loud ticking sounds from motor

[RobTL]

89 bone stock 240sx with 287k. After the car is driven and then parked for a short time. When the car is started up sometimes you will hear a loud clacking/clicking sounds coming from the motor. Yes it has oil. If you rev it up sometimes the sounds will go away and sometimes they wont. If you drive the car while it is making the noise and you are bearly on the gas it will continue to make the noise. But if you put it under load (drive in 5th gear at 35mph) with full throttle it goes away while under that load. But if you get out of the gas you can still hear it. If you hit the freeway and just keep it at a steady RPM it will gradually go away. I know the lifters can go bad in these cars and i have also heard of the cam chain tensioners/chain guids go bad as well. Yes i know its time for a new motor but right now its just a cumuter. Any thoughts? Am i thinking on the right path???

[rogoman]

It sounds like you have low oil pressure which could be caused by several factors. Worn rod/main bearings. Plugged up oil filter. Dirty oil pickup. Most of the time it's the oil pump which may be worn and not producing the proper oil pressure/volume.

You can check the pressure very easily by installing a temporary mechanical oil pressure gauge. You would remove the oil sensor which is located next to the oil filter and install the mechanical oil pressure gauge in it's place; you may need to get an 1/8 BSPT to 1/8 NPT adapter to hook up the gauge. With the engine fully warmed up, the pressure should be as follows:idle - at least 11 psi3000 RPM - 60 to 70 psi

If the oil pump needs to be replaced, it's easy to do so on an '89 as it bolts on externally.