[Marriahs]

This post is about my 2007 Chevrolet Colorado 3.7 L

truck has 334,000 km on it I was towing a trailer that’s 3900 pounds, pretty sure This truck has a towing capacity of 6000 pounds but maybe because of the excessive kilometers. Anyway I was driving about six hours yesterday I stopped in the evening and it was pouring rain all of a sudden. So my engine went from hot to cold. It was driving perfectly fine that night, then when I went to start it in the morning, sounded spudderyy and miss firing and felt like really low Engine pressure. I was able to drive it about an hour to an automotive shop. They had a code for the mass airflow sensor so they diagnose that tried installing a new one but it was still miss firing and having issues. Then they looked at a few other things and did a compression test on cylinder want to see if the valve was working. After they looked at that they said they think the valve has dropped down.
I don’t know what to do they quoted me $5000 for a new engine replacement or they said getting the valve replaced would be even more money probably because they’ll need to take out the engine to do it.

I just looked at some YouTube videos of guys fishing out the valve that fell down with a tiny magnet he shrunk onto an electric wire it looked quite stable and able to pull it out do you guys think this is possible or this guys a Houdini? I really need some help I barely have any money I just spent tons of money fixing my brakes and wheelbearings please help me.

Also I should note I had to drive home that day because they couldn’t further help me I drove another hour and a half with this apparent drop valve. If it is a dropped valve, would they know For sure by looking at it? or should I go to another mechanic to get them to also double check?

Thank you so much everyone!!!

 

[16WhiteColly]

For quick help, please visit the 355nation forums, because the entire site is almost dedicated to 1st generation trucks like yours. They will help you better. Hope this helps.

 

[snowwy66]

I'd think if the valve dropped. There'd be some noise when it happened.

You didn't say what the compression was for the cylinder? I'm guessing zero?

 

[16WhiteColly]

I doubt that the truck could be driven for an hour after a valve dropped. If so, there has to be much engine damage.

 

[.boB]

A dropped valve can cause immediate catastrophic damage.

Sometimes, a valve can get hung up, and just kiss the piston. Then the valve gets bent, and won't seal. Then you're running on 4 cylinders.

Fortunately, it's fairly easy to diagnose. Pull the valve cover off, and remove the rocker arms. The tips of the valve stems should all be at about the same height; within 1-2mm. If you've dropped a valve, one (or two) of them will be significantly lower than the rest. If that has happened, the head needs to be rebuilt/replaced.

As in the picture above, there is a possibility of piston damage. The new endoscopes on the market are small enough to fit through the spark plug hole, and should get you a good picture of the piston top. Pay particular attention to the outside edges.

If the piston is damaged, it needs to be replaced. You'll save money on parts by simply replacing the broken bits. But it will cost you a ton in labor. You'll be time and money ahead by replacing the whole engine. Or cutting your losses and buying a newer truck.

 

[White016]

This post is about my 2007 Chevrolet Colorado 3.7 L

truck has 334,000 km on it I was towing a trailer that’s 3900 pounds, pretty sure This truck has a towing capacity of 6000 pounds but maybe because of the excessive kilometers. Anyway I was driving about six hours yesterday I stopped in the evening and it was pouring rain all of a sudden. So my engine went from hot to cold. It was driving perfectly fine that night, then when I went to start it in the morning, sounded spudderyy and miss firing and felt like really low Engine pressure. I was able to drive it about an hour to an automotive shop. They had a code for the mass airflow sensor so they diagnose that tried installing a new one but it was still miss firing and having issues. Then they looked at a few other things and did a compression test on cylinder want to see if the valve was working. After they looked at that they said they think the valve has dropped down.
I don’t know what to do they quoted me $5000 for a new engine replacement or they said getting the valve replaced would be even more money probably because they’ll need to take out the engine to do it.

I just looked at some YouTube videos of guys fishing out the valve that fell down with a tiny magnet he shrunk onto an electric wire it looked quite stable and able to pull it out do you guys think this is possible or this guys a Houdini? I really need some help I barely have any money I just spent tons of money fixing my brakes and wheelbearings please help me.

Also I should note I had to drive home that day because they couldn’t further help me I drove another hour and a half with this apparent drop valve. If it is a dropped valve, would they know For sure by looking at it? or should I go to another mechanic to get them to also double check?

Thank you so much everyone!!!

If it had a dropped valve it would at very least make ticking noises. If it doesn't make noise then it could be a lot of things, some of them simple, some not.
I'm guessing they thought valve because no compression? You didn't say but is one cylinder dead? (no compression)? If so you are looking at at least a bad valve. (exspensive)
You will need to take it to a mechanic no matter what to get it properly diagnosed and a bid to fix it.
Then you get to decide if it is worth fixing.
Good luck.

 

[hyperv6]

I would have to guess a valve is stuck or hung open a small amount. Or a spring is broken to not let the valve seal.

If you dropped a valve You would have known by the noise and odds are you would not have driven it home. They can stick a scope into the cylinder and see what is there. Check the compression and see if you have zero. If a valve was open it would also pop into the intake if an intake valve or exhaust if the exhaust valve is damaged.

 

[DoctorDiesel]

This is he problem with “techs” today. They hookup a computer and do as it says. While OBD has come a lonnnngggg way from its humble beginnings (I still have OBD I jumpers) it still won’t tell you what to replace. You e got to be a diagnostian as well not a parts hanger. A dropped valve causes massive engine damage in almost every case. If the valve gets hung up or a bent stem, cam or timing system damage will likely occurs along with associated parts. They need to pull the valve cover and actually look. Or, better yet, pop out the spark plugs, slide in a borescope and take a peak. Internal damage will show up pretty quick and it can be done fairly quickly. If the bottom end survived, a head rebuild or new head is a helluva lot cheaper than a new damn engine but you’ll have to poke around and put two and two together and not replace whatever is throwing a code at you.

 

[snowwy66]

Putting a new or rebuilt head on a high mile engine usually isn't a good call.

Kind of like replacing a head gasket on a motor that had coolant in the oil.

Could be a gamble.