need a few answers

[saraleigh]

I am the proud owner of a 1990 Plymouth Laser RS (manual, turbo, fwd). I bought this vehicle about 4 months ago and felt it to be in pristine physical and cosmetic condition, and very well maintained, seemingly 5 years old rather than 16. Unfortunately, it is not 5 years old, and has several annoying and/or mysterious problems to prove it. I only use Mobil 1 Synthetic 10w-30 and have a decent knowledge of DSM, but have only done invasive work on a 2g Eclipse GST.

I will start with what I am confident diagnosing: gas mileage is embarrassing-- approximately 14 mpg city and 19 mpg hwy. I suspect a dead O2 sensor is to blame, as well as a few items within emissions system -- specifically the disconnected thermo valve.
Also, a progressively louder and more frequent metallic clunking is emitted from the rear passenger-side wheel well while driving and ceases when I brake. Braking function is not affected, but since driving on some unpacked dirt roads this past week, a funny rubbing noise has joined the clunking. I suspect loose brake pad hardware.

And as for the "serious" (and by serious I mean, "will probably cost a lot") issue: oil pressure is extremely low (almost sitting on L) and temperature also seems low (never reaches center and must run 25+ miles to rise from C). The oil light has never lit up, but level of oil is low (according to the dipstick). I first noticed this problem 2 months ago, a few weeks after the first oil change since I have owned the car – I had it done at Pep Boys. The dipstick did not register any oil, so I added a quart of oil and pressure returned to normal. I live in Los Angeles and must park on the street, so I was unable to accurately check for external leaks. Yet, this past week I traveled inland to a resort in the mountains, and so was very capable of detection. Unfortunately (I think) there were no clues left for me on the cement, even after driving the car 70+ miles each day and then parking in the same spot 12+ hours every night. Oh, and I added another quart of oil before leaving for the trip and one after arriving due to the seemingly low oil level and pressure. Granted, in the past 10 days I have put on mileage that would have usually taken me at least 2 months, but the pressure is again alarmingly low. Yet, I cannot bring myself to add any more oil, as it doesn't seem to be leaving the car, and I can only assume that the engine is working with 7 quarts of oil in it right now. I am figuring this to be some internal oil leak (bad head gasket?), or maybe a bad oil pump... yet due to a recent promotion at work, I haven't the time/daylight to perform exploratory surgery on the engine.

So... I would really appreciate any input you may have concerning any or all of these problems. In addition, any estimate of time left before repair is absolutely necessary would be great as well. Thank you so much.

 

[Eclipse45150]

Well, I dont want to run you in the wrong direction, so I am not going to anwser about the serious question. With that said, if your o2 sensor is bad, is it sending any codes because most of the time it will, your gas milage problem could be combined with the prob w/ the oil ect... as for the clunking and rubbing if its the brakes it sould go away after you come to a stop, atleast for a little while, since you said it clunks and rubs when in motion I would put money that you probably have a bad hub bearing, happened to me a few months back but I thought it was a strut at first, I would go somewhere that gives a free estimate and get it checked out first though cause since they can see the car and hear it they can tell you better than me, but if it is the bearing you really dont wanna drive on it except to get it to the shop.

 

[xveganxcowboyx]

I don't suppose it woul dhurt to have the oil changed again. That way you can be sure of the level. Preferably do it yourself so you can check the oil out.

Also, check the inner shield dealy (name is escaping me right now) on the wheel. Half of the wheel noises I've ever had have been from those being bent or rusting loose.

other than that, I won't speculate, because I really don't know.

 

[DevilSperm]

1g's are notorious for low oil pressure reading. The pumps just plain suck. So it may not be as bad as you think. My light flickers at least once a day, but my engine is probably a little more tired. Also, a bad o2 wont trigger a cel on a 1g. Find someone with a logger near by and hook it up. That is the best way to tell, though that gas mileage doesnt seem all that horrible to me. Check to make sure the parking brake mechanism isnt stuck, it will keep pressure on that pad all the time

 

[saraleigh]

so, a few things have changed... after my recent long distance driving stint (due to vacationing in the mountains), i have discovered the oil leak to be external. it must only be leaking at high speeds though, as there is never any oil puddles underneath the car. yet, the oil pan and crank shaft pully are coated, and there is a good amount of oil under the upper timing belt cover (head gasket?). so, i suppose that all this oil is spraying out once under high oil pressure conditions. anyone know a good dsm mechanic in los angeles?