Newbie with a dead Tacoma

It's my first time posting anything on anything...A few days ago I forgot my oil cap and drove about 20km without it. I checked the dipstick and it showed level was still fine but after replacing cap and doing another short drive I noticed the check oil light coming on (I don't have an oil pressure gauge) and could hear a very very faint rattle sound when I pushed on gas. Today I was driving it to the shop to get oil pressure checked when I started losing power, the engine started banging and she died. I'm having a hard time believing that I just blew my engine because I had no oil cap for 20 km. Could the oil pressure have gotten that low in that time and if it was a pressure issue, why didn't it build up after the cap was back on? I don't see any oil drops under my truck.

 

Leaving the oil fill cap off had absolutely no bearing on your engine seizing up, especially if you had checked your oil level and it was fine. To lose enough oil to seize, your engine compartment would have been drenched in oil and there would be an absolute mess under it.

 

Thanks for the comments, I'm grateful for any ideas. There was a fair bit of oil under the hood but didpstick showed level over half (and I topped it up.) I have the 3RZ 2.7 lt. engine. I feel like an ass for not parking it as soon as the light came on.

 

Your oil pump is a typical gear pump.leaving your cap off would not cause it to loose pressure. it will puke oil out the hole making a mess, if ran long enough like this the engine would be starved of oil and your oil level would be so low you wouldn't have enough oil in your sump for the pump to draw from causing low pressure and then your oil pressure light should go off giving you lots of warning before you run your bearings dry..... So it sounds like you spun a connecting rod bearing which sucks because that means your bottom end is toast

 

Hope it dont turn out bad, good luck

 

Welcome and hope it all works out for you!