My oil light has always been on since I bought my 91' 740 (b230f)... people here n there have told me it could be low oil pressure, could be the o rings that are worn... so anyways...I had another 740 (89') that I bought for parts...motor was fine... anyhow...I had to replace the crossmember cuz it cracked... while I was at it I'd figure I should check out the oil pump and maybe replace it with the 89' one...well I just did.. I put sum teflon tape on the tube where the o-rings go... the old pump had a bunch of old silicone trapped in the mesh...well anyways...dont know if its me being paranoid but I cranked it and let it run for a while...and it felt like it was runnning hot...I checked the temp gauge and its normal, opened the oil cap to see if theres circulation and there is...dont know if I did sumthing wrong...I dont think so... it was easy as pie...can I get sum input...? oh.. and for sum reason it just shut off 10 minutes after I started it... cranked it acouple of times and it started again....it seems like its running smoother than before...I dont know... I love the hell out of this car... I rebuilt this thing myself n this was the last of what it need...I would hate to have damaged the engine...PS.. oil light is still on after installing the other pump...??????

 

if there was a bunch of silicone rubber bits in the oil pump pickup screen, then there's also probably a bunch of silicone gunk in the oil passages all over the engine. meh.

maybe a good idea to swap the whole motor for the one from the other 740. keep your ECU and harness and stuff. 89 was the first year for LH2.4, by 91 it was pretty solid.

you said you rebuilt this engine? did you use any silicone sealants when you did that? what exactly did you rebuild? top end, bottom end, everything?

also, what weight oil are you using? you should use 10W30 for all sane temperature ranges, I'd only use a heavier oil like 15w40 if you lived in the desert and then only in the summer.

 

Teflon tape is not a replacement for the o-rings on the oil pump tube. I doubt that they would seal for long and you will end up with low oil pressure - certain death to the motor should you drive it like that.

Really, I would pull the pan and check the bottom end of the motor out thoroughly. Check the mains for wear, check the oil pump for wear, check the oil mains for gunk, etc.

Really, as Pierce said, it may be easier to just swap in the 740 engine. But if it were me, I would check the same components on that engine prior to installation since it is easier to do all that with the engine out.

 

When I put the teflon tape I put back the o-rings where the were, I only put the tape just in case the o-rings were worn...I cleaned out the oil pan thoroughly...didnt use excess silicone, just enuff to seal...the oil pump that I took out of the other b230f was clean, I've done alot to this car in the past 2 years... all relays, sensors are new... cleaned out all the connector harness' cuz they had oxidation, jumpered the OD relay cuz it wasnt shiftin into 4th gear, swapped the tranny, new kickdown cable, cleaned out the fire trap and Idle control valve, new water pump...new distributer cap, rotor, spark plugs, wires...new timing belt, took out all the fuel injectors n cleaned them out...plus the cold start injector, what else? new fuel pump n filter, radiator has been flushed out recently...retrieved the codes... the only one I'm gettin back is the code for the knock sensor which I switched out from the other 740... didnt use a torque wrench so I know its not sending the proper signal, found my wrench so I'll get on that today...the only thing I didnt do is the head gasket which is fine...I just put a whole new front end in this last week...rack n pinion, crossmember was done yesterday along with the oil pump...steering arms etc...the new pump is circulating cuz I could see when I open the oil fill cap... so if that working then I'm good right? I let it run for a while this morning to see if it over heated and it didnt, oh I live in the tropics so the thermostat was thrown out the window along time ago...their nuthin but problems in this year round heat....so it tends to run cooler...

 

ah. to most folks, 'rebuilding an engine' is more typicaly used to mean boring or lapping the cylinders, new rings, new bearings, refurbish the head, new valves, and replacing ANYthing inside thats worn (pistons, rods, pins, crank, etc etc).

 

i'm gonna do that with the other block...but for now I'm fixing up what I have in the car already so I have no worries...its not for racing or nuthing like that... more like a... I have a 22 year old car thats simple to work on and it wont leave me on the side of the road..lol..when I lived in the states I had 3 trucks no cars...moved down here n needed sumthing thats safe and reliable my wife gave birth 2 weeks after we moved here...so I bought this 740...well it used to leave us everywhere...at fisrt.. then I started to put money into it and then I got lucky and bought a 89 in great condition, with a bunch of new stuff that I needed for the 91...anyhow... long story short.. this car runs around the whole island like it aint nuthin...I fixed the minor bodywork and even successfully installed the chrome grill headlights n trim...I kept the 91 bumper cuz I didnt like the flat bumper the 89 had...its a looker now so I'm just replacin and cleanin it up so it doesnt look like a bucket..interior is leather in great condition, it has become my project when I have the time and money...I love it cuz its economical and safe for the family...its like a tank..lol..like I said before.. I've put everything new into it.. the only thing that is left is the engine block...but I'll do that after the holidays...got another baby on the way too so things are tight right now... I just need sum info on the oil pump situation... my guess is... if I ran it for 2 years with a clogged oil pump and had no problems with the block...now that I installed the other pump which wasnt clogged I should have no worries right?...its a mechanical pump...and the oil is circulating... what should I look for if it either stops working or if theres clogging in the inlets through out the engine...the hot air I was feeling was the fan blowin the heat from the engine...