weird rattle on startup

[SuperHO]

98 SHO...cams welded...maintenence up to date. It's not rod bearings (i certainly know what those sound like). On cold startups, it makes an ungodly rattle from either the engine or tranny. It bugs the **** outta me. What's causing this?

 

[roland]

the lawn gnome......

that's a kinda scary noise to have happen

 

[stephen newberg]

Need to know more. Does it happen only when the car is in park? If it is there when driving while still cold, does it increase or decrease, change with speed, etc? Nail it down with a bunch of characteristics and there is a better chance someone can point you to the rigth thing.

pax, smn

 

[Reka]

Sounds like the rattle that most V8's make. It's just the chain tensioner. There's no problem with it. Kirk mentioned that he's fixed one for a customer who insisted on getting it fixed.

 

[SuperHO]

K....it doesn't last long enough to know if it changes pitch with throttle....it only lasts for about the first second and a half after a cold start up. then it goes away.

 

[Mr Anonymous]

K....it doesn't last long enough to know if it changes pitch with throttle....it only lasts for about the first second and a half after a cold start up. then it goes away.

Watch your oil pressure light when this happens. You'll notice that the noise stops as soon as the oil light goes out when your main chain tensioner gets pumped up with oil pressure . Pretty common on at least 50% of V8 SHOs, some cars it's just more noticeable.

 

[SHOZ123]

Use better oil

 

[98TRSHO]

Paul what would suggest? Only Synthetic or a blend or ca I just go with a better brand regular oil?

 

[SHOZ123]

I like the 5w40 synthetics. Shell Rotella is a good and and can be had at WalMart for the cheap.

EDIT: But now that I think about it maybe a 2 bottle Auto-RX treatment would be of more help.

 

[JVANBUREN]

I use mobil one synthetic and it sounds like the same problem i have its the chain tensiner in the head in between the cams i switched to a little thicker oil and it doesnt do it as much. Im pretty sure its the spring in them that go bad but its all good once it gets oil pressure.

 

[Brett]

From what ive heard its not a good idea to switch from regular oil to synthetic. Espicially on a higher mileage motor (IOW anything over 10k miles). Because the synthetic is thinner or somethin I really dont know the logic of it but thats what i hear around here.

 

[CerberuS]

From what ive heard its not a good idea to switch from regular oil to synthetic. Espicially on a higher mileage motor (IOW anything over 10k miles). Because the synthetic is thinner or somethin I really dont know the logic of it but thats what i hear around here.

When i was a mechanic awhile back , i heard several horror stories on the switch from regular to syntetic oil on high millage cars. I heard too , you had to start it with that , and its gonna be the best oil you'll ever use.

Most syptoms of the switching over was oil consumption.

Donno if its still true , but thats what ive heard from other mechanics , and its enough for me not to do it on mine.

 

[Mr Anonymous]

You should also avoid black cats, opening an umbrella in the house, and walking under ladders; they can be even more dangerous than switching to synthetic oil. :shakehead

 

[SHODWN]

Stepping on cracks, breaking mirrors, thinking dirty thought in a Boston church...:laugh_ti:

 

[Red Devil]

I'll preface by disclosing that I'm an Amsoil dealer. That said. Those synthetic oil myths did start for a reason.

When Amsoil came out with the synthetic oils (and then Mobil shortly thereafter), they both had issues with older, high milage/older (closer to 100 k not 10k miles) seals and they did their job too well in an era where tolerances were a bit.... "looser". Todays seals, and the additive packages in the oils (Amsoil and Mobil 1 use the same PAO basestocks) have improved and the tolerances in todays cars are more exact.

Sythetic is better at it's job than conventional. Think that through and you should figure out why people have problems now (particularly breaking in flat tappet cam engines). Do a bit 'o independant research and you'll find that today's true PAO synthetics are better than any of the class III synthetics (like castrol) and far far better than conventional oils.

What I would personally worry about on the SHO, those whose cams have not been welded, is that the better lubricity, better detergent package and more uniform molecule structure may exacerbate any 'fitment' issues that you may have on your cam assemblies.

Mmmkay, I could go on, but I'm running on three hours of sleep and been up for close to thirty. 'Night all.

 

[me6894]

wait whats exacerbate mean? lol are you saying that you dont recommend synthetic to someone without welded cams?

 

[rickshaw]

Exacerbate is my situation of un-welded cams and I just switched from synthetic after 150K miles.

I just couldn't stomach the cost for synthetic at Jiffy ****!