Fortec Five
Newbie
Posts: 27
Reg: 03-20-09
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12-08-22 03:32 PM - Post#2851067
It's been years since I have posted on here. Nothing to do with my 1996 Chev. Tahoe 5.7 V-8. But, it's our housekeeper that has a problem with her GMC Terrain 4 cyl engine that is making a "tapping" noise at cold startup, but the noise subsides when the engine warms up. I always refer tapping in an engine due to the lifters problems.
She's taken it to three local repair shops here, and they all think it has to do with the timing chain. I told her to have the shop to drain the oil and install diesel oil and a quart of transmission fluid and see what happens. She told me the repair shop never heard of this being done.
Anyone out here have a suggestion?
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 gchemist
Member #271 Senior Chevytalk Moderator
Posts: 25841
Loc: Austin, TX 78748
Reg: 05-09-00
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12-08-22 04:08 PM - Post#2851069
In response to Fortec Five
Only one similar has come my way. A Terrain had both VVT solenoids stuck. The solenoids would not click when powered with 12V. It's worth checking them out. Both are easy to remove and at least clean
'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE
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gchemist
Member #271 Senior Chevytalk Moderator
Posts: 25841
Loc: Austin, TX 78748
Reg: 05-09-00
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12-09-22 05:07 AM - Post#2851087
In response to gchemist
Another item to check with a mechanic stethoscope, the high pressure fuel pump. It's known tick too. The timing chain guides are known to wear out too. The valve cover can be removed to check the top guides. GM ECM monitor for oil changes was programmed to high. In real life, it should be lower. Like the 3.6L, later models had software revisions to lower oil life service miles.
'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE
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paulo57509
Senior Member
Posts: 567
Loc: CA
Reg: 07-18-00
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12-10-22 09:01 PM - Post#2851142
In response to Fortec Five
ATF has no business in an engine crankcase.
From personal experience, if it is the valve train, HDEO works but it takes a l-o-n-g time to do so.
The best course of action is to find out why it's making this noise. It could be as simple as a crap oil filter.
1987 IROC-Z 5.0L
1992 Lumina Euro 3.1L
2003 GMC Safari |
Edited by paulo57509 on 12-10-22 09:01 PM. Reason for edit: No reason given.
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Tony1963
Frequent Contributor
Posts: 1851
Loc: Orlando Florida
Reg: 07-09-18
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12-19-22 12:41 PM - Post#2851454
In response to paulo57509
All of the magic juice in the world won't fix gummed up or worn parts.
I've had near zero success on engines that had lots of carbon and sludge, other than to pressure wash the crap out of it and such.
| People fear change because it threatens what they know, or what they claim to know. |
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KShortell
Member #1510 Senior Member
Posts: 4084
Loc: Chesapeake, VA, U.S.A.
Reg: 04-14-01
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01-11-23 06:13 AM - Post#2853323
In response to Fortec Five
A knocking on warmup can come from a variety of sources - lifters still pumping up, piston slap, etc.
In the case of my '98 Wrangler, it was the piston skirt coming apart. It got loud and constant when the skirt broke off. After an engine rebuild, she's as good as new!
Good luck! Just remember, a mechanic's stethoscope is your friend here... 
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