Did you blow an engine in your SC 430 ? If you did, what happened, what was the cause ?

I'm hoping to gather statistics on engine failures in the SC430 engine, however rare they are.

 

i was just going to laugh at you (but also provide some tips)
but for some reason, seeing how youre from ireland, i just want to help you aha

keep up on the maintenance is the number one thing.
constantly check the oil level and change the oil/filter at regular intervals.
this will ensure everything gets lubricated. lack of lubrication equals to friction/heat
which will cause spun bearings, etc which will require a teardown and rebuild.

keep an eye on the temp gauge as well as sure there is always sufficient coolant within
the system so that the car doesnt overheat and lend to a blown headgasket.

 

Change your timing belt at the required yearly or mileage intervals. The yearly interval for the 2006 SC430 is nine years, while the mileage interval is 90k. I'm not sure how much the belt would actually show wear before failing or breaking. If it looks brand new when changing it, so be it, it's the right thing to do and could potentially save you from a blown engine. Lastly, while changing it, since the engine is partially disassembled, it is recommended to also change the water pump, pulleys, etc. OEM kits are sold on Ebay.

Timing belt failure on an interference engine:

In interference engine designs, regular belt service is especially important as incorrect timing may result in the pistons and valves colliding and causing extensive engine damage and therefore costly repairs. The piston will likely bend the valves or if a piece of valve or piston is broken off within the cylinder, the broken piece may cause severe damage within the cylinder, possibly affecting the connecting rods. Many manufacturers who were using belts for valve timing have gone back to using chains on new engine offerings, especially on interference designs. However, some non-interference designs have retained belts due to the risk of engine damage from a belt failure being minimal. Some manufacturers liked the belt's quietness compared to the chain. However, chains, in many cases, last the life of the engine, rarely requiring maintenance. Also, it was discovered that the sound difference between the two was negligible. During the peak popularity of the belt, chains or cogwheels were used almost exclusively on overhead valve (OHV) engines (which rarely are equipped with belts, regardless of the manufacturer and time of design) and almost all overhead camshaft (OHC) engines received belts. However, chains are lately becoming more popular for OHC designs.

 

Thank you for your condescension. Your input to this discussion is greatly valued......

Gentlemen, I am just hoping to gather statistics on who blew an engine and why. There is a few members who have mentioned it, but no single source of stats available on the forum about it

How to maintain an engine or a car is not an issue for me considering I'm a fully qualified car mechanic and a licensed B1 aircraft engineer on Airbus and Boeing aircraft. I'm doing my own timing belt and all the rollers and water pump, front end oil seals inc power steering pump next week, for example....and thanks for the tip on this, SixOneMale.
The issue for me is to gather information to know where to focus my efforts to preventatively fix problems that have caused others serious problems, and I find this forum very good for that, especially the old Soarer / SC300 section and the GS 300- 430 sections too. Anyway, I digress.

 

sixonemale, I agree that you should change the timing belt when prescribed and address everything else that makes sence while you have access. You seem to be implying that the SC430 engine has an "interference design". Can you or anyone else confirm that the SC430 engine does indeed have an interference design that will likely sustain significant damage if the belt fails?

 

It does. I wrote Lexus a few years ago. They confirmed it.

 

VVTiBob who is a forum moderator said it is in this link:

https://www.clublexus.com/forums/sc-...nce-motor.html

Plus I have also seen it in other sources, that the SC430 engine is an interference engine. Additionally a member sometime ago had his timing belt fail which caused catastrophic damage to his engine. More specifically, when the timing belt broke he had to make a decision on whether to replace the engine or sell the car as is with a blown engine. If you do a search you should be able to find this link.

 

I too would be curious to hear about engine failure, including that related to plain lack of maintenance.

My experience over the years with Lexus and other Toyota products is that if properly maintained they seem to run forever with few repairs. The first Lexus, the inaugural LS400 was purposefully over-engineered as Toyota risked a lot when they first entered the luxury market. It is still considered one of the most reliably built cars in history.

But from my personal experience driving Lexus and Toyotas (as well as Nissan and Mazda), the Japanese, in general, take a very high level of pride in reliability and design longevity into each part. I also own an 8 cylinder BMW and can tell you the Germans have no such similar pride when it comes to reliability. The list of what has gone wrong with my BMW is as long as my arm. But it does drive like a roller coaster on rails.

The 4.3L SC430 engine is indeed an interference engine. But I have never heard of an account of a failure of a belt itself. It is always a seized water pump or belt tensioner that fails and takes the timing belt out. Because the belt is relatively inexpensive and must be removed to change out the water pump and tensioner all three are changed at once given the labor required to get to them (they are commonly sold bundled in a kit). Refresh the coolant every three to four years to keep the water pump well lubricated.

My 2002 SC430 just turned 96K miles and runs like a champ. M1 0W-40 every 5K miles keeps it that way.

 

I replaced my timing belt at 149K miles w an OEM unit. It was the original belt but it looked like it could go another 50K easily, no cracks whatsoever.

 

Good question. Hopefully you can get some first hand responses.

My guess is that the results might be a bit skewed. Most all of the SC430 forum members are interested in their cars and proudly maintain them.

I've been on this forum since 2012 and only remember a few blown engine posts, some from second hand info. As mentioned above these engines are very solid and if you follow the recommended maintenance schedule, should last a very long time.

The one problem area I have noticed is the radiator. There is no planned interval for replacement, just visual checks and coolant replacements. This item does fail and a quick loss of coolant can be disastrous. I decided to replace my radiator along with the main hoses and thermostat and found a small leak at the bottom which was undetectable during a normal visual inspection. Seems to me that at 10 years or 120,000 miles this should be a normal replacement item. Parts, including hoses and antifreeze are around $150 and it is a fairly easy back yard mechanic job.

 

This thread was from 2013...

 

A shop I was in was replacing a sc430 motor with a bone yard engine.

they said the engines temp sensor was on the radiator and when it leaked the motor got too hot quickly and it failed.

 

​​​​​​The sensor not on the radiator but it is true is that overheating will destroy an engine. Or at least blow the head gaskets. The temp sensor is on top the engine near the throttle body. Should be replaced around 100k. It is also not the same as sensor that runs the guage.

 

Just got my car back today after getting a heart transplant, 2002 SC. The failure was the radiator...unfortunately it blew out on the way home from work on day and I wasn't getting a temperature reading nor was seeing any steam to even cause me to look at the temps. Got off the interstate and it just seized up.

 

Oh bummer. Sorry to see that. Seems like I remember another member who had the same problem a few years ago. Definitely worth checking the radiator occasionally for seepage.

What are the specs on the replacement engine?