Mystery of the missing oil cap!

[StruthJones]

Hi, my Yaris Hybrid 2018 had an MOT and service with an oil change in November, but I've been ill a lot since then and have only driven locally except for this weekend when I drove about 250 miles. This week on my way to work, the orange engine light came on and almost immediately, so did the red oil light. I stopped immediately and got the bus into work. Later, I found that there was no oil cap and that oil was all over the engine and there was no oil on the dipstick. I contacted the garage and the mechanic said that it was impossible that he could have forgotten to put the oil cap back, as he had to run the engine for a while for the MOT. He advised topping up the oil, and until we could get a replacement oil cap (which seem in short supply) to cover the hole with foil and cable ties. I did that and started the engine but there was just a clunk and then nothing. I'm assuming that the engine has seized.

Has anyone heard of an oil cap coming off on its own?

Any advice on this matter would be greatly appreciated. Thank you!

[Bper]

Hi Ruth,the mechanic is probably right, forgetting the cap entirely is improbable during an oil change and MOT.It's more likely the cap wasn't tightened properly, causing it to vibrate loose during your long drive.With no cap, oil leaked out, potentially leading to insufficient lubrication and engine seizure as you suspect. It's crucial not to run the engine until a mechanic diagnoses the problem.If you haven't already get the car towed.

The mechanic will assess the damage. In a best case scenario, replacing the oil, filter, and possibly the oil cap might suffice.

In a worst case scenario, engine repairs or even replacement could be necessary. If the original mechanic is at fault, discuss compensation for repairs due to their negligence. This might involve a conversation with the garage manager. Depending on the outcome you may need to take legal advice

Keep a record of your communication with the garage, If you are unsure about their response, consult a trusted mechanic or consumer organisation for legal redress and further guidance.

Remember, it's crucial not to run the engine until a mechanic diagnoses the problem. Hopefully it will not come to this. Hope this helps 

[Cyker]

I've also never heard of such an occurrence on a Yaris! I've always had the opposite problem and struggled to unscrew the filler cap even if I don't tighten it very strongly, so I reckon either it wasn't put on or it wasn't screwed down as there's no way it could come off on its own if it was screwed down even slightly tightly!

I winced when I read you tried to start the engine - Running an engine with no oil in it is one of the worst things you can do to it; Hopefully that hasn't done irreparable damage, but will likely have shortened its life if it's seized up...

Bper's advice is spot on as usual!

[APS]

Never ever heard of an oil cap come off. For some reason, I have experimented with this and you really do not need to tighten them much at all. They just don't go anywhere. As Bob said, the only possibility is that the mechanic didn't tighten it (at all) or forgot to put it back. 

 I think the cap has been missing a while. It takes some time to empty out all the oil through the filler hole. My guess is the mechanic had a 'senior moment' and forgot to put it back - as unlikely as it sounds. 

Keeping fingers crossed you get it sorted in the end. 🤞

[MikeSh]

3 hours ago, StruthJones said:

and the mechanic said that it was impossible that he could have forgotten to put the oil cap back,

Well, yeah. He's not going to say "oops, sorry about that" is he?

It's going to be hard to prove, but as others say keep meticulous records of all correspondences.

[Stevie J]

How do we know if the mechanic did the oil change before the MOT - he might well have done the MOT and then the service afterwards, in which case he could well have forgotten to put the oil cap back on, if he refilled the oil, checked the level and then say the phone rang and he got distracted and walked off for a while, then returned and slammed the bonnet down without realising he had left the cap off. Depends on where he put the cap as well when refilling the engine, if he left it sitting on top of the engine, it may well have fallen out and got lost when you drove off, so he would not have found it on his workbench afterwards and known he had forgotten to put it on.

