Lexus SC400 Timing Belt
Posted: Sun Feb 23, 2014 9:18 pm
Finally uploading pics of this.
There is no replacement interval for the timing belt on a 1UZ-FE unless it is used as a taxi or other situation where it idles a lot. In that case it is 60K. This car has 125K on it, so double the taxi interval mileage. There was quite a bit of other maintenance this car needed, including a major tune up, so we figured it would be a good time do just do everything all at once since most of the labor overlapped. Also it would make us feel better in case we were hammering on the car later.
In case you were wondering: 1 = first generation, UZ = engine family, F = DOHC, narrow valve angle head, E = electronic fuel injection.
Rock Auto sells a nice kit which includes a belt, a water pump, an idler pulley, a tensioner pulley, and a hydraulic tensioner. They actually have a few different brands, we went for the Gates. In thing engine, like other Japanese engines, the water pump is driven by the timing belt so they are generally replaced at the same time.
Lets start!
This engine is dirty.... Start at the top on the driver's side and remove the ignition wire covers. Also doing valve cover gaskets, so remove the PCV hose and the wire harness cover. You can see the missing valve cover bolt in this shot. Moving the cover also exposes the LH distributor and cam pulley. Yes, this engine has two distributors. For double the awesomeness. To remove the passenger side cover, remove the intake tube. This was a terrible job. In hind sight, if you remove the three bolts that hold in the air box you can lift it up and get the flexible rubber joint off much easier. You can then remove the radiator assembly. This includes the hydraulic (!) cooling fan and overflow bottle. The whole thing comes out as one piece, just disconnect all the hoses from the engine side, two brackets and lift. Make sure you drain the coolant first. I didn't get any shots of the removal, but it wasn't very exciting. You can free up some additional reaching room by removing the battery. After this you can remove the serpentine belt. The belt can be removed earlier, but its even easier with the radiator hoses out of the way. Also remove the serpentine idler pulley. Shot of some pulleys with no belt or hoses. Remove the alternator and loosen the A/C compressor (RH lower and LH lower respectively). Then remove both ignition coils. Next remove the two upper timing cover pieces. There is one on either side. They are held on with a few 10mm bolts. The LH one is a little bit of a pain as the distributor harness feeds through it and is hard to pull back through if the plug bracket is rusted to the plug. If you can get this small bracket off, this is not an issue. LH is driver's side and RH is passenger's side. You can see the water pump pulley now. The timing belt tensioner bolts straight up into the timing belt tensioner pulley on the RH side of the crank pulley. You can reuse these if you apply several hundred pounds of force to the piston to retract it and lock it in with an hex key. We had a new one so that wasn't an issue. Now is the fun part. To take the crank pulley bolt off, you need to hold the pulley stationary. This is normally done with a fancy Lexus/Toyota tool which utilizes two bolt holes in the crank pulley to attach a collar which you bolt a large handle too. I didn't have this, so a fashioned one out of wood and was going to use the weight of the car to pry against (this nut torques on at > 180 lb-ft). This didn't work. I split the wood before I got the nut to break free. You can buy the Lexus/Toyota tool for ~$165 in various places. This seemed expensive, so I ordered a mostly compatible one from eBay for much less. It just requires a large pipe which we have.
OEM Collar
http://www.toolsource.com/prod_medium/99091.jpg
OEM Handle
http://www.toolsource.com/prod_medium/97504a.jpg
Much cheaper eBay Special
http://www.ebay.com/itm/like/251439944179
I also ordered a cam pulley holder tool
http://www.ebay.com/itm/Auto-Car-Univer ... 1455192207
While waiting for the tools to show up, I figured it would be a good time to do the valve cover gaskets and spark tube seals. I pulled the ignition wires and distributor caps off both distributors as one assembly to simplify reinstallation later. The RH valve cover comes right off. You can see the internal gear drive for the exhaust cam here. Also remove the spark plugs. Use a pry bar to pull the old spark plug seals out and a seal installer to put the new ones in. Clean everything off before reinstalling. Clean and ready to reinstall the LH cover. You need to apply a small dab or RTV on each area where there is a metal joint on the cylinder head. There are eight spots in total. Two at each end of each camshaft including where the camshaft protrudes from the head to attach to the cam gear.
