Negative 5F Startup Noise

OK-944 · 02-04-2023, 01:46 PM

Coldest start yet for my ‘87NA - 5 below F (likely colder mechanics as it had been down to negative 21 F overnight)…and the engine basically caught fine and built up oil pressure, and indicated 14.2 volts.

But I noticed right away…a steady hum from the front of the engine - seemed to diminish somewhat over the five minutes I had it running, but I didn’t want to take it out for a drive, as its not fun to be stranded at 5 below.

Again, I’d earlier completely rebuilt this engine, plus new water pump, belts, and rollers, and new clutch kit. Has been running really nicely in general.

At any rate…given the above - my thoughts tend towards the water pump or one of the rollers. Maybe a rubbing belt? Noisy PS pump? I’m sharing this on the chance that someone else has experienced something similar. Ideas?

pfarah · pfarah's Garage

It may be one of the roller/tensioner bearings... I once had the same issue.

djnolan · djnolan's Garage

did it increase when you turned the steering wheel?

944 Ecology · 02-05-2023, 02:27 AM

PS pump slow to build up pressure.

OK-944 · 04:12 AM

PS pump...makes sense! (but I did not think to turn the wheel back and forth at startup - darn!)

Also, the PS pump (which I'd resealed) made a horrible noise during the first startup after I'd rebuilt the engine...and to my horror I discovered that I'd way underfilled its reservoir prior to starting. I'd not thought of the PS pump until I turned the wheel, at which point it became especially noisy. But unfortunately, I'd allowed it to run this way for about twenty minutes before actually turning the wheel.

While the horrible (grinding/grating/buzzing) noise went away after I topped up the reservoir, I've always wondered if I'd somehow compromised the PS pump in some way during that first startup - like those little flat metal "vanes" which move in their slots within the "turbine" of the pump are now not quite "right." Probably should take the pump back apart and check at some point.

I guess the larger issue might also involve bits of metal from those vanes floating around inside my PS rack - which I'd also rebuilt.

At any rate...its warmed up a bit today, to 10F and should go up to around 30F - so I'm not sure if I'll be able to diagnose until it cools off again. In the meantime, I'm actually quite hopeful that this is indeed a power steering (pump) issue and not something that involves the engine itself.

OK-944 · 02-05-2023, 01:45 PM

Yup...it was the PS pump making that noise when cold. Completely fine today at 25F, and at 10F a couple of weeks ago. A bit of net research also reveals that this can be a thing generally...so for now I'm not inclined to over think this.

944 Ecology · 02-06-2023, 02:44 AM

Quote:

Originally Posted by OK-944

Yup...it was the PS pump making that noise when cold. Completely fine today at 25F, and at 10F a couple of weeks ago. A bit of net research also reveals that this can be a thing generally...so for now I'm not inclined to over think this.

The pump should be OK... it will give you ample warning when it is about to fail...