heavy tapping at cold start

[1997chevydriver]

Ill stick with doing crank, rod bearings, mainbearings, timing set, oil pump and associated gaskets for less than $500

 

[kn1ght]

Does it sound like this?????(minus the power steering noise of course, it was -15*f that morning)



http://www.youtube.com/watch?v=ecmB27xYHAc

Louder than my powerstroke...

 

[GMCTRUCKS]

Try Castrol High Mileage oil the stuff has something in it that took a tick sound we had in a SUV before so I started using it on my truck evfen tho I don't have a ticking sound but I have high miles and the oil made a believer out of me.
Good luck! RS

 

[pike_mazter]

My 98 does the same thing, I just let her warm up before pulling out. Normally ticking goes away at idle after 15-20 seconds and goes away for acceleration at 1-2 minutes. Only happens when it hasn't been ran for 8 hours and is a bit worse when its cold. Winter weather usually she gets 10-15 minutes of idle time in the driveway before I drive. She enjoys it.

Warmer summer weather sometimes its not even an issue.

 

[m13hty]

added a quart of lucas and it aint dont it since... lol

 

[Snowman]

My '98 does the same thing. There is a TSB about it for the Vortec engines. Knock caused by excessive clearance on the 5th main bearing.

Bulletin No.: 99-06-01-003

Date: April, 1999

TECHNICAL

Subject:
Engine Bearing Knock Noise,
(Re-support Crankshaft, Select-fit Undersize Connecting Rod Bearings)

Models:
1999 Cadillac Escalade
1996-99 Chevrolet and GMC C/K, G, P Models
with 5.0L or 5.7L Engine (VINs M, R - RPOs L30, L31)

Important :GM Canada Dealers require prior DSM authorization to apply this bulletin.

Condition

Some customers may comment about an engine "knocking" noise.

Cause

A condition may exist in some engines where, the crankshaft is NOT being evenly supported by all five crankshaft bearing inserts. In these engines, the number 1, 2, 3, and 4 crankshaft bearing inserts are supporting the crankshaft, and the number 5 crankshaft journal (rear) has excessive clearance relative to the number 5 crankshaft (main) bearing cap insert. In this condition, the crankshaft flexes under load, and pounds on the lower number 5 crankshaft (main) bearing insert creating the knocking sound. The engines were originally built with 0.0006 in. undersize crankshaft (main) bearing inserts in the number 2, 3, and 4 crankshaft (main) bearing locations and 0.001 in. undersize insert in the number 5 crankshaft (main) bearing location. The service procedure listed below addresses the above condition by lowering the crankshaft at the number 2, 3, and 4 crankshaft (main) bearing positions (increased crankshaft (main) bearing size of the lower crankshaft (main) bearing inserts) and raising the number 5 lower crankshaft (main) bearing insert (undersized insert) in order to properly contact the number 5 crankshaft journal surface. These engines may also exhibit a connecting rod knocking sound. In these engines, the connecting rod knocking sound is caused by excessive connecting rod bearing clearance.

A customer concern vehicle may exhibit one or both of the above stated conditions.

Correction

Follow strategy-based diagnostics for engine noise listed in the front of Section 6 of the Service Manual.

Some additional key points:

Rod Bearing Knock - Occurs on initial engine start-up, and can also be heard as high as 1,500-1,800 RPM. Rod bearing knock typically diminishes or completely goes away when the engine reaches normal operating temperature.

Crankshaft Bearing Knock - Crankshaft (main) bearing knock sounds deeper in the engine and also sounds more muffled. There are two different types of crankshaft bearing knock.

^ Short duration cold knock typically occurs for 1-5 seconds on engine cold start-up only, and almost always occurs on vehicles equipped with an engine oil cooler.

^ Hot knock occurs less frequently, typically occurring in very hot ambient temperatures, and can be heard up to 2,000 RPM.


Technicians can increase the likelihood of reproducing bearing induced knock sounds by slightly depressing the accelerator pedal while starting the engine.

 

[sewlow]

Good info ^^^ !
Try adding some 'EOS'. 'Engine Oil Supplement'. Used to be a dealer only item, now you can get it at most parts stores. Contains graphite.
The ole man used to swear by that stuff. And he's an anti-additive guy! ("Snake Oil!") He used to put it into cabs that had 4-5-600,000 miles. Quietened most of the weird noises on high-mileage engines.
Cheap fix, if it works for you. Can't hurt to try it.

 

[trailer-trash]

added a quart of lucas and it aint dont it since... lol

mine has done it for years...lucas used to quiet it...haha...used to...but it still only does it for 10 seconds or so and shes ready to go...I usually let the ole girl warm up a few though..it does have 300k on it now.

 

[kn1ght]

added a quart of lucas and it aint dont it since... lol

Most have different detergents in them. But they are all certified by the oil engineers, that's what that little gold star on the oil bottle is. Some just have a few extra ones.

 

[m13hty]

yeah the noise came back after a few days. it doesnt do it as often as it did before. but it is still doing it from time to time. i got a set(16) lifters from a buddy all new in box for $50. but they are roller lifters like the factory ones are. everyone tells me those should NEVER go out.. so idk.. i paid $50 for em like i said but i have yet to install em. my 98 has 259k on it..