6/6/21 7:33 a.m.

I own a 2008 Miata, purchased new, now with a little over 61,000 miles. It’s been carefully maintained throughout its life and over the last 18 months has been driven very sparingly (1,900 miles total). Last year I began having problems shifting gears, and about a month ago, decided to have a new clutch installed. To get this done, I brought the car to a repair shop that had worked on it in the past.

The clutch was replaced and according to the shop’s work invoice description of what they had done, the major clutch components replaced were the clutch assembly, flywheel, slave cylinder and rear main seal.

Immediately after I picked up my repaired car, I drove to a tire retailer, less than a mile away and had all four tires replaced. During that short drive, I noticed a great deal of engine roughness, roughness that was nowhere evident when I delivered the car to the repair shop a week before. I didn’t think too much of it at that moment though, figuring (wrongly, as it turned out) that it might have something to do with the new clutch and a need to drive the car a while to break it in.

At the tire shop, I watched the entire 4-tire replacement operation from just inside the shop bay door. To perform the replacement, the shop technicians picked my car up simultaneously at the recommended lift points, two on the frame immediately to the rear of the front tire wells and axle and two frame lift points immediate to the front of the rear axle and tire wells. My car was off the ground no more than three feet the entire time the tires were being replaced and that entire operation took less than 30 minutes to complete.

After replacing my tires, I left the tire shop and resumed my drive home, normally what would have been a 10-mile trip. I got less than five miles down the road however, when my engine exploded.

AAA brought the car back to my initial repair shop where I was told that my engine failed because there wasn’t a drop of oil in the crankcase and because of this, most if not all of my main and piston bearings had disintegrated. I was also told that the shop couldn’t/wouldn’t handle any of the fixes that would be needed to get my car back in running shape. They did suggest an alternate repair shop, close by, that could make whatever repairs were needed.

That’s where the car is now, about to have the entire engine replaced.

When this second shop had a chance to look over the damage, they made two observations which I think are significant. First, there is no indication of any oil leakage whatsoever on the car’s underside. Second, that underside is just about the cleanest these mechanics have ever seen.

If as it appears, there was no oil whatsoever in the car when I took delivery of it from the first repair shop after they’d replaced the clutch, where did the oil go? There was oil in it when the car was dropped off to this first shop. Including the trip from my home to drop the car off, I’d driven it without incident around town the week before, easily between 50 and 100 miles.

There is no evidence of oil leakage in my garage and this garage is the only place the car has been stored since its last oil change. The work done by the tire shop did not cause the problem either. Nothing they did, including lifting the car off the ground, was done anywhere near the underside of the car. That’s supported by what the second shop said about the condition of the car’s underside. And to the best of my knowledge, oil doesn’t simply evaporate away into thin air, particularly from a sealed environment like an engine sump.

So if all this is true, then where did all the oil go between drop-off and pickup? One explanation is that one of my first shop’s mechanics, for whatever reason, as they were replacing my clutch, drained my oil and forgot to fill it back up when they were finish.

Is there any other explanation someone can come up with (other than me screwing up royally)?

BoxheadTim GRM+ Memberand MegaDork
6/6/21 8:05 a.m.

My guess based on your description is that it was either aliens teleporting the oil away or someone draining the engine oil as part of the clutch work, although I'd be a tad confused as to why they would do that - maybe to replace the rear main seal. I leave it to your imagination which of the two possibilities might have had a higher likelihood of occurring.

Problem is likely going to be the ability to prove anything - I'd definitely have the second shop document as much as they can and in as much detail as possible.

Not sure what the second shop is planning to do repair wise, but  if I were in that situation I'd have them drop in a good used engine. I don't think there is that much point in trying to repair what you have if it's been run without oil for any meaningful length of time. Might be perfect time for a 2.5L swap, too.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) SuperDork
6/6/21 8:11 a.m.


¯\_(ツ)_/¯ PowerDork
6/6/21 8:16 a.m.

I'm going to bet that they drained the gear oil before taking the transmission out, and somebody *also* drained the engine oil, went "oops" and told nobody, and... here you are.  That makes more sense to me than draining it on purpose and forgetting to fill it.

Was the oil light not on the whole way to the tire shop?

John Welsh
John Welsh Mod Squad
6/6/21 8:52 a.m.

In reply to ¯\_(ツ)_/¯ :

I wonder if anyone working on the Miata got soaked working on the trans.  

I envision this happened:

  • Boss to low wage employee:  "drain the oil/fluid"
    • I'm not sure whether boss said oil or employee heard oil but wrongly the oil was drained, not trans fluid.
  • Mechanic then took out trans with a big soaking of trans fluid
    • Assumption is made that low wage employee just never drained the trans fluid.
    • No one thought to think that the oil was drained instead.   

Flaw to this theory:  How is it that no one saw the oil light on????   No shop test drives?  Not seen while owner was driving???

Donebrokeit UltraDork
6/6/21 8:56 a.m.

