CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Timing belt broke - repair or buy car?

The timing belt broke on my 2000 Plymouth Neon. As I understand it there is possibility that in breaking the timing belt may have damaged some of the valves in the engine. The engine damage cannot be assessed until the timing belt is replaced. A belt repair would cost $300. If the engine is damaged, repairing it could cost $2,000 to $3,000 by rough estimates.

How likely is it that the valves have been damaged?

More back story:
Last week I brought the car into my local trusted mechanic for a repair, because I heard a belt making a noise. I was told that both the a/c and alternator belts needed repairs, and I had new front tires put on because they were wearing down. Last evening the car stopped running while diving on the interstate. After costing over to the shoulder and waiting for 1.5 hours in 90 degree heat for a tow truck, I had the car towed back to the repair shop and dropped the keys through the overnigh slot. I figured the alternator belt broke and was either faulty or improperly installed, so I trusted the mechanic to repair it for free. It turns out that the timing belt broke, and this is a repair not performed by this shop. (They focus on tires, oil, breaks, a/c, and other more moderate repairs). Because they do not work on timing belts and it is not easily visible, they never inspected it when replacing the other belts. This was something I was not aware of; I figured all the belts were in good condition after last weeks repairs. As I mentioned previously, repairs could cost $300 to $3,000, depending on the severity of the damage. If the belt did not break and possible damage the engine, the car would be worth about $1,400 tade-in or $3,000 dealer retail. Thus for the potential cost of the $3,000 repair, I could be the exact same make, model, and mileage (91,000 miles) car. However if I were to buy another car, I would probably buy an newer used car for around $10,000 to $15,000.

Is it worth $300 to see if the engine is damaged and needs additional more costly repairs?

Is it worth paying for repairs that equal the used purchase price of the vehicle?

I would appreciate thougtful opinions the aid me in this stressful time.

Thank you

Just to be clear, the repair estimates are from shops other than the initial shop.

The engine on this car–Chrysler’s 2 liter 4 cylinder–IS an interference engine.
As a result, it is not a question of whether there is internal engine damage, and the only questions are…how many valves are bent, and…were any of the piston tops damaged by colliding with the valves? In other word…just how badly was the engine damaged when the belt broke?

Most likely, the $2k estimate is pretty accurate.

Personally, I can’t see putting a few thousand $$ into a car that is at least 12 years old, and I would recommend that you put that money into a newer car.

If your next car has a timing belt, please bear in mind that you could wind up in the same situation again if you don’t do preventive maintenance. That Neon needed to have its timing belt replaced ~every 5 yrs/60k miles, but a newer car would more typically have a 7 year/105k mile replacement schedule for the timing belt.

When you buy a used car, unless you have documentary proof of the timing belt having been changed on schedule, you have to assume that it has not been done, and you need to have it done a.s.a.p. Don’t take anyone’s word for this type of maintenance. Only believe hard copies of invoices.

But–whatever the timing belt replacement schedule on your next car might be, if you don’t abide by it, the result can be thousands of $$ in repairs.

This being an interference engine, there is a very high likelihood that there are bent valves, but there are other, much simpler ways to determine if there is valve damage. Your mechanic could simply remove the valve cover and inspect the valve lash. Excessive valve lash indicates bent valves. Inspecting the valve lash should take about 15 minutes and you would have your answer.

I also agree that it is necessary to be proactive with this maintenance item on your next car (or this car if you choose to fix it). You should not assume that your mechanic will automatically replace your timing belt when he/she does other work. A timing belt is a rather involved, time consuming job, and some mechanics are hesitant to perform this work or even try to suggest it, either because they don’t want to do the work or don’t want to be accused of trying to rip someone off for a multi-hundred dollar belt replacement. Also, inspecting the belt is not an accurate way to determine if it needs to be replaced. They can look as good as new during the inspection, then break on the way home from the shop. The only way an inspection can be of value is if the date code from when the belt was manufactured can be seen, which many times it cannot be seen or has worn off.

I will not add anything except to agree that you should not spend money replacing a belt to determine if engine damage exists. That is a horrible way to go about diagnosing a problem like this and mark9207 pointed out a very good method.

Another method would be to line the camshaft sprocket up in a position where the valves are both closed on a particular cylinder, remove the spark plug, and apply compressed air. If air hisses back out the intake manifold then the intake valve is bent. (Intakes usually bend because the valve head is larger.)

The timing belt on many cars isn’t clearly visible without removing a few access parts. I guess I’d want to know for certain that the timing belt in fact did break, and wasn’t simply a little ravelled. And if it did in fact break,I’d want to know whether or not something was damaged and the cylinder head needed to be reworked. I’d be inclined to spend a hundred dollars or so for that info. If it in fact your car needs a head-job, and assuming you like this car otherwise and it has been reasonably reliable for you, then I’d price out what it would cost to change out the engine for a rebuilt one. That’s the basic info you need to make the decision. You might be surprised how economical it is to simply swap out the engine.

What if it were my car? hmmm …Neon? 2000 model? … you didn’t say how many miles, but probably 120-160K … hmmm … well … If a new engine was required, I wouldn’t spend the dough. I’d see if I could sell or donate the car to a local high school or college that had car repair training. They could take it apart and learn from it. They’d probably rebuild the engine and sell it to fund tool purchases. Seems like a good cause. Besides, I wouldn’t want to own a car that was so sensitive to a simple broken rubber belt. I’d buy a newer used car instead , and I’d make sure to buy a car w/a non-interference engine.

Car owners have developed a rather dim view of timing belts (you can understand why). Your next car will probably have a timing CHAIN or at least a non-interference engine…

Move on, the likely repair far exceeds the value of the car.It is not a desirable easy sell in the market running.

Rarely do interference motors not cause serious damage when a failed timing belt is involved.

Last time I checked on car-parts.com, there were a lot of used engines for sale on this car. The prices were ~$300, so if the labor of putting one in could be kept down, I will consider a junkyard engine with a 6 month warranty.

Thank you for your opinions and suggestions.

I am looking into assessing the valves without replacing the timing belt as made in a couple of suggestions. However I have also started online shopping for another car in the likely hood that he engine will need to be repaired/replaced. I did get 10 very good years out of the car from an initial purchase price of $8,000 used.

Though I had been trying to keep the car well maintained, I was never following any scheduled maintenance manual. The car did not have it when I bought it. However, I have learned my lesson, and I’ll find the manual online if the car does not have one.