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  #21  
Old 12 September 2010, 09:48 PM
clarkperez2334
 
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Quote:
Originally posted by: robertplattbell

And that is good logic. The secret to keeping a car running and RELIABLE is to understand that certain parts have a certain design life, and if you can replace those parts before they fail, you will spend less time dating tow-truck drivers.

Water pump seals fail over time, and the coolant will leak out in to the bearings. This can cause the bearings to corrode, the pump to wobble, and eventually fail. Sometimes the wobble is enough to cause the fan to throw its plastic blades, sometimes literally through the hood. Other times, they merely take out the radiator (See, e.g., BMW Z3 forum on roadfly.com)

The cost of labor usually trumps the cost of parts. While $130 seems like a lot of money for a water pump (and it is, you are getting ripped off) most shops charge $50, $75, or even $100 a hour for labor alone.

Thus, when you take something apart, it makes sense to renew associated parts, rather than put them back in, if they are about the vintage where they will shortly fail.

For example, when you replace a clutch, you replace the throwout bearing as well. Why? It is a cheap part, and pulling the transmission on a car is a lot of labor. Doing it twice makes no sense at all.

I bought an old Fiat from a guy once (nice car, no rust, one of the later fuel-injected models). He got frustrated with the car, but it was largely his own fault.

A lower ball joint went bad (typical of a 100,000 mile car) and he had it replaced. The mechanic suggested replacing all four ball joints and the tie rods. The fellow said "No thanks! You are just trying to rip me off!" So several hundred dollars later, he has one new ball joint.

Then another ball joint fails. He takes it back, and spends hundreds more, and the mechanic says "I told you so!". Ball joints for that car were $30 apiece. For an extra $150 he could have saved nearly $1000 in labor.

Of course I ended up taking apart the front suspension and replacing all the wear components - bushings, ball joints, tie rod ends, shocks, springs, etc. I think the parts cost was like $300 and the hardest part was jacking up the car.

People who are not car-wise often defeat themselves this way. They don't understand cars, so they don't trust the mechanic, and assume every repair suggestion is a total rip-off.

When repairing a car, think of it in terms of sub-systems, not individual parts. Rather than replace a radiator, replace the entire cooling system. Why? Because the parts cost is not that great, but the labor of replacing each individual part is staggering, if done separately, one at a time, over and over again. Also, once you refresh the entire system, the car is reliable and you don't have to worry about "the next thing" going bad.

And parts are cheap. Like I said, $130 for a water pump is staggering, considering a water pump for a BMW can be had for about $40. I'd find a new mechanic.

Even an old car (13 years old) can be kept in like-new condition this way.

By the way, flushing the cooling system and refilling it with the properly specified coolant and distilled water (50/50 mix) every 2-3 years will help the cooling system last longer. See your owners manual. And avoid Dexcool at all costs!
Nice thoughts here! I definitely agree! we should replace those parts before they fail to avoid "the next part" going bad.
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  #22  
Old 15 February 2011, 02:34 PM
Quidam
 
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Since we're talking about timing belt life, there's a strange anomaly on recommended replacement intervals. In most of the US the interval is commonly 60K miles. In California it's 105K miles. No they don't make better timing belts for California, they do have laws that auto manufacturers cannot require a major service before 100K miles, so they just change the schedule. Clearly the 60K interval isn't that important.

It's worth finding out if you have an interference engine to know if you can risk it breaking. My last three cars are Subarus which have free running engines, I have driven them for well over 200K miles (in around 10 years) on the original belts with no problems. My philosophy is to leave it alone unless there is a reason to replace it - oil leaks or noisy tensioners/idlers. However the age is probably more important than the miles, replacing after 10 years is a good idea - providing the vehicle still has sufficient value...
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  #23  
Old 25 April 2011, 02:12 PM
dave748 dave748 is offline
 
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Quote:
Originally Posted by Quidam View Post
Since we're talking about timing belt life, there's a strange anomaly on recommended replacement intervals. In most of the US the interval is commonly 60K miles. In California it's 105K miles. No they don't make better timing belts for California, they do have laws that auto manufacturers cannot require a major service before 100K miles, so they just change the schedule. Clearly the 60K interval isn't that important.

It's worth finding out if you have an interference engine to know if you can risk it breaking. My last three cars are Subarus which have free running engines, I have driven them for well over 200K miles (in around 10 years) on the original belts with no problems. My philosophy is to leave it alone unless there is a reason to replace it - oil leaks or noisy tensioners/idlers. However the age is probably more important than the miles, replacing after 10 years is a good idea - providing the vehicle still has sufficient value...
Yep, leave it alone until it breaks. Then while you're replacing the belt, you can replace the valves that have hit the pistons, as well as the pistons that were hit by the valves. This is assuming that no other damage has been done. Worst case scenario, you'll have to replace the engine as it will be cheaper than repairing the damage to the old engine. A work collegue went past his recommended belt change interval by 7,000 kms because of budgetry constraints but then had to rebuild the engine when the timing belt failed. It's not just belt failure that can cause this damage but also timing chain failure in earlier models from the 50-80's etc. It was just rarer as the chain would give a lot of signals prior to failure as well as going a lot further before failure. The manufacturers give a life for a reason, and it's not to make money. No manufacturer wants to get a name of unreliability due to part failures, it will hurt future sales, so it is in theirs, and your best interests to replace parts when recomended.
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  #24  
Old 25 April 2011, 02:27 PM
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GenYus234 GenYus234 is offline
 
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Did you miss the part where Quidam said to find out if it was an interference or free-running engine? Because a broken timing belt won't cause any damage in a free-running engine, only in an interference engine.

Of course, a broken timing belt will leave you stranded, waiting for a tow truck either way.
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  #25  
Old 25 April 2011, 02:41 PM
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AnglRdr AnglRdr is offline
 
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This thread needs a more zombie-fied background.
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  #26  
Old 25 April 2011, 03:30 PM
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BoKu BoKu is offline
 
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Quote:
Originally Posted by Quidam View Post
...My last three cars are Subarus which have free running engines...
Some but not all Subaru motors are non-interference. In general, all of the DOHC motors are interference. So if you look at the plastic cover on the front of the engine and it is shaped to cover two pulleys each on the right and left sides of the engine, it is an interference engine.

From Wikipedia:

Quote:
The SOHC EJ Subaru boxer engines were non-interference engines through 1996, run by a single timing belt driving both cams (both sides of the engine) and the water pump. Because they are non-interference engines, if the timing belt fails, the engine of the models up to 1996 will not be destroyed. The oil pump is driven directly from the crank shaft and the waterpump by the timing belt. All DOHC and 1997-up SOHC EJ engines are interference engines, if the timing belt fails the engine will likely be destroyed or the valves & piston will be heavily damaged.
Thanks, Bob K.
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  #27  
Old 10 June 2011, 09:33 AM
Roadhog
 
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Some engines dont even use a timing or cam belt.
Morris, Austin, BMC and Nissan cars all use chains. These last considerably longer and slack is contained by tensionners, often for decades.
The chain, similar to a bicycle chain can in some cases act to operate other internal parts that the belts used on other cars dont operate. Replacement dosen't usually require serious internal repair or re-setting the timing, as the chains are generally fitted to match the related gear ratios.
A warn belt gives little, if any warning of breaking, whereas a chain can make the engine sound like a machine gun for upwards of 10,000 miles before any serious damage occurs!
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