1991 Prelude Oil Flow Diagram? help - Honda Prelude Forum

AJHS2011 · 10-13-2010, 10:22 PM

Alright guys, i need some help with my prelude. its a 91 2.1L. b21a1 engine, just replaced all the valves and belts. now after it runs for about 3-4 minutes, i have a major oil leak...possibly coming from some hoses or something. I need an Oil Flow Diagram so if anyone can help me out with this, that would be great! thanks guys email me at basketballkidd5@hotmail.com if you have any information for me.

Colfax · 10-13-2010, 11:15 PM

There are no external oil lines on the b21a1. All the oil is contained within the engine. The oil cooler is cooled by engine coolant, and is located under the oil filter.

Are you sure it's engine oil? It's common for the power steering pump or lines to leak and spray oil all over the engine bay.

Anyway, here is a link to an online factory service manual. It's mainly for the 88 Prelude, with supplements for 89 and 90. But the b21a1 and the b20a5 are identical as far as the oil flow is concerned...

Honda Shop Manuals - 1988 Prelude

AJHS2011 · 10-16-2010, 01:21 PM

Yeah it's engine oil. It leaks bad around the oil filter, it's not the oil filter though. I bought an online copy of the 90-91 prelude manual and i have it downloaded on my computer. My next step i think i will drain the oil again and remove the oil filter...maybe find something then..

Colfax · 10-18-2010, 03:25 PM

It could be the oil cooler gasket. The oil cooler mounts to the engine and the filter is fitted to the cooler. Or maybe the old oil filter gasket stuck to the block the last time the filter was replaced, and now it has a double oil filter gasket. I've seen that happen on cars that have had jiffy lube or some other discount oil change place change the oil.

AJHS2011 · 10-19-2010, 03:54 PM

Thanks im gonna check that out the next time i take a look at it I've been quite busy lately and haven't had time. But yeah thanks for that.