Main IndexAuto Repair Home Search Posts SEARCH
Who's Online WHO'S
Log in LOG

Search Auto Parts

89 S-10 Blazer knocking and hissing noise

  Email This Post

New User

Oct 22, 2010, 11:52 AM

Post #1 of 3 (2012 views)
89 S-10 Blazer knocking and hissing noise Sign In

1989 Chevy S-10 Blazer, (not sure about the L its 2 wheel rear drive if that helps) over 265k miles.

Before you look at the miles and decide, I have to say it ran great until this morning. I was driving down highway going about 65mpr when i noticed a faint noise. When i slowed to turn thats when something happened and the knocking started. I can't tell you what happened all I know is it didn't sound right and feel right. The knocking didn't stop when in idle or anything. I checked my belt no cracks or damage, checked fan it wasn't loose or hitting anything. I checked oil saw it was in need so put 2 quarts in. While doing this I noticed a hissing noise like air releasing, so I checked all hoses and caps everything looked in place. I turned the engine on and the knocking was gone but the hissing was louder (prolly cause the knocking was gone i was able to hear it clearer) and had a little bubbly sound to it. I took my blazer around the block and the knocking came back not as bad but was present and the hissing got worse. obviously my bro (who drives my truck more than I do) forgot to check and add oil. Other then the noise it runs fine. The hissing sound comes from behind the filter close to the winshield. I have no idea whats going on or where to look closer. Any suggestions and or point me in the right direction would be great.

Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Oct 22, 2010, 12:14 PM

Post #2 of 3 (2004 views)
Re: 89 S-10 Blazer knocking and hissing noise Sign In

That doesn't sound good. Running a car out of oil is almost always terminal. The knocking pretty much confirms that. You were on borrowed time with the mileage. Running it out of oil is a mistake it can't survive.


We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.

Veteran / Moderator
Sidom profile image

Oct 22, 2010, 12:44 PM

Post #3 of 3 (1998 views)
Re: 89 S-10 Blazer knocking and hissing noise Sign In

I can't hear the noise but since the oil was way low, you better let this sit, cool down & check the coolant. It sounds like you were overheating & the more you drove it the worse it got.....

Don't try to take the cap off if it's hot & has pressure in the system. Feel the upper hose and make sure you can squeeze it together and there is no pressure. If it's rock hard let this sit for a few hours.....

  Email This Post

Feed Button

Search for (options) Privacy Sitemap