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No compression in 1 cylinder

Hi everyone,

I have a 2009 Kia Borrego 4x4 SUV with 8 cylinders. Just this week the engine suddenly stop working. I mechanic friend from church did a diagnostic test and told me cylinder 2 has no compression due to the valve spring not shutting. He recommended i take the car to a Kia dealership to have it fixed since he is not comfortable with the engine and brand. He thinks the cost may run between $1700 to $3000 depending on dealer markup and additional diagnostic tests they may run. What advice can you guys give me. I can’t afford a new car at the moment. If I can fix this and run it for another 2-3 years i will be happy. Also please comment on the cost estimate from my mechanic friend. Thanks.

If your mechanic is sure it is the valve, then one of two things. The valve is burned and have to be replaced or there is no valve clearance between the cam and the corresponding lifter (or bucket). If the latter, it may be adjustable if your engine has rocker arms, that would be the cheapest, or shims will need to be removed from the bucket.

If the valve has not been closing for some time, the valve will burn in short order. Depending on circumstances, it can happen in minutes. Then the valve has to be replaced anyways. If the valve spring broke, it can be replaced, but that also leads to a burned valve in literally seconds.

You might check with other independent mechanics that may be willing to tackle this engine. Engines aren’t that much different from one brand to the next. The issue for independent mechanics is access to parts and information.

If the valve spring is broke it can be replaced without removing the cylinder head. The labor guide shows 8 hours labor to replace the valve springs or valve seals on one bank, they may charge less to replace just one valve spring.

For some reason the valve spring replacement procedure on the 4.6L V8 shows the cylinder head being removed. As posted above valve springs can usually be replaced without removing the head. They inject compressed air into the spark plug hole to prevent the valve from dropping into the cylinder during the spring replacement. I’m guessing the job takes less time is you actually remove the head if all the valve springs are being replaced. But for only one spring, head removal probably is not required. I’d guess for one spring, no head removal, maybe 6 hours, so if you ask around you may be able to find somebody to do it for around $600-$750. The spring itself is inexpensive, less than $20. I don’t see a reason to use a dealership for this myself, unless the dealership quotes a competitive price. If I had this problem I’d worry a little why the valve spring broke in the first place. Might be a good idea to make sure that area of the engine is getting enough lubrication before investing in a new spring, as if there’s a lube problem (due to that area being gunked up for example), then the other springs may already be weakened beyond redemption.

! !
! ! < valve spring wraps around this valve stem
! !
------------------------------------------- <— cylinder head above this line, engine block below
! !
VVVV <---- compression seal part of valve

Cylinder

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Can you start another thread or 2? It’s not confusing enough to be challenging yet.

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Hello everyone. I want to give a quick update on the Kia Borrego. I spoke with the local Kia dealer and spoke with the mechanic and tried to explain the condition of the vehicle’s engine. He stated the initial cost for a general diagnostic test would be $99.00 and then most likely, they would need to do additional, specific tests to see if and why any cylinders have no pressure. This could add a coupled hundred or more to the bill. And of course, depending on what needs to be done, the bill could grow into many thousands more up to $6,000.00 for a replacement engine. Since the car has around 185,000 miles and is 10 years old, I have decided it would not be worth it to fix and instead will donate it to a local charity and receive a tax deduction. I will have to just purchase a new or used vehicle.

Thanks again for everyone’s comments and suggestions.

It would be more beneficial to a charity if you just sold it to a scrap yard and gave the funds to the charity. That way they don’t have expenses of moving a damaged vehicle and possible title fees if they apply .

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If any of your local high schools or community colleges have auto repair classes, given the nature of the problem between the way it is now and a running car is likely relatively minor (in relative terms), one of those institutions might be interested in having this car donated to them for their students to work on, fix, and study. Afterward they might decide to sell it for a profit, and use the money to buy more tools and test equipment for the program. It’s a win-win.

Tax laws have changed now with a higher standard deduction. It’s going to be hard to get beyond the standard deduction anymore so yeah, junk it and donate the money or keep it, your choice. Or treat it as a learning experience and pull the heads or valve covers and have a look see.

What I don’t understand is why the SUV, with an 8-cylinder engine, won’t start due to one dead cylinder. I have driven cars with poor compression in one or more cylinders, and they still ran adequately. By “adequately”, I mean they started, did not stall out, did not smoke or burn huge amounts of oil. It sounds to me like a failed timing chain/belt.

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+1. Better diagnosis needed. One valve could not keep the engine from running. It can’t be hard to find out if the camshaft is turning while the engine turns over - on many engines, just take off the oil fill cap and see. This could also be a failed CPS crankshaft position sensor or similar electrical component.

A failed valve would not produce the “engine suddenly stopped working” result.

I think Alex has made up his mind on this 10 year old vehicle with 185000 miles.

Maybe. But a decision made yesterday might still be unsettled today. I can’t be the only one whose mind works like that some times!

Alex might be thoroughly sick of this problem while others here are just getting interested.