91 Ls400 Oil Pressure?

[md91ls]

LOCAL MECHANIC SAYS PROBLY PICK UP SCREEN CLOGED. CHECKED IT. ITS CLEAN. HE SAYS NOW IT NEEDS OIL PUMP,ONLY 170K MI. WELL MANTAINED. ONLY MINOR ENGINE NOISE AT IDLE. NEED INFO. WHAT SHOULD PRESSURE BE AND HOW TO IMPROVE IT. OIL ADDITIVES,ETC... I HAVE HAD NO PROBLEMS FOR LAST 3YRS. I REALLY DONT THINK ITS THE PUMP. HOW CAN I BE SURE? NEED ADVISE . THANKS GUYS. NEW MEMBER

[SRK]

First, turn off the caps and talk normally.

Second, the pump is in the front cover of the engine, and is driven off the crankshaft. It is very unlikely that it is the pump. More than likely he is hearing the valve noise caused by slightly excessive lash. These engines have mechanical, not hydraulic, valve lash adjustment, and they can clatter a bit.

Lastly, has he installed a master gauge on the oil pressure switch port to confirm low values? I doubt it. Change mechanics, not the pump, if he has not.

[IS400]

First, turn off the caps and talk normally.

Second, the pump is in the front cover of the engine, and is driven off the crankshaft. It is very unlikely that it is the pump. More than likely he is hearing the valve noise caused by slightly excessive lash. These engines have mechanical, not hydraulic, valve lash adjustment, and they can clatter a bit.

Lastly, has he installed a master gauge on the oil pressure switch port to confirm low values? I doubt it. Change mechanics, not the pump, if he has not.

SRK, some people here in the U.S. have bad vision and may feel more comfortable typing in caps. Send him a private message rather than being rude please.

Oh, are you saying these cars have solid lifters or hydraulic lifters? Just want to make sure I PM you the right response SRK.

[SRK]

SRK, some people here in the U.S. have bad vision and may feel more comfortable typing in caps. Send him a private message rather than being rude please.

Oh, are you saying these cars have solid lifters or hydraulic lifters? Just want to make sure I PM you the right response SRK.

I may have been directive to the OP, but I was not rude. If one of our moderators deems me inappropriate, I'll heed his or her admonition.

It's my understanding that some people in Canada, and several other countries, may also have bad vision. The usual tactic is to change the font setting, as all caps is considered "shouting".

There is no need to PM me - these engines have shim adjusted lifters, and are mechanical rather than hydraulic.

[landar]

SRK, FWIW I thought your response was firm but appropriate. I loved the "change mechanics, not the pump"! Good advise.

Unfortunately, low oil pressure is usually a sign of sloppy main bearings. But that's on a "regular" car. Not a Lex.....hopefully.

But thats getting ahead of the issue. md, when idling, an engine's oil pressure can go as low as ~10 psi and at 2k-3k rpm be around 40-60 psi.

These are just ballpark figures.

Why did you even suspect an issue in the first place?

[eatingupblacktop]

Minor valvetrain noise is normal. Might need an adjustment. Your low pressure warning would light up if it was low. Make sure the warning bulb isn't burned out. Low pressure is common when a high mileage engine starts getting loose. At 170k, that shouldn't be your prob. If you need to, get a second opinion.

[md91ls]

SRK, FWIW I thought your response was firm but appropriate. I loved the "change mechanics, not the pump"! Good advise.

Unfortunately, low oil pressure is usually a sign of sloppy main bearings. But that's on a "regular" car. Not a Lex.....hopefully.

But thats getting ahead of the issue. md, when idling, an engine's oil pressure can go as low as ~10 psi and at 2k-3k rpm be around 40-60 psi.

These are just ballpark figures.

Why did you even suspect an issue in the first place?

I would get oil light sometimes on cold days,not very often. only when starting for firt time in a.m. . would stay on for one to four min. never in warm weather. does have some valve chatter on accelaration, ususaly @ about 1200 rpm,s. the noise @ idle sounds diferrent, sort of an intermitent rough or hollow sound. I dont want to roach engine.

any more advice?. thanks guys, you are a big help. thanks again.

md91ls

[SRK]

It's interesting that the problem shows up more on cold days than warm. What viscosity oil are you using? The first choice is 5W-30, and 10W-30 is fine as well. Certainly nothing heavier than those should be used. And I always advise using the factory oil filter - I found that if I buy the box of 10 filters, they are less than half price of the singles (about $4.30 in Canada, which is less than aftermarket).

A master gauge may still be the best way of positively identifying the problem. As Landar says, the chances of sloppy main bearings is very remote on a Lexus. The master gauge may prove that the sending unit is faulty - and that would be a whole lot simpler.