine is a little noisy, but no knocking or oil burning to speak of.  Oil always changed since I've owned it at 2500 miles or so.  Engine is a rebuilt of unknown exact mileage, but was told it had about 40K on it when installed, so it's got about 150K on it by my guesstimate.
 
I've never checked the actual oil pressure with a guage...perhaps when it warms up again...



and the million dollar solution lies within the external oil pump gear set you can buy.  there are some other parts contained in the kit typically and its called the proportioning valve.

Problem 1-  when you remove the filter and the small half dozen 10mm bolts, you can very easily get the gears out,,they just fall out.
the proporitoning valve requires the timing cover be removed.  the proporitoning valve is located at the top area of where the gear set is and extracts to the right (ie- where the timing cover meets the engine block).  There is  a tiny 1/2'' freeze plug contained in the kit because in order to replace the proportioning valve,you must drill the old one out.

the old proportioning valve just sits there and slides back and forth in its wonderful aluminum housing.  I suspect that the burrs and wear cause the prop valve to stick on some of our cars.  Mine did (3.8 as well) because when i looked at the housing, i noticed a s along the side and when i manually moved the prop valve, it stuck several times out of 10 tries.

either way, if you got a constant 20psi plus presure, then try another sending unit.
Title: Oil light
Post by: Haystack on January 07, 2010, 05:08:42 AM
I think my engine may be pretty tired now. Has less power then any of my past cars. 3.8's even. My pressure sender is going i hope.. I'm going to swap it out with my oil change tomorrow and see what happens.
Title: Oil light
Post by: bike70ride on January 07, 2010, 02:34:34 PM
Quote from: jcassity;305399
and the million dollar solution lies within the external oil pump gear set you can buy. there are some other parts contained in the kit typically and its called the proportioning valve.
 
Problem 1- when you remove the filter and the small half dozen 10mm bolts, you can very easily get the gears out,,they just fall out.
the proporitoning valve requires the timing cover be removed. the proporitoning valve is located at the top area of where the gear set is and extracts to the right (ie- where the timing cover meets the engine block). There is a tiny 1/2'' freeze plug contained in the kit because in order to replace the proportioning valve,you must drill the old one out.
 
the old proportioning valve just sits there and slides back and forth in its wonderful aluminum housing. I suspect that the burrs and wear cause the prop valve to stick on some of our cars. Mine did (3.8 as well) because when i looked at the housing, i noticed a s along the side and when i manually moved the prop valve, it stuck several times out of 10 tries.
 
either way, if you got a constant 20psi plus presure, then try another sending unit.

Thanks for the ideas!  Sounds like a possible Spring project...not for the below zero temps we've got now!