Im thinking of buying a 96 z28 from someone... Anyways, they had put a new waterpump on, along with the opti, plugs and wires.... The car overheats now if ran for too long. He said the fans come on as expected and had no problems before the work.

Im guessing that he has air in the cooling system.. what do you think?
He also says if he has the temp. setting is on hot, its only lukewarm(never gets hots) thru the air vents....?

Its a beautiful car and Im probably goin get it even if he doesnt fix it...
All opinons valued!
thanks

 

Sounds like air in the system, or the thermostat isn't opening. With the engine running at operating temp, touch the upper radiator hose and see if it's hot. If its not, replace the stat.

 

now that you say that, he said after a test drive, only one side of the radiator was pretty hot, as for the other was cool...

keep em coming

 

This should tell you how to get the air out of the system (courtesy of shoebox): http://shbox.com/1/4th_gen_tech2.html#radflush

 

It's overheated already which it sounds like it has...move on. Head gasket issues are coming your way down the line. I guarantee you he is selling the car because of the overheating issue and it probably already has a minor head gasket leak. People do this all the time.

 

Sounds like leaking-clogged heater core, based on your description of no heat in cabin. I had a leaking heater core that kept air in the system it seemed. (the system wouldnt stay pressurized very well) I wound up bypassing that bitch, since I dont need a heater here.

I would re bleed the system.

 

Well my thoughts were air in system... Also, I guess a new waterpump could have a faulty termostat...?

As for the Heater Core... Do I just flush that? Where do I go from there.

 

Its a very good possibility there is just air in the system. However, if the car has been run for too long in the red, there is a good chance of damage occuring. Its something to maybe look into before buying the car. Clogged heater cores are pretty common on these cars, usually they can be flushed by pulling the rubber lines and running a garden hose through one.

 

also make sure he put the water pump drive back on i have seen some poeple not put it on causeing it to heat up due to lack of circulation....

 

the pump drive is a good idea but a thermost can be instaled wrong or just be bad, thermostat is the only reason your radiator wouldnt be hot

 

Most people dont remove the drive when you replace the pump...I didn't.

 

Another vote for air being in the system and the heat not working becuase the water isnt flowing to it.

Unless you are getting an out of the world deal on it i would look else where.

 

Thanks for all your input! I plan on getting the car this Saturday! Ill let you know what I come up with!

 

(copied over from LS1Tech)

I had the same problem with my 95 Z. The drive coupler (or sleeve) on mine was
stripped (the inner grooves), so the pump was getting turned probably 80%.

There is a drive gear that comes out through the timing cover and this drive gear
points (faces) towards the radiator. On the backside of the water pump, there is
a driven gear that points towards the drive gear - when the water pump is bolted
up, the two gears face each other, almost touching. To "connect" the two gears,
there is a coupler that is splined on the inside and it is this coupler that slides
over each gear, "connecting" them. If the inner splines on the coupler are
stripped, the drive gear will spin (it's driven off the cam timing gear), but it
won't spin the driven gear on the water pump, or will be "partially" turned.

The quickest way to determine if the coupler is bad is to take the front inspection
cover off the water pump and attempt to turn the impeller by hand. If the impeller
turns, then it's the coupler, or worse, the drive gear. I'll see if I can find the
photos I took of mine, so it all makes sense.

Look here for two scanned in images from a repair manual, showing the drive
and driven gear and the coupler: http://picasaweb.google.com/calder.cay/Z28

I've posted a couple more photos of the water pump driven gear, drive gear, and
the coupler: http://picasaweb.google.com/calder.cay/Z28

 

I'm telling you, dont get all excited and over look problems its happened to me many times with buying used cars. Look into that head gasket problem or you'll be sorry later on down the line when you have to throw down 2500 to have it fixed, or do it yourself and spend a few hundred a week doing it.

If I was this guy, I would have exhausted all my options to try and get that anti-freeze problem fixed before I sold the car because it would raise the value so much, I wanna say this guy probably has taken it to a shop or two and they either couldn't figure it out or was something serious which is why he is selling it.

Hope you know what you are getting into.