I've got this 2004 Lincoln Navigator that I've been using as my do everything appliance car. It hauls stuff, does long trips etc. I haven't done any work on it myself as it just hasn't needed it and/or it's been cold out and I didn't want do DIY in 30 degree weather.
I had a local shop change the oil last year around this time, because I figure it can't go too wrong. It's a full service shop, not a Jiffy Lube. Everything seems okay and this year just today I'm getting close to the oil change mileage again and I need to take a trip with the truck so I bring it back for another change.
Guy comes out after changing the oil and says I was driving around with no oil cap on, BUT there is no oil anywhere in the engine bay and the truck is not low on oil.
The last time the thing got checked it was by them. I have just driven around and have had no reason to remove the oil cap. Is it even possible that I've done several thousand miles in this thing without an oil cap on or did this guy just lose his mind and forget he took it off?
Either way, there is a cap on it now and of course I'm sitting here just a little weirded out by the whole thing.
NickD
HalfDork
1/8/16 1:23 p.m.
Doesn't seem likely to me. In my experience vehicles either throw a CEL for P0171 Fuel Trim Lean or they toss oil every-freaking-where and usually it gets on the manifolds and smells like oil burning. Or both
No oil cap means oil all over under the hood. Every Time. Ask Me How I Know.
I forgot to put the oil cap on once, and only once. It's not a mistake you don't notice.
ask me about terrible mechanics and landrovers... the guy who replaced my engine not only ripped me off for an extra $1000.. but then forgot to tighten bolts on the oil pan, broke the radiator mounts and drilled self tapping screws into the support to hold it into place, and now I found that he never "snapped" the leads on the spark plugs.. She started running rough and throwing misfire codes.. I was getting ready to replace the coils.. popped the hood and the lead for cylinder 8 is just laying there and several others were barely hanging on.
Dr. Hess wrote:
No oil cap means oil all over under the hood. Every Time. Ask Me How I Know.
Glad I'm not the only one to have done this...
and yet here we are bragging about changing our oil ourselves and we take extra time and do the job right 
I keep thinking the guy must have had a brain fart or something and took the cap off and forgot he did it, because as you all say it's just not possible I've been driving around for any length of time without an oil cap on the car and there is no oil anywhere under the hood.
I did it on a customer car myself when I was 16 and working at a shop. Oil all over. Not my finest moment.
Sound a lot like that shop is lying to you. I'd look for a new one.
LuxInterior wrote:
Sound a lot like that shop is lying to you. I'd look for a new one.
But, why would they lie? They didn't charge me to put another cap on the car.
Even if oil somehow didn't spew under the hood, you would've had a vacuum leak with the oil cap off in any modernish car that still has most of its piston rings left, due to the PCV system.
Strange, does it have a super long filler neck? Possible that could have kept the splashing down?
I left mine off once, Didn't take long to notice.... But it was right on the valve cover.
Maybe he took it off and dropped in the engine bay and couldn't find it back. Probably thought telling the story and giving you a cap was easier than removing skidplates during a $30 oil change.
He lost the cap and didn't want to be on the hook for buying a new one.
Harvey wrote:
LuxInterior wrote:
Sound a lot like that shop is lying to you. I'd look for a new one.
But, why would they lie? They didn't charge me to put another cap on the car.
because he was covering up for losing or breaking the cap in the first place. Keep in mind, the oil changes routinely go to the less experienced techs at dealerships and he may have been covering for a newb that dropped the oil cap somewhere in the engine bay or in the oil recovery tank, etc.
I'm not saying it makes sense to do, since honesty is always a better answer here, but sometimes people think that customers can be so unreasonable that they may lie to protect themselves.
itsarebuild wrote:
He lost the cap and didn't want to be on the hook for buying a new one.
That.
I've not lost or forgotten to put the caps back on, but I have still lost several over the decades while the motor was running. I lost one on a Europa TC. That one was attached to a nut on the cam cover with a length of steel wire. The steel wire was gone too. One vanished on the Elise. I think I've lost one on the RN Truck, and there's probably another missing somewhere too. Maybe the Esprit. They were all put on tight. Half of those were the "click click" when it's tight kind. Every time, oil everywhere.
The filler neck on those is offset and baffled it wouldnt have sprayed oil. Ive seen cars come in missing the cap on the mastercylinder.
Duke
MegaDork
1/8/16 3:56 p.m.
mndsm
MegaDork
1/8/16 4:55 p.m.
Dr. Hess wrote:
No oil cap means oil all over under the hood. Every Time. Ask Me How I Know.
I have a fresh rustproofed engine bay in my corolla for that very reason.
You should have said "well, let's check that out" and tell him to take the cap back off and you will take a run down the freeway and he can clean up the result.
oil all over the place..... Toyota 4AF.... slave driven cam is directly under oil cap... if oil cap is gone, slave cam will empty the engine of oil
I remember having a 1st generation Hyundai Excel. I had a cap go missing while going down the highway. While it did not spray oil everywhere, you could smell it.. which was my first clue something was wrong. A wad of aluminum foil squished down tight and threaded into the hole fixed it till I could get home
Best missing oil cap failure I've seen was on a 90s Camry with the 5S-FE 4 cylinder. It splashed some oil on the valve cover (easily wiped up) and the cap was still sitting in the engine bay, so easily reinstalled. The fun came after putting the cap back on.
Driving down the highway for a bit, things got good and hot. Apparently some oil had dripped down into one of the spark plug wells in the valve cover past the seal on the plug wires and started to vaporize after a little while at 3k rpm. Suddenly I hear a pop/thud and the car is running on 3 cylinders. When I pulled over and checked it out, I found one of the spark plug wires blown off and laying on the valve cover with some singe marks on the bottom of it where it meets the plug o.O Popped it back on and drove it home uneventfully for some new plug wires and cleaning out the spark plug wells.
I drove my 2002 F250 with a 7.3 for probably 2k miles with no oil cap. There it was, sitting on the battery when I went to check the oil. Didnt seem to leak any more than usual.
After reinstalling the engine in my old 124 spider, I took it for a spin around the block without the hood. I had oil all over the windshield and myself and the interior.
I haven't forgotten to put the fill cap on since.
