Oil Pressure Light at 1600 (cherry popped)

[karmavore]

My light started flashing on my S4 as I passed 1600 RPM yesterday for the first time in my short period ownership. In reading the previous posts on the subject many say not to worry but some, like Techspy, freaked out over it. What's the real deal? Here's the scoop..

Yesterday before going out I checked the oil and it was about half a quart low. On my way to pep boys the light flashed for the first time but stopped after adding some oil. I drove for a little while, nothing too spirited, and then garaged her until this afternoon...

Today I checked my level again and she was still a tad low so I added a just a little bit and took her out again. After 30 minutes of highway driving the light flashed again as I passed 1600RPM, and continued to do that dance so until I stopped.

I topped off with M1 10W-30 (cos that is what the PO was using) and am likely due for a change and filter (which I'll do in two weeks).

Thoughts?

Luke.

[lotusguy]

Luke,

10W-30 is a big No No! You want to go with 20W-50 Mobil 1. If you're running 10W-30 now, don't wait two weeks to make the change unless you don't plan on driving the car 'til then. Happy Motoring! ...Jim'85TE

[karmavore]

Ugh... that's what Scotsdale Lotus was puttng in the car over the **20K miles** the PO owned it! How bad be talkin'????

Luke.

[lotusguy]

Hi,

If changed religiosly and using Mobil 1, the potential is not too bad. But you will get bad pressure and readings. These engines need a heavier oil and Mobil 1 20W-50 is the best all-around, especially for the turbo bearing - less potential for 'Coking'.

I saw on the other foruum someone suggested your filter was the problem, not so. The wrong filter is likely to produce higher, not lower readings.

I use the NAPA Gold filter #1521, made by Wix and one of the accepted substitues. Happy Motoring! ...Jim'85TE

[Skerd]

I had this exact same problem with the red oil light flickering on and off in an S4s. It was the oil RPM alarm relay. The part cost $ 129 and the labor was $ 57. My dealer uses Mobil 1 15W-50 in every Lotus model.

[karmavore]

Thanks guys. I'll change the oil and filter today. Are the NAPA filters readily available?

Luke.

[karmavore]

It just doesn't add up. I would think that if the oil was much too light the pressue light would be on all the time, but it just started happening.

I reached out to the PO to see what he knows and I'll call Scottsdale on Monday, hopefully that will shed some light on the situation...

Thanks again fellas.

Luke.

[dr.hess]

There is a relay, mentioned above, that turns off the oil pressure light below a certain RPM. I forget exactly what, but I am sure someone will tell you. Probably right around 1600, where you notice the light flickering. Its purpose is to not display a low pressure warning while you are idleing, because the pressure will be low then anyway.

Dr.Hess

[sanj]

karmavore said:

It just doesn't add up. I would think that if the oil was much too light the pressue light would be on all the time, but it just started happening.

In a normal car this would be true, at least at lower RPMs, but the Esprit is a bit odd. Due to the wide pressure swings (normal) between idle and high-RPM operation, Lotus was unable, or unwilling, to use an idiot light sender that wouldn't turn the light on when idling hot. In other words, the acceptable idle oil pressure is so low that the idiot light would be illuminating frequently when idling. Their solution, which is downright scary, is to disconnect the idiot light circuit via the RPM relay whenever the RPMs drop below 1600, thereby ensuring the light never comes on below that point. Even if there is ZERO pressure.

Your situation indicates that the oil pressure may be below the warning point at an engine speed above 1600 RPM, thus the flickering. Step 1 is definitely to put the correct weight oil in. Mobil 1 15W50, Castrol SynTec 5W50, or Valvoline Synthetic 20W50 are all acceptable weights.

The gauge should track the idiot light, is it also indicating low readings?

As far as the problem just showing up now, are you driving the car more, or has the weather gotten hotter?

Cheers,
Sanj

[95lotus]

If Lotus of Scottsdale has been putting in 10W-30, then I am certainly happy that I do my own oil changes. I'd be interested to hear what you find out from them.

FYI, I always put in Mobil 1 Syn, 15W-50, and I use the K&N Performance Gold oil filter, HP-2004.

Bill
'95 S4S

[karmavore]

I will Bill, I also sent a mail to Steve to see what he knows.

Luke.

[lotusguy]

karmavore said:

Thanks guys. I'll change the oil and filter today. Are the NAPA filters readily available? Luke.

Hi,

Any NAPA store will carry that filter. Wix makes a very good product and it is much cheaper ($4 vs $12) for the Lotus filter. It has the appropriate anti-backflow valve and sufficient flow characteristics.

Bear in mind, that any filter does a relatively poor job of cleaning the oil, that is not really it's purpose. Rather, it is designed as protection to remove chunks from the system. These can be combustion by-products, metal shavings (hopefully not too many) or any dirt or residue which somehow migrates into the engine. This is why you need to change oil every 3000 mi. You expell all the dirt, moisture, carbon etc. along with the oil. Most oils will protect much longer (Mobil 1 used to advertise as 25k mi. protection, but they never stated that you still must change the filter every 3k mi. and replace the quart or so you lose with the filter, but you need to eliminate the dirt and debris from the engine and changing the oil accomplishes this. The oil, not the filter is designed to keep alot of this junk in suspension and not clogging up the engine. Happy Motoring! ...Jim'85TE

[autocross7]

95lotus said:

If Lotus of Scottsdale has been putting in 10W-30, then I am certainly happy that I do my own oil changes. I'd be interested to hear what you find out from them. FYI, I always put in Mobil 1 Syn, 15W-50, and I use the K&N Performance Gold oil filter, HP-2004. Bill '95 S4S

After some of the things I have heard and seen dealers doing to cars... I'd believe almost anything. Change your own oil or at least take the shop what you want used (and watch them use it).