Don't hybrids sometimes not start the engine immediately you turn the key on, initially starting on electric power until you get to a certain speed when the engine then cuts in, so it is not set in stone that the engine has seized - it may be possible to get a spanner on the crank pulley and see if the engine can be turned over by hand first before doing anything else - that would show if it was seized or not, although I think its highly unlikely it would be seized if the owner turned the engine off as soon as the red oil light came on. Usually you have to run an engine a good few minutes with the oil light on before total seizure occurs, so at this point I wouldnt be too worried about the engine being a write off. See if the engine can be turned over by hand first before taking next steps.

If in the unlikely event the engine has seized up, it may well be pretty difficult to lay the blame on the garage as they will deny leaving the cap off any may even say that you yourself may have lost the cap in the months following the service. They are unlikely to voluntarily want to foot the bill for engine replacement as it aint going to be cheap. It may be necessary to claim on your own comprehensive insurance or take advice from your own insurers about how to proceed if the engine does end up being seized and the garage refuses to admit liability.

[Mjolinor]

Look for the cap under the bonnet everywhere, under the wheels, on top of the plastic pan (assuming it has one). Worth looking in the car, under the seats, in the boot.

If you find it anywhere then the mechanic left it off.

Oil change will always be done before MOT because of the emissions test.

[TonyHSD]

Very likely the cap was not tightened up properly and with engine vibrations this is what happened. 

[bathtub tom]

3 hours ago, Mjolinor said:

Look for the cap under the bonnet everywhere, under the wheels, on top of the plastic pan (assuming it has one).

I dropped the top of an oil can somewhere in the engine bay when I changed the oil. It wasn't on the floor or anywhere nearby when I drove the car off the drive, so I assume it's still down there, somewhere.

[Roy124]

10 hours ago, APS said:

 I think the cap has been missing a while. It takes some time to empty out all the oil through the filler hole. My guess is the mechanic had a 'senior moment' and forgot to put it back - as unlikely as it sounds. 

I disagree.  Our local filling station in Cyprus would do an oil change and jet wash.  I was just pulling in as the car that had just been serviced was pulling out.

Oil was pouring from the engine bay and I got him to stop.  On opening the bonnet the entire compartment was covered with oil. 

[Roy124]

@Cyker winced when I read you tried to start the engine -

She did suggest she had refilled, capped with foil and secured with tie wrap as per the advice.

Good advice if you had dropped/lost the filler cap, but at this stage with the warning lights a tow was the obvious solution.   

Another 'quote' to add to the discussion list with the mechanic. 

[anchorman]

Whether the cap was left off or not tightened, it still goes back to the last person entrusted with the job.  For those saying it vibrated off, go slacken your filler cap, start the engine and watch what it does.  Even if it finds a sweet spot where the vibration might make it undo several turns, it wont go far, if it’s a model with an engine cover it won’t go anywhere.   One of the responsibilities of being in the motor trade is that if you make a mistake, you do the right thing and the person that should be paying for this lot is the last person that touched it.  I’ve been in the motor industry and I’ve dealt with warranty and that’s how it goes.  

[APS]

10 hours ago, Roy124 said:

I disagree.  Our local filling station in Cyprus would do an oil change and jet wash.  I was just pulling in as the car that had just been serviced was pulling out.

Oil was pouring from the engine bay and I got him to stop.  On opening the bonnet the entire compartment was covered with oil. 

It can vary from engine to engine, but in general it should not shoot out oil. That is a sign of a very unhealthy engine with blow-by and/or blocked PCV system. In which case oil can indeed come out of all kinds of orifices 🙂 The loss of oil you get in a healthy engine with the cap off, is splashing from the cam lobes (or whatever is closest to the filler hole) slinging oil out. All Toyotas have a small splash guard in the opening that reduces this. 

8 hours ago, anchorman said:

Even if it finds a sweet spot where the vibration might make it undo several turns, it wont go far, if it’s a model with an engine cover it won’t go anywhere.

In fact, they tend to tighten themselves up as there should be a slight vacuum on a good engine.

