Please help. 1985 4runner. I just did a DIY rebuild for the first time. Block was decked, brand new head and MLS hg. In last 10k miles new vacuum hoses, water pump, oil pump, injectors sent out, all new gaskets and more.

Used lots of assembly lube and removed ego fuse to prime engine with oil before first start. Starts fine but there is an intermittent hissing noise emitting but can’t track it down. Checked all idler bearings and triple checked vacuum hoses.

please review video and let me know if anyone has had a similar experience. Thanks for any advice or input.

 

Dude, you posted under For Sale.

I would first spray water on it running to see if that changes anything. I would also remove the belts and check alternator bearings, water pump, idler pulleys, A/c clutch. Run it with no belts to see if that changes anything.

 

Thanks for the quick response. It was my first post and obviously I messed that up.

Tonight, did remove all belts one at a time to make sure it wasn’t any idler bearings, PSP or alternator.

Does the water just help track down where the noise is coming from on the engine?

Thanks again

 

i use water to determine belt noise and vacuum leaks; leak stops when you hit it with the water..

 

moved to correct section

 

How do the intake hoses look going to the AFM and throttle body?

 

I’ve had the vehicle for 9 years and have never replaced it. It looks ok but maybe it’s got a leak somewhere. I’ll look into it a little more. Thanks.

 

The flexible corner pieces of that big tube often wind up with cracks that can be very hard to see, until they're flexed the right way. They are, fortunately, pretty well available. I think you can tell the difficulty in replacing them for yourself

Also, and I'm sorry, I can't resist this one, but could a snake have crawled into the engine someplace, and is hissing because it doesn't like being disturbed by the engine running??
Sorry, I just had to say it...

Good luck!
Pat☺

 

At this point I would have welcomed the snake. I’ll be replacing the flex connections on the ends of the intake tube next week. They do look a little old. Hopefully that will make a difference