Slowstrike

So sometimes when my truck gets warm and I turn it off for a few minutes when I start it gives me a hard knock that I can feel. I dont know a better way to describe it than Ka klunk no where near a timing chain noise not a rattle or anything near that but a klunk.

usually the sound dies out after one revolution yet I have had it knock for 3 at the most.

Other factors that may be related.

When starting cold it reaches about 1/3 on the temp gauge and drops back down too around a 1/4 after driving for awhile something that It never did before.

It comes and goes sometimes is a bit softer and it wont happen every time the truck warm starts. It runs perfectly fine besides that dam noise.

Most likely I will be doing a compression test in the next day or two id just like to know if this sounds familiar to anyone, thanks in advance

abecedarian

engine mounts?

Kiroshu

Loose Exhaust?

Slowstrike

engine mounts maybe, I do travel many washboard roads but why would it only do it when warm I dunno, the warm factor is the only thing that is a non variable but im going to inspect them anyway.

Exhaust is pretty tight I do have a leaking gasket behind the cat and I did suspect maybe some of the junk inside the cat was maybe broken up so I got underneath earlyer and shook it too see if I heard anything but no.

That does remind me however that I had to re weld the elbow area on the header about a year ago after a pismo adventure. I checked the distal end of the exhaust system not the proximal earlyer today so tomorrow im going to check that weld for sure because it was a weak spot in the past.

Also the MAF or whatever the airbox has a little bit of lag if you play with the throttle cable with the hood up you can hear it kinda suck air and lag when you get on it really quickly like the gate inside is sticking just for a second this could be a separate issue yet I thought id put it out there.

Kiroshu

Well Anything metal loose can make a knocking sound but I mean.....ya know. Yea check that exhaust and if not that its prolly a loose bolt somewhere or somethin. Is your motor missing? If so it could be just knocking up against somethin. Hopefuly its nothin in your valves.

Slowstrike

Im praying its not valves ill find out more tomorrow when I get some daylight.

Kiroshu

If you are a bit mechanially inclined and know a bit in the valves take off the valve cover and check to see that aren't loose and are relatively tight. they are supose to have a tiny bit of side to side play in the rocker arms but other wise nothin much else.

thook

There's a lot of torque at play to get the motor started initially. So, the motor and everything fastened to it does take a jolt. So, do check for something loose.

I know when I was using a heavier weight oil (15W-50) it would make a knock when it first started. It had to be rather chilly outside, though. And, it smoothed out once the oil was circulating and warmed up a bit.

But, if your motor is running good otherwise....after your initial start up....that's a good indicator nothing's wrong internally or really needs addressing right away. You could always put a stethoscope to it and make sure. As well, you could have someone crank the motor and listen for the source of the knock while under there.

Another thought, if the noise actually seems to come from the motor, is if the piston rings have a fair amount of carbon build up = sticky against the cylinder walls, it would be more difficult for the motor to make that first revolution. The piston rod assemblies/bearings and piston rings do tend to have more slack after a lot of miles and could produce some noise (piston slap) until the oil is circulating and the rings have heated up. In which case, you could run a quart of ATF (or Marvel Mystery oil, or something) through to soften the carbon. Run the cleaner a bit and then drain it. See if that helps. Like I said, though, IF the noise does seem to come from the motor.

Note, a knock like that wouldn't come from valve train or the timing chain. So, you can rule that one out.

Slowstrike

"Another thought, if the noise actually seems to come from the motor, is if the piston rings have a fair amount of carbon build up = sticky against the cylinder walls, it would be more difficult for the motor to make that first revolution. The piston rod assemblies/bearings and piston rings do tend to have more slack after a lot of miles and could produce some noise (piston slap) until the oil is circulating and the rings have heated up."



The more I think about it the more this sounds right on. I am gonna try to clean it up like you said and see where that takes me.

How long do you think I should run the atf? 200 miles or so?

abecedarian

ATF is basically high-detergent 0 or 5 weight oil. If you subsituted 1 quart for 1 quart of engine oil, you should be fine, but you may hear a little bit of rod knock on warm starts for a few seconds. You could use a quart of atf with 15w/40 to help counter that and you should be good to go til the next oil change. You need to leave the atf in there as long as possible to maximize the effects. You can use ATF at every oil change if you desire- fill up the crankcase till you're a half-quart or so from full then top it with ATF.

Otherwise, if you're looking for a quick solution, pour in a bottle of seafoam or engine flush, run it a few minutes and do an oil change immediately.

Slowstrike

Thanks abecedarian thats just what I needed to know, and thanks thook and kiroshu. All you guys made my week less stressful

Slowstrike

Well after a few months of the Wtf is that noise I have it narrowed down to near the transfer case area.

I think it might be the trans mounts so abe I guess you might have been correct from the getgo.

I still am yet to find the exact location of where the tapping is happening.

The temp thing was due to several loose electrical connections ( washboard roads suck)

Im keeping this thread updated untill I figure this out so maybe someone else can save themselves the pita in the future.

SteveyCapri

22RE? Mine does the same thing. It'll knock the second it fires up, and sometimes knock a few more times. Probably motor mounts. I haven't bothered looking. I do have a slight engine tick though...

Slowstrike

yep 22re

Slowstrike

Well today after a day of wheeling I found the problem. In addition I also feel like a complete idiot.

I had my friend give me an extra set of eyes and well what did we find? the catalytic converter has a tab that when the cat is rotated upside down and put in (I thought it was better clearance and flipped it a few months ago) the corner of the tab actually taps the frame when the truck starts.

I checked the whole exhuast system several times and swore that it was not coming from there and never looked again. I really learned to NEVER rule anything out after this one.

Now I have a whole new problem that atleast I know what it is

after we had crested the trail onto the paved road we pulled off to have a smoke unlock and get ready to hit the road.

I turn the truck off get out do my thing go back to the truck go to put the key in and look down to see half my key ........................only took me about 2 seconds to figure where the other half was. So who can tell me how to remove and disasemble an ignition? (if this is possible) or any better idea to get the other half the key out.

I ended up having to tow the truck like 5 miles home luckily from a freind. to be honest that was the only time the toy has ever had to be towed how ironic.