Richard A. Thomas

My 1991 L98 needs a new water pump. It is already running a little hotter than it used to ever since the head gaskets were replaced, so I want to get a good quality pump. I'm looking at the Edelbrock Victor series model 8815. The JEG'S site says this pump is "reverse rotation". Does this mean it's intended for "reverse flow cooling" engines? I know that didn't come out until the LT1 in 1992. Is this the pump I need for my L98?
Secondly, I've only replaced one water pump before (in a 4.3L Vortec V6, which is a 350 V8 with 2 cylinders removed). Neither I nor a couple mechanics ever were able to get all the air out of the system. The temp. guage showed the engine ran a little hotter than it used to, and occasionally I would squeeze the upper radiator hose and felt no pressure. Any advice on how to get all the air evacuated from the system? Thanks.

zr1fred

I believe the "reverse rotation" refers to which way the pump turns. Serpentine belts sometimes turn a different direction than the older multi belt system. If your system is not building pressure, you have a leak somewhere, probably a bad radiator cap.

Square

I just replaced the water pump on my 86'. I used a "FlowCooler" water pump from Summit Racing. I believe it was $104.

I had to remove the A/C bracket and disconnect the fuel send and return lines to get to the water pump. The pump itself was very simple. I also replaced the lower heater hose (which I got from NAPA auto parts). I had to cut the hose to fit, but it had the correct bends.

The procedure I use for "burping" the L98 is:

- Fill the radiator
- drive the car up on ramps, so the front is elevated
- open the radiator cap and start the engine
- Once the thermostat opens, the coolant level wil drop
- Have a second person hold the engine at 2,000RPM, this will "pack the radiator" and hold the coolant down in the radiator
- top off the radiator with coolant, and then reinstall the radiator cap

I found this procedure here on the forum and it has worked for me.

RandyJ75

No need to burp a '91, the cooling system is different.

I did mine a couple of years ago, and changed all of the hoses and thermostat. You will need to remove the A/C bracket to get it out, not too bad a job, depends on how young you are.
I used and Edelbrock high flow pump, which works great, but caused my intake manifold to start leaking coolant.
Just take your time, it's not to bad a job. Check back in w/ any questions.

Randy

M.J.L.

Just replaced mine as well.

Demonic85

The water pump is a reverse rotation pump. The reverse cooling on LT1's refers to the coolant being pumped to the heads first rather than the radiator.

zzpw3x

I did mine a few weeks ago. It took me a solid 6 hours. Part of the time was wasted when the service manual told me to remove the air pump and air pump bracket. I kept looking at it and didn't understand why it need to be removed. It turns out that it doesn't.

You may want to get new o-rings ahead of time for the fuel lines. Advanced auto had them on hand.

tshirttom

So is this the same for a L98 with a reserve pump installed? I recently installed an Edelbrock reverse water pump and used basically a standard serpentine belt.

vader86

I use a Stewart Stage 1 pump, but would use a FlowKooler as well.

Red Tornado

Flowkooler here

crunchy

I replaced the water pump for my '90 with the 69 dollar special from Schucks about a year ago. The cheap one turns out to be cast iron instead of aluminum. It just started to leak coolant from 'some where up front'. After removing it, it looked like it was leaking from around the gasket. I cleaned up all the gasket material and tried dry fitting it back in place. It rocked back and forth without seating nicely against the block. I checked the pump on the granite kitchen counter top and it was perfectly flat. I did notice where it touched the timing chain cover that there was some corrosion. The cast iron pump body seems to be thicker than the aluminum one was. A hammer and a severe tightening solved my leak.
And yes, the belt tensioner, the fuel lines(get new O rings) and the air conditioner all have to come out to get to the water pump.

DM VETT

Do you have to burp a 1990 L-98?

rpoL98

I also had to remove my idler pulley. not enough forward clearance to get the AC bracket off of the waterpump long stud.

samsonb

That is a good price on a water pump. The prices I was seeing from the Corvette venders were over $300.

86PACER

How do you know it's the pump? I'd remove the upper shroud and take a look between the radiator and the condenser first if you have not already. It's common for this area to fill with road debris and leaves, restricting airflow and reducing cooling efficiency. Stat opening up, fans run? Assuming you did a flush and stat change when the head gaskets where changed.

frenchyoliver

no need. just fill it up at idle.
Fill up the radiator by the upper hose first.
You re done.

gmboileau

Unless the water pump is leaking it's unlikely the cause of overheating.

justmax36

aftermarket water pumps have a tendency to bind a little bit on the timing cover. But thicker gaskets, which they do make is an easy $3 fix to the problem. Or you can double up Regular Size gaskets just depends on how thick you need it. But the thicker gasket they make for this issue seems to be exactly the right size without throwing off pulley alignment. And eliminates all the banging and excess gasket sealer LOL

justmax36

I'm finishing up on the rebuild on my 89 l98 and I've got the flow cooler 1688 and it says that it's both standard and or reverse rotation. That's a little confusing to me. I understand that on the Belt setup if it's on the grooves it standard and if it's on the smooth side it's reverse. But isn't it still turning in the same direction in either case? So how does that make it standard or reverse? To me that means it will work with either setup but that doesn't make the water pump itself both so that's where I'm confused. But flowkooler says under the specs and I quote standard or reverse rotation water pump. Okay that's my headache of the day with this dang motor LOL well that was after I figured out the water pump scraping against the timing cover issue!

kostas86

Had mine replaced in spring with another OEM one.