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Neal, Chevy Mechanic
Category: Chevy
Satisfied Customers: 8351
Experience:  Shop Owner and Mechanic on multiple makes.
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chevy colorado: runs warms up it sounds..diesel..valve cover

Resolved Question:

am working on a 05 chevy colorado and it runs great no miss no codes but when it warms up it sounds just like a diesel no miss no codes but you would think you were standing by z isuzu npr- 66K miles and sounds like itcoming from passiger side so i took valve cover off but nothing looked bad all rollers and rockers look good i am at a loss and am wondering if you all have seen anything like this before
Submitted: 5 years ago.
Category: Chevy
Expert:  Neal replied 5 years ago.

I'm Neal and I am here to assist you. Only accept when you are happy with my assistance. If I can't help I will open your Question to other experts.


Most likely it is going to be the cam and lifters, they are known to fail in those.

Customer: replied 5 years ago.
why does it run so well and then when it gets hot this happens wouldnt lifters give a miss and set a code/s exhaust cam looks the same as the intake cam
Expert:  Neal replied 5 years ago.
The lifters can make a lot of noise before they cause any other symptoms and you might just need to replace the lifters if the cams look good. But check everything closely while it is apart of course.
Customer: replied 5 years ago.

these lifters are rollers on the cam not hydraulic wouldnt i be able to spot one visually


Expert:  Neal replied 5 years ago.

Not really. Sometimes you don't find the problem until it is apart.


But I am going from your description that it is coming from the valve train.

Customer: replied 5 years ago.
most definetly on the top i killed each plug and it had no change to the sounds like rist pin or piston skirts what freaks me out is that if i let it cool down and start it up it runs beautiful but as it closes to operating temp it gets louder and louder tiull it sound like a diesel is in it
Expert:  Neal replied 5 years ago.
I assume the oil pressure is good? And it is not dropping when it warms up?
Customer: replied 5 years ago.

sorry to drop ya but had to do something "more important"?

my question was had you heard of this before going from absolute running fine to sounding like a diesel no miss no codes just racket that sounds like an isuzu customer walked in from behind and wondered if we worked on diesels too! i have not found anyone who has come across this prob with this motor so i will start from scratch and see what comesof it thanks for the help anyway

Expert:  Neal replied 5 years ago.
You're welcome, good luck with it!!!
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