1998 Nissan 200sx new clutch slips when hot

With out any other info. like ... did some one replace clutch and pressure plate??, if so ,did they put the correct side of disc plate to flywheel (there is a diff.), did they machine the flywheel surface???, did they replace pilot bush/bearing, throw bearing??? did the clutch get adjusted right (if adjustable) how many mill's before it burns up etc...etc...last i have to offer for >>>excessive clutch disc burning>>> i suggest you keep foot "off" clutch peddle until your going to shift learn how to drive a stick shift correctly , the little cars we have today only have a very small clutch disc in them and they don't tolerate much abuse before they burn up from "slipping" , good luck !!! <:0}

I suspect that the full engagement of the clutch pressure plate is not being achieved
if a pressure plate is held at reduced application pressure , it will continuously slip marginally and this build up to a point where the clutch plate will not absorb any more heat and so it fades and slips completely ( same affect as brake fade from worn pads and too heavy brake application -like long down hill runs )
the area I would check is the clutch master cylinder as it appears that the compensating port is blocked , and holding pressure in the clutch line which with increasing heat from the clutch builds up more pressure and compounds the pressure plate problem
this is identical to a heavy truck clutch problem where full testing produced no problems , yet at 100 miles and on a range the clutch failed completely but when cooled down again tested as good
on replacing the clutch pressure plate and clutch plate it was revealed by a clutch specialist shop that the pressure springs were actually weaker that specifications and were in fact allowing the clutch top slip and so go into the fade situation

I would suggest you get a cheap shop manual to guide you. The basic procedure is put it up on stands, discon battery, remove transmission (or if 4WD sometimes easier to pull engine) remove old clutch parts, resurface flywheel if needed, install new parts using clutch line up shaft, draw down pressure plate bolts in criss-cross pattern and tighten to specified torque (see, you do need a shop manual) and reassemble all. NOTE: clean flywheel and pressure plate suface with Brake-Clean or similar. Replace pilot bushing and throw out bearing too.

The transmission has to be removed. If it's a frobnt wheel drive car, the front axles have to be removed in order to remove the transmission.

The flywheel should be removed, too, and machined flat by an automotive machine shop. With the flywheel removed you may wish to replace the engine's rear main seal since it may leak oil.

The clutch often comes in a "key", which includes a new clutch pressure plate, clutch disk, and a "throw-out bearing" (used by the clutch fork to disengage the clutch). The kit may alos include a broze "pilot bearing", which is used to center the transmission's input shaft inot the engine crack shaft. The kit will include a placstic alignment tool to help the clutch disk while the new pressure plate is attached to the flywheel.

The clutch relies on the pressure between the pressure plate and flywheel. If the pressure is too low, due to weak springs, or worn surfaces, the new disks will be prone to fail. Oil from a bad rear main seal will wipe out clutch components, as well as an improperly adjusted clutch, or bad driving (not you though)
On the hind side, overloading the clutch will wear it also. Shifting too early, bad brakes or bearings. Towing, or the wrong replacement parts. Do this, in high gear, on the highway, step on the throttle. Does the clutch slip? Too weak of pressure. Vibrations or chattering? wrong parts, Oil, or overheating from load. Burning smell? Something is loaded on the driveline or you need to get advice on clutch use. Just sayin for a newbee. Did you turn the surfaces when you changed the clutch? New pressure plate? Clutch disk? Proper Adjustment so it is not engaging? Parking brake not stuck? bearings or brakes hanging?

flywheel bolted to engine, clutch disk and pressure plate, also has a throw out bearing that should be replaced at the same time.
you don't need to replace the flywheel unless it is cracked though you should have it turned down at a machine shop.

clutch is slipping

The first thing to do is to have the flywheel re-surfaced because a warped flywheel will cause the clutch to chatter or shudder when you let up the clutch pedal, and also be certain that the pilot bearing is replaced, it can be difficult to remove the pilot bearing from the end of the crankshaft and you will most likely need to obtain a good pilot bearing puller to remove it.

Clean the bell-housing and the rear of the engine block while the flywheel is being re-surfaced, and be sure that all of the old clutch material and dust has been cleaned from the bell-housing and the rear of the engine block, and contamination from an old clutch disk will lead to early clutch failure.

After the flywheel has been installed and torqued down, then you will need to mount the clutch disk and the pressure-plate assembly together onto the flywheel, and be sure that the clutch disk is facing the right way (usually the spring hub will go towards the pressure-plate assembly), and then start to install the pressure-plate assembly bolts but only hand tighten them for now. After the bolts have been started then use the clutch disk alignment tool that should have come with the clutch kit to align the clutch disk with the pilot bearing, and when you have it aligned so that the alignment tool easily slips through the clutch disk and into the pilot bearing, then tighten down the bolts to the pressure-plate assembly one turn at a time in a criss-cross pattern until the pressure-plate assembly is flush with the flywheel and then you can torque down the pressure-plate assembly bolts. This is a critical step and the better aligned that you get the disk and pilot bearing, and the easier it is to remove and replace the alignment tool, the easier it will be to install the transmission, and the transmission input shaft should slip smoothly through the clutch disk and into the pilot bearing and not have any difficulties mounting up to the engine, and if the transmission hangs up when you are installing it and and the transmission input shaft does not go straight in through the clutch disk and into the pilot bearing, it can damage the clutch hub and the clutch will chatter or shudder when you let the clutch pedal up, and it will shorten the life of the clutch.

After the clutch has been aligned then install the throw-out/release bearing onto the transmission input shaft collar and the throw-out/release bearing fork, and use a lithium based grease on the pivot points of the throw-out/release bearing fork and where the fork contacts the throw-out/release bearing, and if it did not come greased, then lightly grease the inside of the throw-out/release bearing with a lithium based grease and do not over do it on the grease, you want just enough grease to keep the throw-out bearing and the input shaft collar lubricated but still have a smooth operation to it, and you do not want to damage the clutch from oil or grease contamination as this will cause the new clutch disk to slip.

The transmission can now be installed into the vehicle and be careful not to hang the transmission input shaft on the clutch disk or the clutch disk will be damaged. I hope that this information will help you to replace that clutch with a proper quality repair that you will get the most out of.

Lets start with what was replaced : Clutch pressure plate, throwout bearing,pilot bearing,input shaft bearing, was flywheel cut or replaced,Clutch cable or slave cylinder (whatever is applicable,) Lets see what repair shop says. Depending on what they say they did or didn't do we will take it from there.
keep me posted

Check the adjustment of the clutch push rod. It is the rod that connects the clutch pedal to the clutch master cylinder.