Cajun CB

On a 1986 L98 coupe:

Chilton's and the factory manual calls for the AC compressor being removed to change the water pump. Hayne's indicates it can be done with out removing the AC compressor.

Has anyone used the Hayne's method? Any advice?

pcolt94

The Haynes manual can pertained to several years. The FSM is dedicated to one year.

I would see I could get the pump out. Loosen the mounting brackets is need be. But I would not completely remove the compressor and disconnect the Freon lines.
Just my advice an opinion. An 86 guy might know for sure.

gerardvg

Check the a/c bracket does not go over the water pump, the bracket may sit on the water pump and is bolted to the pump/ engine.

My 85 doesn't have the 84-87 a/c anymore, i swapped to the 88-91 type., i know the 88-91 does and you need to remove the bracket to get the water pump off.

You do not need to disconnect the gas hoses, you can remove the compressor from the bracket, then you can move it to one side so you can get the water pump off.

Cliff Harris

The AC compressor bracket is mounted on the water pump bolts. They're not really bolts, but actually a combination of bolt and stud (I don't know the name for that -- this just came up in another thread but I forgot the name). It's like a bolt with a stud sticking out of the head. The bolt part holds the water pump to the block. The stud part is where the AC compressor bracket mounts. You definitely have to take the compressor bracket off of those studs. They're pretty long (about 2"), so the bracket needs to move forward quite a bit.

There's also a brace that goes from the back of the compressor to the exhaust manifold that needs to be removed.

You also have to take the Torx bolt (T-40) out of the bottom of the compressor (it goes through the bracket and compressor and into the head from the front). This tricky little bolt has a flat ground into one side of the head to clear the compressor pulley. My recollection is that the head hits the pulley, so you need to loosen it a little, move the compressor and bracket forward and loosen it some more. After it's free of the head you have to turn the compressor pulley until one of the "gaps" in the rim lines up with the bolt. Then you turn the bolt so that the flat is toward the pulley and it will come out.

The fuel lines come up through the inside of the compressor bracket. You need to unfasten them from the fuel rails. Check the O-rings. Mine were thrashed (they've been off several times).

There is also an A.I.R. pipe that goes through the compressor bracket. It goes to the catalytic converter. I think you can just undo the rubber coupling for that.

There is also some A.I.R. plumbing and stuff bolted to a hole in the top of the water pump. The A.I.R. solenoids and valves are mounted on the compressor bracket. I vaguely recall that some of that stuff must be removed.

I suggest loosening the water pump pulley bolts while the serpentine belt is still on to hold the pulley. Otherwise it's pretty hard to hold the pulley with your hand and break loose the bolts.

Cajun CB

What is the difference between a "performance" water pump and a regular one? Is the performance pump needed or desired?

357L98

The water pump can be removed without totally removing the compressor. There are two bolts through the compressor bracket to the water pump. Remove them and the other compressor bracket bolts, pull the compressor aside as far as you can, and you will have room to remove the water pump. A stock water pump will work fine, no need to spend the extra money on "performance".

c4cruiser

I have a standard type W/P on my '87 and I use the car for both autocross and track days. Never had a overheating issue; the radiator is clean and I have a 180 degree 'stat.

I would think that unless the car is highly modded, the standard pump should work fine. But make sure you use a quality pump. It can be hard to find a brand-new pump and lots of the parts store rebuild pumps can be iffy in terms of how long they last.

As long as you're replacing the pump, it would be a good time to replace the lower radiator hose. It can be areal PITA to change if you aren't doing and R&R on the pump. I would suggest a new upper hose too just so both hoses are new at the same time.

Joe C

to change the water pump on a 1986 L98 coupe -

step 1. ditch the Haynes manual.

step 2. get a red cover, factory service manual for a 1986 corvette



seriously, no need to remove the AC compressor - unbolt it, along with the mounting bracket, and move them out of the way. installation tip - one of the mounting bolts goes into the blocks water jacket - as I recall, lower LH bolt. make sure you seal those threads.

Cajun CB

The red cover factory manual says to remove the freon from the AC system and remove the compressor.

Cajun CB

Everyone-thanks for your ideas. They have been VERY helpful.

Joe C

strange - I've done water pumps on an 85, and my 90. neither FSM says to remove freon or the compressor.