There is no replacement interval for the timing belt on a 1UZ-FE unless it is used as a taxi or other situation where it idles a lot. In that case it is 60K. This car has 125K on it, so double the taxi interval mileage. There was quite a bit of other maintenance this car needed, including a major tune up, so we figured it would be a good time do just do everything all at once since most of the labor overlapped. Also it would make us feel better in case we were hammering on the car later.
In case you were wondering: 1 = first generation, UZ = engine family, F = DOHC, narrow valve angle head, E = electronic fuel injection.
Rock Auto sells a nice kit which includes a belt, a water pump, an idler pulley, a tensioner pulley, and a hydraulic tensioner. They actually have a few different brands, we went for the Gates. In thing engine, like other Japanese engines, the water pump is driven by the timing belt so they are generally replaced at the same time.
Lets start!
This engine is dirty.... Start at the top on the driver's side and remove the ignition wire covers. Also doing valve cover gaskets, so remove the PCV hose and the wire harness cover. You can see the missing valve cover bolt in this shot. Moving the cover also exposes the LH distributor and cam pulley. Yes, this engine has two distributors. For double the awesomeness. To remove the passenger side cover, remove the intake tube. This was a terrible job. In hind sight, if you remove the three bolts that hold in the air box you can lift it up and get the flexible rubber joint off much easier. You can then remove the radiator assembly. This includes the hydraulic (!) cooling fan and overflow bottle. The whole thing comes out as one piece, just disconnect all the hoses from the engine side, two brackets and lift. Make sure you drain the coolant first. I didn't get any shots of the removal, but it wasn't very exciting. You can free up some additional reaching room by removing the battery. After this you can remove the serpentine belt. The belt can be removed earlier, but its even easier with the radiator hoses out of the way. Also remove the serpentine idler pulley. Shot of some pulleys with no belt or hoses. Remove the alternator and loosen the A/C compressor (RH lower and LH lower respectively). Then remove both ignition coils. Next remove the two upper timing cover pieces. There is one on either side. They are held on with a few 10mm bolts. The LH one is a little bit of a pain as the distributor harness feeds through it and is hard to pull back through if the plug bracket is rusted to the plug. If you can get this small bracket off, this is not an issue. LH is driver's side and RH is passenger's side. You can see the water pump pulley now. The timing belt tensioner bolts straight up into the timing belt tensioner pulley on the RH side of the crank pulley. You can reuse these if you apply several hundred pounds of force to the piston to retract it and lock it in with an hex key. We had a new one so that wasn't an issue. Now is the fun part. To take the crank pulley bolt off, you need to hold the pulley stationary. This is normally done with a fancy Lexus/Toyota tool which utilizes two bolt holes in the crank pulley to attach a collar which you bolt a large handle too. I didn't have this, so a fashioned one out of wood and was going to use the weight of the car to pry against (this nut torques on at > 180 lb-ft). This didn't work. I split the wood before I got the nut to break free. You can buy the Lexus/Toyota tool for ~$165 in various places. This seemed expensive, so I ordered a mostly compatible one from eBay for much less. It just requires a large pipe which we have.
OEM Collar
http://www.toolsource.com/prod_medium/99091.jpg
OEM Handle
http://www.toolsource.com/prod_medium/97504a.jpg
Much cheaper eBay Special
http://www.ebay.com/itm/like/251439944179
I also ordered a cam pulley holder tool
http://www.ebay.com/itm/Auto-Car-Univer ... 1455192207
While waiting for the tools to show up, I figured it would be a good time to do the valve cover gaskets and spark tube seals. I pulled the ignition wires and distributor caps off both distributors as one assembly to simplify reinstallation later. The RH valve cover comes right off. You can see the internal gear drive for the exhaust cam here. Also remove the spark plugs. Use a pry bar to pull the old spark plug seals out and a seal installer to put the new ones in. Clean everything off before reinstalling. Clean and ready to reinstall the LH cover. You need to apply a small dab or RTV on each area where there is a metal joint on the cylinder head. There are eight spots in total. Two at each end of each camshaft including where the camshaft protrudes from the head to attach to the cam gear.