Timing Belt

[LIONS6]

I have a 98 LS400 98K. Is there a timing belt or chain?

[SRK]

It's a belt - with a 100k mile or 156k kilometer replacement interval.

[raymsixsix]

Hey Lion, yours has a timing belt that should be changed @ 90k miles according to Lexus. If you have a mechanic that will do the labor, you can buy OEM parts on ebay, have them install them, and save some $$$. Welcome to the club

[LIONS6]

It's a belt - with a 100k mile or 156k kilometer replacement interval.

THX!

[IS400]

Hey Lion, yours has a timing belt that should be changed @ 90k miles according to Lexus. If you have a mechanic that will do the labor, you can buy OEM parts on ebay, have them install them, and save some $$$. Welcome to the club

Hey guys.

I just put my lexus in storage for the winter and wanted to do some maintenance items, like plug wires, timing belt, water pump and starter contacts. I was told to adjust the valves also. Sounds a bit tough without experience to me.

What should I be paying for a water pump on e-bay?

The car had regular service by the previous owner at lexus right up until 144,000 miles when it was sold.

The timing belt was listed as replaced at 60,000 miles, but the tech could not find another time it was replaced but admitted his computer was having trouble pulling up all the screens. Do you think it likely it was changed again after the 60,000 mile mark if the schedule was followed by the dealer?

Thanks for any ideas or suggestions for my engine teardown over the next month of weekends.

[SRK]

Here's my take on the engine. It sounds like it is due for a belt. At that time one can inspect the pump and determine if it should be replaced, and if so, it should be a Lexus pump, not the aftermarket ones. Idlers can be checked too. The interval for the Vvti engine is longer - for the early engines it's 60k miles or 98k kilometres.

The ignition wires can be checked on an old-school oscilloscope if need be - if they pass, leave them alone.

The starter contacts can only be accessed after removing the starter, and to do that, the intake manifold has to be removed. The contacts give some warning before failing completely, so I wouldn't be in a hurry to do them until that time.

Lexus checks the valve adjustment by simply listening to them. If they are quiet, then leave them alone. They are a shim adjust type, and unless they become noisy they are fine. These engines wear very little.

It is quite amazing just how little work these cars need to keep them running like new.

[1990LS400]

Here's my take on the engine. It sounds like it is due for a belt. At that time one can inspect the pump and determine if it should be replaced, and if so, it should be a Lexus pump, not the aftermarket ones. Idlers can be checked too. The interval for the Vvti engine is longer - for the early engines it's 60k miles or 98k kilometres.

The ignition wires can be checked on an old-school oscilloscope if need be - if they pass, leave them alone.

The starter contacts can only be accessed after removing the starter, and to do that, the intake manifold has to be removed. The contacts give some warning before failing completely, so I wouldn't be in a hurry to do them until that time.

Lexus checks the valve adjustment by simply listening to them. If they are quiet, then leave them alone. They are a shim adjust type, and unless they become noisy they are fine. These engines wear very little.

It is quite amazing just how little work these cars need to keep them running like new.

I absolutely agree with everything that SRK says with one small amendment ...

I am fairly certain that the timing belt change interval for all U.S. market LS400 models is 90,000 miles or six years. The recommended change interval for SRK's Canadian market models could be a little different. Do you have the maintenance manual that came with your car? It probably tells you the timing belt change interval. The great thing about the belt on the 90 LS400 is that no damage is caused if it should break. If you don't mind having to call a tow truck when it finally (if ever) breaks, you can drive your 90 LS until it does. The bigger problem on the gen 1 LS is the water pump. The water pump on the 90 LS I used to have failed at around 75,000 miles and took the timing belt with it when it seized up. Supposedly the water pump was replaced with one of an improved design but I had the water pump (and timing belt) replaced again at 180,000 miles shortly before I sold the car to a coworker.

If you ever smell coolant, your water pump may be leaking which means that its failure is going to happen very soon. If this happens, you might as well drive directly to your favorite Lexus or indie repair shop and save yourself the trouble of getting stranded.

[IS400]

I have smelled coolant before and noticed small puddles under the car after a hard run. I found an ebay seller that has a kit with the pump and belt and gaskets for $215 plus shipping. Based on the design of the pump, it will wear out no matter the manufacturer IMO.

Plug wires. Test with a clamp on ohm meter is what you mean? What should they read for resistance?

Ordering the kit tomorrow morning unless you boys tell me it is rubbish.

I'm not going to spend $1,500 on a 200,000 mile car at the lexus dealership when I can turn wrenches myself.

Just got done doing the lower ball joints. If I didn't have strong legs, those lower bolts would have NEVER come off!

Thanks for all your replies!

[landar]

The ignition wires can be checked on an old-school oscilloscope if need be - if they pass, leave them alone.

SRK, I would love to know how to check the ignition wires with an "old-school" O-scope. Can you enlighten us?

[SRK]

The old scopes have an inductive pick-up for both the coil to distributor wire and for the number one ( or whichever you want) spark plug wire. The scope then traces the voltages over time, and show the firing and spark lines, as well as the coil oscillations as the voltage decays. The line can reveal a large plug gap, worn plugs, and the condition of the individual ignition wires, and reveal which of the four is at fault, if any. The pick-ups can then be tranferred to the other coil and those four wires checked in turn. It won't work on the later coil on plug Vvti engines of course.

I grew up using them, and they are a very fast way to confirm both primary and secondary ignition performance, without having to just swap in new parts.

[pishta]

The old scopes have an inductive pick-up for both the coil to distributor wire and for the number one ( or whichever you want) spark plug wire. The scope then traces the voltages over time, and show the firing and spark lines, as well as the coil oscillations as the voltage decays. The line can reveal a large plug gap, worn plugs, and the condition of the individual ignition wires, and reveal which of the four is at fault, if any. The pick-ups can then be tranferred to the other coil and those four wires checked in turn. It won't work on the later coil on plug Vvti engines of course.

I grew up using them, and they are a very fast way to confirm both primary and secondary ignition performance, without having to just swap in new parts.

You can check plug wires the really old fashioned way by just using an ohmeter, specs are in the DIY plug section. Before you start checking plugs, I would take the covers off and start the car in a completely dark garage and check for any arcing from the plug wires, then air out and pull each plug wire and Ohm it out. Mine were all within specs after 96k and 15 years. Platinum plugs were OEM with a gap of .044, never gap a platinum plug.