Motor knock while warming up...

[emmahumpfritter]

Quick question for the gurus: My tercel has 225K'ish miles, I think it runs pretty good for it, but does knock a little while it's warming up (especially if you move it ). Normal? Worrisome?

[takza]

I had a similar knock...turned out to be the fuel pump at the back of the valve cover. Use a stethoscope or vac tubing to locate it?

[Neu]

Could be sticky valves, once they warm up they stop sticking.

[emmahumpfritter]

Is there any concern about this? My festiva does the same thing (and has over 225K on it) still runs flawlessly. I have no problem letting it warm up before driving, just wondering if it's signalling a potential problem? Thanks, Brenton

[Neu]

Mine knocks pretty much all the time, and it gets 32mpg. I'm not gonna mess with it.

[xirdneh]

I drove one of my tercels around for several years with those symptoms.
Never had a problem but always wondered what it was. When I removed the engine (which still ran fine) and took it apart it had one cracked piston.

[toughtercel]

since I bought 83 4WD last spring 2009 , I maintance check throughly every thing before become as daily driver , I was surprise that all the camshaft lobe are deep wibbles, compression test are V.G. and NO BACK FIRE ,they were all roughtly 4/1000 too tight then back off to spec but ran terrible and shave off to 2/1000 are ok , since then drove 7,000 km still going strong , but it is knocking with shhhhh sound, plan to replace, kept on delaying my self

[Petros]

knocking can be everything from no harm at all to something really bad is about to happen. You have to isolate where it is coming from by using a long screw driver against your ear (probe around the various engine parts), or a mechanics stethoscope.

You can also pull the spark plug wires one at a time, if the knocking stops at one cyl it is likely bad, it means the bearings are shot. IF it does not stop after pulling each of the plugs wires in turn, than it is likely camshaft or valve related, not so bad and likely will never be an issue.

It could also be piston slap, a worn piston and cyl allows the piston to slap around in the bore until it warms up. this is just a matter of time. My first Tercel did this for two years, and than the piston skirt failed and bundled up the piston. It was still driveable but it smoked like crazy and made a lot of bad noises after that. When I pulled it apart I was surprised it was still running. I had to totally rebuild the motor with over boring the cyl and use oversized pistions because the bores were worn way too big to save.

Good luck.