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Greetings Oldshewel, Could be a myriad of things from a faulty oil filter, sending unit, electrical...but the main thing is...DON'T DRIVE IT IF THE OIL LIGHT IS ON! You'll be sorry! Thanks for that..... I'll know what's going on with it in the AM, I am going to put a mechanical oil pressure gauge on it to determine if that's the problem.

I got my 91 LS400 put back together but the oil light is flickering on and off. Let me attempt to describe the situation. I start the car, and it idles just fine, no oil light (oil light will not come on if I do not rev the engine, it idled for about 25 minutes yesterday while i was filling it up with coolant), if I then rev it up a little, when the RPMs come back down the light flickers on....I then rev it up and the light goes off, but when the RPM's settle again it flickers on and stays on. It's like the oil light will not come on until I rev it up, and then it stays on at a higher RPM (higher than idle) but turns off when I rev it....This pattern repeats itself until the oil light stays on for any RPM under about 2500. I can put it in neutral and turn the car off, then back on, and the light goes back off for the first few minutes and the pattern starts over. It's like i am re-setting the electrical system.....This leads me to believe it is an electrical problem, because i will only kill the engine for about 1 second. The Cam seal was blown out, and spewing oil prior to replacement, so I know I have oil pressure (i replaced the seals), also the engine is very quiet and smooth. I guess my question is, has anyone ever had a similar problem, and is there a way to check the Oil pressure sending unit? It is the Red oil light in the middle of the Tach/Speedo, not the orange one below...not sure if that makes any difference, but I noticed 2 oil lights. Any suggestions are much appreciated. Grayson

She runs! It turns out that i am retarded when it comes to old OHV motors. Now all I have to do is replace the cam seal, button it all back up and she's ready to sell. Thanks again for all your input and advice, it's great for us n00bs! Anyone wanna buy a 91 LS with 176k? It's in Mass, but spent all its life in Texas. Pm if interested Grayson

So...i found this http://www.lextreme.com/timing2.html wish i'd seen it sooner. Found out that I lined up the Cam trigger mark instead of the timing marks. I'll change tonight and report back. Wish me luck!

I had a very similar problem with my 1991, every time i hit the brakes, dash lights would come on, radio would cut out, and sometimes the car would just die. It ended up being a bad connection on the battery itself. The main terminal was ok, but there was a ton of build up in the wire itself (the battery terminal had been replaced with a clamp/crimp style end). I cut back the insulation, cleaned the crap out of the wire itself, and put a new battery terminal on. Completely fixed the problem. I would start there, check both positive and negative cables, if you've got a multi meter, you should check ohms resistance between battery terminal and the ground on the engine, as well as the positive to the distribution block. Hope this helps. Good Luck Grayson

Thanks for the advice guys, I will check these things as soon as I have time...school and work have been kicking my !Removed!. I'll keep y'all posted.

Ok, I have another question. After quite a few hours replacing the front main and timing belt, the car won't start. I followed the instructions at http://www.lexls.com/tutorials/engine/timingbelt.html but apparently I didn't do something right. I lined up both cam marks and the crank marks, rotated the engine twice and the all lined back up. I did this several times to make doubly sure, but the car still won't start. The sound when cranking is a little different, and it seems like gas vapor is coming out the air filter hose, could I have been off some how? All of my experience is with domestic V8's (much simpler) I have a feeling I am going to have to re do the timing belt...Could I be missing some sensor, or plug, or something stupid like that that could be messing things up. I have confirmed that i have both fuel at the injectors, and spark at the plugs. Any suggestions would be much appreciated.

Thanks for the heads up. Although I am looking to sell my LS ASAP. I picked up a 2007 Subaru WRX STI Limited as a daily driver...not a bad upgrade from a 1991 LS! I really don't want to put any more money or time into the Lexus, and wanted to sell it with the blown seal for like 1500-2000 bucks, but so far, no luck...people get scared when the engine pours oil. The car is in great shape with 176k mi. The pain is a little faded on the center of the hood, roof and deck lid, but has never been in any major accidents, and to the best of my knowledge the only thing wrong with it is that the front main is blown out. If I fix the front main and really buff the paint, what would you guys suggest I ask for it? It's a Texas car, so it has absolutely no rust, and I live in Massachusetts now (yes, it made the 2000 mile drive up here just fine!) Any thoughts/input would be appreciated. Grayson

Where would I acquire a crank shaft saver? Is it something I can get from the dealer, or have to dig around online to find?

Awesome! Thanks so much. Is there a place i can download the shop manual on here? It always helps to have the instructions.

The front main seal in my 1991 LS 400 is completely blown out, pouring oil out the timing cover. I am just trying to get the car to where it doesn't leak and sell it. I am wondering how difficult it is to replace this seal, and what type of seal it is. I know how to remove all the covers and timing belt, but am unsure how the seal comes out because i've never torn that far into my lexus before....my experience is mainly on older domestic cars with the dreaded Rope seals. Is it a tap in seal? Any advice or a link to a Shop Manual would be much appreciated!

Well, i tore it apart and even the guide pin that holds the cam gear to the cam was broken. I had to drill it out, replace, put a new gear and bolt on, then replaced the cap and rotor...after all that the front main seal is gone and it's pouring oil out of the timing cover...at this point im thinking i just sell it for 1500 to 2000 bucks and cut my losses. It looks like the front main seal is bad, but not 100% sure. It's one of those situations in which I could tear into it, replace the seal, but what else could be wrong. Has anyone ever heard of anything like this happening before?? I'm baffled as to why this all happened at the same time...the car drove from Texas to Massachusetts no problem, and then was parked for 3 months, upon first crank...bam, down goes the lexus.

Got a cam gear?

I need to know what the torque spec is for the Cam Sprocket/Gear bolt. It's a 19mm headed big bolt with a giant washer built onto it. Can't find a manual. it's on an 1991 LS 400 motor

I ordered a new bolt for the cam, it'll be here some time in the next few days....So I decided to find a grade 8 bolt of similar size to see if that would work. It holds just fine, the car starts now, but it is still running very rough. Any suggestions? Is it possible for the belt to jump time? if so, is there an easy way to check for that? I have a feeling that it is out of time. The car was to be sold this Sunday, and I really want it up and running so I can get rid of it. Any and all suggestions are very appreciated!