Here's what it looks like on an Aygo with the 1KR-FE. (the drops you see are rain drops)

[Roy124]

34 minutes ago, anchorman said:

Whether the cap was left off or not tightened, it still goes back to the last person entrusted with the job.  

An issue here can be the time between the work and the problem. It is about 4 months since the Service.

Many of us will check under the bonnet after picking the car up from servicing.  The distrustful amongst us may even undo that filler cap to check for fresh oil and lack of emulsion. 

Too easy for the garage to blame the owner.

[Hybrid21]

Hi Ruth, if the garage was the last to open the bonnet in November then obviously they are responsible.

The problem is the time lapse, ie 4 months. I appreciate that you have been ill and probably not used the car as much, but I don't understand that you have not looked under the bonnet since having the service done ? Indeed the first thing you should do after a service is lift the bonnet and check everything looks ok.

You do have some responsibility Ruth to do basic checks on your vehicle 🙂

[Roy124]

Iain, I had had the same thought but we don't know anything about Ruth apart from her ability to publish a photograph and use this forum.

There may be many reasons why someone would not open the bonnet.  My mother in law relies completely on the garage.  I doubt she could even open her bonnet; she is 98.

My wife could open the bonnet but lacks the reach to fasten the stay on the YC (or Corolla).  In the past she could open the bonnets of the SAAB or Mercedes  but relatively the Toyota is too heavy.

[Jimota]

As a 20 year old I became the owner of a 1969 rusty MK1 Ford Escort and was proud of the fact that I could do my own servicing.  In those days replacing spark plugs, points, topping up the various fluids, changing the air filter and engine oil was fairly straightforward.  However, after completing a service and taking the car for a run, I noticed steam belting out of the radiator grill.  After carefully opening the bonnet and preventing myself from being scalded, I noticed that the radiator cap was missing.  At first, I thought there was no damage but the cylinder head gasket had blown.  My mate managed to repair it a minimal cost but to this day I often wonder who the silly person was who either fitted the cap incorrectly or forgot to put it back on. 🤔

[Jimota]

My mate used a genuine gasket to sort the problem but do any of you remember people using trimmed cardboard from Kelloggs Corn Flake boxes to create a seal? 

[Cyker]

People did that for real?? I thought that was a joke!!  

 

[anchorman]

38 minutes ago, Cyker said:

People did that for real?? I thought that was a joke!!  

 

Err, no.  I can vouch for that 

[Rhymes with Paris]

My pal Denzel set off for the metropolis in a 1987 astra van some time ago,he did check the oil before travelling,but misunderstood the method, procedure, and indeed any part of oil checking altogether.

Turned out he filled the engine with oil up to the valve cover, then fortunately forgot to put the oil filler cap back on thus preventing blowing out the core seals.

Of course the excess oil blew out all over the van and everywhere else, I think they still talk about the A1 oil slick at carpenters lodge even nowadays.

 

 

 

[Mjolinor]

2 hours ago, Cyker said:

People did that for real?? I thought that was a joke!!  

 

I often use cornflake packets to make gaskets.

It is the only choice once your vehicle gets over a certain age unless you have a large bank account.

[MikeSh]

3 hours ago, Cyker said:

People did that for real?? I thought that was a joke!!  

 

With a decent sealant and enough clamping force ... yeah. Gaskets should be 'just' dealing with slight imperfections in the metal faces. If the faces are machined to close enough tolerances you shouldn't need anything in theory, though in practice a little sealant would be good insurance.

Compression fittings in plumbing don't need anything beyond the metal-metal contact. (I know, softer metals, etc, but the principle is still there.)

[bathtub tom]

I recall reading that BSA Gold Stars didn't have a head gasket, the head was lapped to the cylinder.

[Mjolinor]

1 hour ago, bathtub tom said:

I recall reading that BSA Gold Stars didn't have a head gasket, the head was lapped to the cylinder.

It didn't really matter anyway because no one could start them.