The oil pump itself slides over the snout of the crank, and doesnt even need to be touched when doing a timing belt,

It would if he replaced the front seal. It is a good practice to replace any leaking seals to avoid getting oil on the timing belt.

 

The front seal slides into the front of the pump assy. You would have to seriously mess something up to affect it. I cant even think of something that can be done to mess up the operation of the oil pump by installing the seal improperly. Also, for the extremely low price they paid for the tbelt replacement, i very very highly doubt they replaced any seals. They likely just slapped on a tbelt and called it a day.

 

being an intermitteint problem, im going to guess that ever once in a while, at random, the belt is skipping a tooth, either a defective/loose belt, tensioner, or sproket are to blame. BYT, it could also be an oil pump failure, think abotu this.

if the knocking is rod knock, then when you shut off the engine, all of the oil goes back down to the bottom of the engine, where the knock is quieted for a second. then, with the oil pump not working, the upper part of the engine (THE HEADS ) are not getting oil, so the valve knock and lifter knock kicks in, then the motor bogs down becuase the valves/cams have slowed for lack of oil...

my theory here is, the more you run it, the more damage is being done. if the oil pump was shot, as soon as she noticed it, and shut off the engine, had she not restarted it, the motor may have been saved, thats kinda what the light is there for. just because it comes on, doesnt mean a complete motor rebuild, IF you turn off the engine IMMEDIATELY after the light comes on.

 

I have a 95 ES300 with 120K miles on it and it is hard to see the oil on the drip stick between oil changes. I see no signs of slug in this engine. Maybe your car was driven by a grandmother only on the weekend.

Yes , the timing belt may be setup incorrectly but what is up with the oil light? Since the direction of the engine rotation is always the same, it can't slip a tooth then go back to the same place it was at. It would just slip in the same direction and cause the timing to be worse each time it slipped. The result would be no power and backfires.

Here is what I have seen in some European engines with similar problems. This is a engine diagram for the 99 Es300 BTW. The oil pump is driven by the driven rotor…but notice how the drive rotor just extends though the Crankshaft front seal and relies on friction to get its drive. What drives the drive rotor? It is the bolt that holds on the crankshaft pulley. It is a friction fit, so if this bolt is loose, the oil pump isn't driven. And yes, if the bolt is loose, sometime the pump is driven, the next time it is not.

Solution, just take it to another/differnt shop and have the crank bolt torqued to specification. If it is loose, you have and issue with the mechanic who did the repair. Was the engine damaged if this is the case...yup.

 

Oil Pump

 

thats kinda sorta what i was saying, thansk for clarifying. i forgot to add that.

 

Might want to check that the crankshaft bolt isn't bend or stripped. If the shop damaged the bolt during removal and they didn't do the right thing and replace it , it could be the source of your problem.

 

i believe that bolt is Torque-to-yeild, so it has to be replaced, or it will back off.

 

The torque spec I show is 159 Ft/lbs for the crankshaft bolt. It doesn't state that this is a TTY bolt, but any high torque bolt should be replaced to insure the repair lasts.

 

Bro... the oil pump isnt a "friction" drive.... the pump itself is keyed to the crank shaft... there isnt a way for it to slip. The crank bolt could be completely missing and the oil pump will always be driven as long as the crank is moving. I know this from doing so many t-belt jobs, engine rebuilds, tear downs, ect... Ive had a chance to look at it all up close. And what you said, just isnt the case with the oil pump.

 

i dont think this is a tty bolt... and ive never had one back out after setting it to stock torque specs, and ive had hundreds of jobs where that bolt has to be removed....

 

ok, well definately thanks for clarifying THAT LOL. i wouldnt really know sincei have never been ***** deep in a lexus/toyota. but i have had that bolt back off on my dads charger, but again, completely different motor/car.

im not sure now what to make fo this whole thing...

 

I haven’t seen the drive rotor to see if it has a key and the illustration doesn't show it. Anyone that has been this far into the Lexus 300 engine please post a picture. The key would have to go under the main front seal to engage the oil pump and this presents all types of opportunities for oil leaks.

 

This is a picture of an actual Es300 oil pump. We have at least 15 of these in stock . As you can see there are too grove on the pump and it slide into the crank shaft.



JPI

 

my guess at this point, would be a fault oil pump, or a clogged pickup. but it sounds like the engine damage has already been done anyway.