just a few questions/concerns about my engine condition...

[MOB240]

below is a list of some things i've noticed about my engine. any help would be nice. first of all the car is 1995 and it has approx 174,000 mi. on the odo.

1. white smoke out exhaust2. i have to keep refilling the coolant overflow tank or the temp gauge acts like the car overheats when the engine really isnt hot at all. i fill it up like once every 2 months. but whats up w that? and my heater blows cool air. even when the car is warm3. the car burns oil fast, like i have to refill it every 2 months or so.4.check engine light has a mind of its own, sometimes its on, sometimes it isnt.5.sounds like there's a rattling towards the front of the valve cover, which im guessing would be my timing chain.

[rogoman]

1 - water vapor, possible blown head gasket2 - possible air pockets in coolant system3 - probable worn rings or external oil leak4 - ECU fault code being set, then being cleared; also possible wiring problem5 - timing chain guide broken or very low oil pressure

[MOB240]

how do i check/ fix all of these problems?

[rogoman]

1 - water vapor, possible blown head gasket2 - possible air pockets in coolant system3 - probable worn rings or external oil leak4 - ECU fault code being set, then being cleared; also possible wiring problem5 - timing chain guide broken or very low oil pressure

1 - Run a compression test on every cylinder. Fill the radiator with coolant all the way up into the filler neck; when running the motor, look for constant bubbles appearing; this indicates combustion blowing into the coolant.

2 - Your best bet may be to drain down the coolant and start all over again with the filling of the coolant. Here's how I do it: - drain coolant - open the bleeder screw - optionally jacking up front of car helps to purge air pockets - fill system until coolant starts coming out the bleeder hole - close bleeder screw (not too tight; screw is easy to break off) - continue filling until coolant is at the bottom of the filler neck - do not put cap on the radiator - start motor; as coolant starts to warm up, you may see a few air bubbles - squeeze the hoses by hand to free up possible air pockets - put cap on radiator

3 - A good way to test for oil burning is to first fully warm up the motor.Stand behind the car. Have someone rev the motor to 4,000 RPM and hold at that RPM for about 15 seconds. If you see a lot of blue smoke come out of the tailpipe, the motor is burning excessive oil; Time for new rings.

4 - To do an ECU code readout, go to http://www.240sx.org and look up 'ECM, reading trouble codes DOHC' in the FAQ section.

5 - Remove valve cover and look down along the two chains for excessive wear of the guides. Also if there's a top guide, remove it; it's not needed.

To check for low oil pressure, 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