I have a 2001 Sonoma with a 4.3. It started making a knocking noise after I replaced the seals. It sounds like a bad crankshaft bearing. I just went to start it up to isolate the noise and coolant just shot out across the garage. It came from the driver side front corner. It looks like it was splashing off the control arm. I found this on top the control arm
Is it the seal from the coolant overflow cap? but iy looks like you have bigger problems
No this is rubber. Its very mailable.
Had one at work that did that, I can try and call the retired mechanic, but do not recall the solution. I think they just sent it off to auction.
That would be cool. I’m about there
20 year old 4.3 pickup, I’d send to a scrap yard. They might give you a couple bucks based on the weight.
There has to be hope
I have to be out of this house pretty soon. I’m packing up for the next few weeks and taking a ridiculous chemistry class. I don’t know how I will have time.
Has anyone ever messed up a crankshaft bearing just by rotating it? I cant make sense of why it would do that…
Maybe that item you show has nothing to do with the coolant leak and simply fell onto the control arm sometime in the past.
I have a 98 Sonoma with the 4.3 but don’t feel like poking around in the dark to identify that part. I will take a look tomorrow in the daylight though. I seem to remember a plug in the radiator tank (driver side) around the engine oil cooler line fittings but do not remember it being malleable rubber. (engine oil cooler optional)
Maybe you could add water into the radiator filler neck and see where it gushes out.
Yeah that’s a good idea.
Is that the seal for the brake master cylinder cap? You might check to see if yours is missing. If it’s the present and the same it could be that it fell out sometime in the past with a prior owner and they replaced it rather than hunt for it. Matter of fact I will go check mine right now with a flashlight…back in a few.
Well, that item appears to be the master cylinder cap seal so it’s not the cause of a coolant leak.
Fill it up with water and if nothing comes out then one has to wonder about the radiator cap, radiator to overflow tank, and overflow hose.
Thanks for doing that. I’ll do that when I get done working tomorrow. I got way too much heat tonight. Need to sleep
I should have said this at the start. My serpentine belt was off when the coolant spewed everywhere…
Sure there always is, but not holding any for this one.
Already has an unexpected unexplained knock.
I think it’s a done deal. If a crank bearing rotates it covers an oil feed hole starving that crank journal of oil.
Too much clearance between bearing and crank, maybe?
Pop the master cylinder cap off tomorrow and if yours is missing then you know where it went.
I tend to think the coolant issue is a minor problem. With a belt off and a mechanical cooling fan it will overheat and puke coolant out past the cap or overflow system.
These radiators use plastic tanks so you might look the area over around where the cap is located for some cracks.
Last summer the tank around the cap on my Sonoma was fine one minute and had a 6 inch crack the next. It happens with age and heating cycles.
You were right about the master cylinder cap. Not sure why it was down there, but it’s been a while since I worked on my truck.
My truck was on for maybe two second when it happened.
The tank was on the other side also
Just a wild guess by someone who is not a mechanic but you tried running it without the water pump, which is AFAIK driven by the serpentine belt. I can’t imagine the result would be pretty.