Has anyone ever claimed this era of engines have oil consumption issues? Even if it's not proven the first shop may try to use this claim as a way out.

John Welsh
John Welsh Mod Squad
6/6/21 8:59 a.m.

Keeping the tire shop out of the story (because I think they are irrelevant) we then have...  

Picked up from trans repair and drove 1 mile...then drove 5 miles more before explode.  No sign of leak and no leaking on the floor of the trans repair shop.  Not stated but the shop may have put 1 mile on the car too as a test drive but not enough to get to highest temps and find real trouble. 


My hypothesis would be:  there was no oil in the car when it left trans repair shop.

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) GRM+ Memberand PowerDork
6/6/21 9:00 a.m.

Terrible situation. This will be a test of character for shop one. 

I do wonder about the oil light/gauge. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
6/6/21 9:02 a.m.

IIRC the NC oil gauge is a calculated likely pressure based on engine speed and temp. It does have a switch that will flatline the gauge if there is no pressure at all, but I don't think there's a light. Just a gauge that is really a light but that hides the information with noise. 

I don't know what the pressure is on the switch offhand. It was 7 psi on older ones. 

I would have a very serious conversation with that trans shop. 

BlindPirate Reader
6/6/21 10:02 p.m.

Someone is going to do it so I just wanted to be the first one to encourage you to use this opportunity to swap in a 2.5 liter 

Tom Suddard
Tom Suddard GRM+ Memberand Director of Marketing & Digital Assets
6/6/21 10:10 p.m.
Jesse Ransom
Jesse Ransom GRM+ Memberand UltimaDork
6/7/21 12:09 a.m.

In reply to BlindPirate :

The very first reply beat you to it. But I think you're part of a growing chorus...

Rodan SuperDork
6/7/21 9:09 a.m.

The simplest explanation is usually the correct one, and in this case that's: "shop 1 drained the oil and forgot to re-fill'.  Any other explanation requires too much speculation.

I would have a serious conversation with the owner, but it's a rare business these days that would take responsibility for such a screwup.

As a related anecdote, my wife once drove our '13 NC without oil for about 1.5 miles without ill effect.  It was (mostly) my fault, as the parts shop had given me the wrong oil filter (for NA/NB), and I didn't notice.  I should have, because we had NA, NB and NC at the time.  Anyway, it screwed right on and torqued properly, but the mating surface was incorrect, and a month later it unscrewed itself.  Anyway, I trailered the car home, refilled it with oil, and it ran fine and never displayed any issues in the ensuing year before we sold it.  That included a track day or two.

I would speculate your drive to the tire shop only finished it off after a test drive started the damage.  


Forgot to add:  another vote for 2.5 swap!

Snowdoggie (Forum Supporter)
Snowdoggie (Forum Supporter) Dork
6/7/21 10:00 a.m.

Years ago a gas station left the drain plug loose after an oil change on my 914 and the oil ended up all over 635. 

One laywer's letter later the owner of the gas station ended up buying me a rebuilt 2.0 Porsche motor and an installation at a local independent Porsche shop. I also got a rental car for a week. The gas station actually had insurance that covered that sort of thing. 


RaabTheSaab New Reader
6/7/21 10:51 a.m.

I’ll also echo that shop 1 simply drained the oil and forgot to refill it. This happened to me in my DD civic. Luckily I noticed that the car was running really strange after about a mile into driving home. Years of driving Hondas have conditioned me to check the oil first. The civic was bone dry and I refilled it promptly. Never told the shop, but also never went back. Like most things, Occam’s razor likely prevails here. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
6/7/21 11:14 a.m.

Just for fun, I tried to find the specifications for the oil pressure switch in the NC - ie, at what point does the "gauge" read L instead of an imaginary number. I can't find it, but I did come across this troubleshooting procedure that worries me. Seems that the "inspect the oil pressure" step should be highlighted...

1.Turn the ignition switch to the ON position and verify that the oil pressure gauge reading indicates L or below.

2.Start the engine and verify that the oil pressure gauge operates.

• If the oil pressure gauge does not operate, inspect the related wiring harness.

― If the related wiring harness is normal, inspect the oil pressure. (See OIL PRESSURE INSPECTION [LF].)

• If the oil pressure is normal, replace the oil pressure switch.

pirate HalfDork
6/7/21 11:25 a.m.

What is involved to change the rear oil seal in a Miata. Do you have to drop the oil pan, I don't know. If so they forgot to refill with oil. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
6/7/21 11:55 a.m.

Not in an NA, NB or NC Miata, I'm not sure about the ND. But that doesn't mean someone didn't drain the oil.

SVreX (Forum Supporter)
SVreX (Forum Supporter) MegaDork
6/7/21 12:06 p.m.

When's the last time you had an oil change?  Do you have a receipt?

If the shop is of any size, I'm betting that they have cameras that would show what happened, and insurance to pay for it. 

But they'd have to be willing to share the evidence...

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