Hi, I have a 1988 Chevy S10 with the 2.8L and one of the lifter went bad and possible a pushrod as well. . . how do i fix it ?

hi there is your vehicle diesel or petrol

the lifters are at the other end of the pushrods and are operated off the camshaft lobes.

This may not be so easy, you will need to remove the valve cover and check to see if its abad rocker arm or worn pushrod or if its a lifter , you will need to check each cylinder, spin engine to make one valve open and check for play in the other, this way if the intake valve is open that means the exhaust valve it closed and theres no pressure on the pushrod or lifter and if that is loose you will need to look at the rocker and push rod to see whats bad, you will do this to each cylinder to check all lifters and rockers, good day.

If the engine oil was full of antifreeze when the intake gasket went bad, then there is a good chance that there may be some cam and/or lifter damage. A more likely cause of your problem would be that the push rods got mixed up when you put it back together. The intake and exhaust rods are different lengths. If this is the case, and you have turned the engine over, there is a good chance that you now also have a bent pushrod and intake valve. The exhaust pushrod is the longer one and if you mix them up, the piston will contact the intake valve because it will not be able to close due to the longer pushrod. This will bend or break the pushrod and bend the valve stem.

Inspect/Test/Service/Replace Hydraulic lifters can fail for several reasons:

• Dirt lodged in the check valve can allow the lifter to leak. Too much wear between the lifter and the body can cause excessive leak-down. This results in a noisy lifter.
• A lifter might be noisy because of an oil pressure problem.

NOTE An oil pressure problem will be evident on hollow pushrod engines if no oil is reaching the rocker arms.

• A lifter can become stuck because of varnish that accumulates between its plunger and body due to a lack of periodic oil changes.
• A stuck lifter can sometimes be freed up by the addition of an additive to the oil, or by spraying fuel system spray cleaner down a hollow pushrod oil channel.
• Lifters that stick because of varnish buildup can sometimes be loosened up by squirting carburetor spray cleaner down the hollow pushrod lubricating channel, where it contacts the rocker arm.

Hydraulic lifters are not rebuilt because they are relatively inexpensive. It is possible to disassemble and clean lifters but they must be reassembled with their mated parts. Because of the labor time involved, this procedure is usually impractical.
Sometimes a piece of foreign material becomes lodged in the lifter check valve. If the lifter is removed and disassembled before serious wear between the lifter and cam lobe results, it may be cleaned.
Worn mechanical (solid) lifters can be reground.

• The base of the lifter is ground to a radius on a special lifter grinder.
• Roller lifters have a longer service life than standard lifters.
• Wear can occur on the roller pin. Some of these pins are serviceable.

It might occasionally be necessary to disassemble a hydraulic lifter to clean it or to inspect it.

• If this is necessary, disassemble one lifter at a time and pay attention to the order of the check valve assembly.
• Lifter disassembly is done by pressing down on the pushrod seat with your thumb and using a screwdriver to remove the snap ring.
• Remove the plunger from the body; this may require tapping the body.
• Next, remove the check valve assembly.
• After thoroughly cleaning the lifter components in solvent, visually inspect them for signs of wear.
• If the internal components pass inspection, the lifter can be reassembled.
• During reassembly, cleanliness of the parts is of utmost importance.

If your 300 is equipped with a 3.5L engine, high miles, sretched oil changes, the only fix is replacing the rocker shaft assemblys,
they come complete with updated lash adjusters, remove the intake,coils, covers, and rockers, should take you about a couple of hours. there is no cheap fix, sorry. GOOD LUCK. RDJRP

It is possible that some water got into the lifters and after it runs for a while, it will quiet down. However it disturbs me that he noticed them being "kinda loose" and did not investigate further while the head was off.
At that time, all he needed to do was reach over and pull the lifter out of it's bore and look to see if the cam end was worn. (if so, it needs a new cam and lifters) Same applies to rocker pivots. if loose, why?
That is no different than doing brakes, seeing a bad hub bearing and ignoring it.
At this point, since it is all together and running, I'd add a quart of marvel oil and hope it clears it up...otherwise the engine will need to come apart again.
They did change the oil after the job was completed?

Most of the vortecs that i have worked on have hydraulic roller lifters, but i cant say for certain that your engine does, however i am sure that it has hydraulic lifters and they can be checked by trying to push them down in the center where the pushrods contact, if they compress easily the lifter is bad, If they are roller lifters, check for any wear on the roller and how well they turn, it is ok to have some side to side movement on the pin but any up/down movement on the roller is bad. If the are non-roller lifters check for wear, if the lifter looks "dished" or "concaved" rather than having flat surface replace the lifter.

The 3.1/3.4 engines are built the same way. The oil goes through the cam bearings then to the lifters, then the push rods to the rocker arms. The last engine I seen that had a weird problem had the cam bearings spun. Unfortunately there is no easy way to check for this problem short of disassembling the engine.

The other possibility would be bad lifters but loosing half of the engine lifters wouldn't be possible. Sometimes the pushrods wear on the contact areas also but not usually half an engine.

This isn't going to be easy, Good luck.

you can replace both and stop the lifter noise for the rest of the life of the car