Using a greased silicone plug in place of a pilot bearing takes the top darwin award though!

Drive topless!!!
Cameron

[karmavore]

What Oil do we all like best? I've used Mobil 1 since I've done my own oil changes (~8 years) but am open to comments...?

Lotusguy - Thanks for all the knowledge, sincerely. Can you tell me in what ways specifically the lighter weight 10W-30 will do less of a job protecting my engine than a 15W-50, and in what ways the harm could show?

Thanks again!

Luke.

[karmavore]

sanj said:

The gauge should track the idiot light, is it also indicating low readings?

Yes, just above the red line at idle after she's warm.

sanj said:

As far as the problem just showing up now, are you driving the car more, or has the weather gotten hotter?

No hotter than Arizona where she's lived with 10W-30 for the past 18 months....?


Thanks Sanj,

Luke.

[Lotusguy]

karmavore said:

Lotusguy - Thanks for all the knowledge, sincerely. Can you tell me in what ways specifically the lighter weight 10W-30 will do less of a job protecting my engine than a 15W-50, and in what ways the harm could show? Thanks again! Luke.

Luke,

The motor oil has essentially three functions.

First is to provide a layer between the bearing surfaces on which the Crankshaft, ConRods, Cam Lobes, Turbo bearing etc. literally float on this layer of oil with no metal to metal contact. A lighter weight oil is thinner (lower viscosity) and will be squished out, especially once heated, from between these metal parts allowing metal to metal contact. This is why a 50 weight (higher viscosity) oil is necessary for the 9XX engine. There is also less friction for the motor, and it's parts, to overcome between the metal parts and this oil layer as opposed to metal to metal contact. This is what they mean by lubrication.

Second, your oil provides 60% of your engine cooling, not the anti-freeze as commonly thought. Remember, the coolant only flows around the cylinders and through the head, it has little effect on heat generated at the Crank or ConRods. Again, a lower viscosity oil is not as conductive of the heat and therefore cools less efficiently at these critical points.

Third, the oil is designed to trap all the <5 micron particles (metal, carbon, etc.- probably 95% of all the foreign matter in your engine) and hold them in suspension so they do not damage the engine or cause premature wear.

There are many variables determining what type of oil should be used in an engine stemming from actual design, manufacturing tolerances, etc., which is why different engines have different oil requirements. Hope this helps. Happy Motoring! ...Jim'85TE

[95lotus]

autocross7 said:

After some of the things I have heard and seen dealers doing to cars... I'd believe almost anything. Change your own oil or at least take the shop what you want used (and watch them use it). Using a greased silicone plug in place of a pilot bearing takes the top darwin award though! Drive topless!!! Cameron

Cameron, I have to agree! I've been doing mine 'cause it's a pain to drop the car off and pick it up in Scottsdale. I found out later from Steve, the PO of Luke's car, that they charge $150 for the oil change compared to the $45 for doing it myself. Maybe I should have done Steve's for $100! (He lives about half a mile away from me.)

Bill
'95 S4s

[karmavore]

Steve insists that they've been using the correct oil, which, in all honestly, is consistent with the evidence...

1) light did not come on till it was low on oil and since when I topped off with 10W30

2) Steve says the oil light never went on for him

3) The written invoices from Scottsdale say "20W50" but the "digital" ones say "10W30." Perhaps its the first thing in the database the tech came to when filling it out.


...but if that's true why the _uck would they be so sloppy as not to write the correct weight. If I had known it could've keep me from buying the car in the first place. Anyway... I'll call Scottsdale tomorrow and see what's up.

Luke.

[karmavore]

Lotusguy said:

Luke, The motor oil has essentially three functions.

Thank you.

Luke.

[95lotus]

karmavore said:

Steve insists that they've been using the correct oil, which, in all honestly, is consistent with the evidence... 1) light did not come on till it was low on oil and since when I topped off with 10W30 2) Steve says the oil light never went on for him 3) The written invoices from Scottsdale say "20W50" but the "digital" ones say "10W30." Perhaps its the first thing in the database the tech came to when filling it out. ...but if that's true why the _uck would they be so sloppy as not to write the correct weight. If I had known it could've keep me from buying the car in the first place. Anyway... I'll call Scottsdale tomorrow and see what's up. Luke.

I don't recall Steve ever mentioning the oil pressure light coming on, so Lotus probably has been putting in 20W-50. I've only had my car in there once, and that was because it was due for the C-service right after I bought it. The mechanic there at the time (he left not long after that) talked a good talk, but after I picked up the car and found that he hadn't done any of the other things on my list of stuff to look at, I was rather disappointed. I think that more than anything got me back into working on my own car again.

Anyway, sounds like the problem is solved and the car is okay. Steve is the type of guy that takes really good care of a car like that and I don't think he pushed it near it's limits very often.

Bill
'95 S4S