Back Pressure in Engine! - Honda Prelude Forum

Taters · 04-05-2004, 04:55 AM

The other day I had the engine running and forgot that I needed to top the oil up so I added some whilst the engine was running.

When I tried to pour some in the filler the pressure coming out of the engine was so great it blew most of the oil away before it got into the the engine.

Is this a noraml amount of pressure or is there something I should be looking at?

The engine runs fine but just checking

Cheers

Mattsy93vtec · 04-05-2004, 05:55 AM

Although I've never tried it, I would assume it's a good thing, it means that your head is getting some good oil pressure which is what you want.

4thGenReady2Go · 04-05-2004, 09:44 AM

Well it would be almost impossible for the engine to be idling whilst exhaust back pressure is pushed back through the manifold, into the head. I'm thinking this is normal though. I have a little story to help lol:

I worked one summer as a lube tech at a honda dealer, and on my first day one of the other minor maint. techs had shown me how to set the oil pump in the parts dept. for when I did oil changes. Anyway, my first oil change was the dealer's customer shuttle (a first gen Odyssey), and I remember going back to the parts dept. and setting it for 4.x quarts of oil, and double checking because it was my first time. Anyway, not knowing how long it was supposed to take to fill 4.x quarts, I stood at the car with my hand on the trigger while i heard the pump click away. After some while I thought things were taking too long, so I checked the oil and, lol, to my surprise, at least half of the entire dipstick had oil on it. I ran back to the parts dept to find that it wasn't set at 4.x quarts, but 40.x quarts. I will maintain to this day that I was sabotaged, and one of the other younger techs there decided to mess around with me. Either way, I called to two of them for help, and they came over, and after checking the level, erupted into laughter. One asked me to start the car, and with the oil cap off I did so. Soon after, as I sat behind the wheel trying to peer under the open hood to see what was going on, I heard "whoa! turn it off, turn it off!" and saw copius amounts of oil being shot out of the filler hole.
This could've all been because I put, oh, 10 quarts of oil in the car, and I've never actually taken the cap off my car while it was running, but I think you're fine, if it was something really bad that caused oil to shoot out of the hole, I'm sure you'd notice it in through the car's behavior. Lol, the funny ending to the story, even after draining a lot of the oil into gallon jugs, there was still a decent amount left, but they told me to leave it. Hours later the short, fat customer shuttle guy with his high pitched voice and crazy left eye (all of this is true) called in and was ranting and raving, carrying on about a whole lot of blue and white smoke shooting out of the exhaust as he drove ... not my fault of course.

ancient · 04-05-2004, 11:03 AM

I have the same problem, I've been told its normal, it goes away if im above 2.5k rpm

brendon2k · 04-05-2004, 12:49 PM

I think you are fine. Why did you add it when it was running anyway?

ancient · 04-05-2004, 01:11 PM

Yea thers no real way to, check the oil when the engines running, cause the crank just churns it all up

neoekai · 04-05-2004, 10:06 PM

haha, thats a funny story 4threadytogo

4thGenReady2Go · 04-05-2004, 10:11 PM

i felt like such a jackass, I could've sworn someone ran back there and changed the setting, lol, could never look at the shuttle driver with a straight face after that.