Coolant temps down south

[CLABORN1960]

Thanks for the great feedback..... how much of this can I do myself and how much should be done by a reliable mechanic??

 

[Vettelt193]

depends on how good you are with tools... all of it can be done by the weekend mechanic though, there are really no special tools required (i would suggest a belt removal tool, basically a long bar, to get the belt off though, because the belt tensioner is in a strange place and hard to get torque on with a regular wrench)

If you need more instructions I can help you out.

 

[CLABORN1960]

The radiator flush wont be much of a problem, and I will check for debris..... what is an opti-spark and how much is that part?

The things I learn about my dream car here in this forum..... you all be gentle please.........(smile)

 

[Vettelt193]

the opti spark, in toned down form, is a distributor... In order to replace it, you must take off the waterpump anyway... they are quite expensive... you are looking at a $1000 repair bill if you let a mechanic to the job (opti alone). Do it yourself and the part will cost over $400 from chevy... you can get a rebuilt unit from autozone if you want as well, for much less. The job takes some time, but isn't difficult (with the exception of the crankshaft pulley, which is hard to separate sometimes from the hub) The waterpump is very easy to swap, there is nothing really complex about it if you take your time. I will try to dig up instructions on the opti spark swap and post them for you.

 

[Vettelt193]

http://www.houston-f-body.org/tech/optispark/

this is opti spark instructions for an F-Body... once you get everything out of the way, the instructions should apply for the waterpump down.

this one is here on CAC http://corvetteactioncenter.com/tech/c4/optispark.html

 

[96Holly]

Water pumps....

I recomend if you are going to replace the water pump go with a reputable source, like a GM dealership. I spent $169 bucks for a "new pump" and it went bad after one tank full, 300 miles or so!!!

My 2 cents...

 

[vettepilot]

Quite correct, I always go with genuine GM parts for my Vettes, and other cars get the genuine brand replacement parts. They are initially more costly, but in the long run last longer, don't have to worrry about perfect fit, and any other specifications not being correct. You should be able to get a genuine GM opti-spark and waterpump from GMparts.com for a reasonable price if you are doing it yourself. By the way, don't let anybody talk you into an opti-spark for an F body. They are different from the Corvette opti-spark. Plus, the F body units can be rebuilt, but the Y body cannot.
vettepilot

 

[CLABORN1960]

Someone mentioned in an earlier post that the waterpump may be leaking water into the opti-spark (in my particular case). My question is this, if that is the case, why wouldn't it leak all the time and not just when the coolant temp is high? Why wouldn't the car be stumbling/jerking whenever its on, as opposed to doing it in the late afternoon heat?

Excuse the questions, just trying to understand the beast that I drive...... Oh by the way it has 104,000 miles on it. When I purchased it 75,000 miles were on the odometer.........

 

[Vettelt193]

It really should leak all the time, not when the coolant is really hot... In late afternoon heat 2 things happen... 1) the hot air is less dense, so there is less oxygen in it, so your car can't make as much power. 2) the engine is hotter, which increases the chance of pre-detonation

With those two things happeing, your car needs to retard the timing... when it is cooler and the air is cooler, it is ok... let's just say your opti is stuck at a certain timing... it is ok when it is cold, but it is too far advanced in the adverse conditions.... one of the reasons why the LT1 has so much more HP than the L98 is the variable timing... The L98 has to have its timing set up for the worst conditions it can encounter while the LT1 changes it on the fly, so if the better the conditions are, the more the LT1 outperforms the L98

 

[carguru]

Also you can look at the underside of the hood for signs of a leaking waterpump. There will usually be a slight wet streak that extends from wheelwell to wheelwell on the underside of the hood. This is usually a good indication the pump is starting to go.

 

[vettepilot]

Not on the LT1/LT4 engines, the shaft is driven from the rear, not like the front shaft drives with a pulley that, through centrifugal force, slings the leaking coolant around. Usually what happens is it just dribbles from the bearing weep hole.
vettepilot

 

[96Holly]

Leaking and flinging.....

The indication that I had was gunk on the bottom of my hood going cross car. The line of gunk was in line with the belt. The leaking pump (weeping hole) dropped fluid onto the belt which then was flung off at the A/C pully... that is were most of the gunk was located.

Once I saw that fluid on the hood I got out my mirror to see the weeping hole and there it was.... DANG....ad

Schmootz all around the weeping hole....

96 LT4....

 

[CLABORN1960]

Thanks again for all the useful tips/pointers...... Last night I let the car idle without the A/C on and the second fan DID NOT come on. The day before it did come on when the temp reached 227-228. The temp rose to 235 and still no fan, so I suspect the relay is bad, and I will replace them today.

 

[Vettelt193]

you can test the relay by swapping them... basically you can just unplug both of them and switch the wires... they are mounted on the drivers side of the radiator cover.... The fan motors break, and there is a good chance the relay is ok, but the motor is shot.... also, do both fans run with the A/C on? or only the 1 fan again?

 

[Alfonso Gomez]

1- The space between the radiator and the A/C condenser in front of it can accumulate about a ton of leaves, paper, plastic shopping bags, and other crap. Start by cleaning up this space. Watch out: radiator fins are sharp.
2- After removing that crap, use degreaser and a hose to clean the radiator fins. Crud builds up there.
3- Make sure the radiator is not clogged and you have no leaks.
4- A 160 degrees thermostat helps together with programming the computer to start the fans at a lower temperature.
5- If reprogramming the computer is out of the question, try a manual fan switch from Mid America designs. It enables you to start one or both fans at will. Do not rely on starting the fans by switching on the A/C because maybe you do not want the additional load in the engine or any other reason.
6- A 50/50 mix of Prestone coolant and 12 ounces of Red Line Water Wetter works fine.

If you do all this, you will run cooler. Your temps are way too high for my taste. A very hot engine loses horsepower and can be damaged expensively.
Number 1 above should be done every 3-4 months depending if you drive on dirty roads.
Also, many people do not pay attention to the front spoiler under you front bumper. If it is missing or bent out of shape it may not direct the airflow where it should.
Good luck.

 

[CLABORN1960]

Both fans run when I turn on the A/C....... I will clean out the crud from the places you all have mentioned..... after the radiator is flushed I will use a mixture of 60% water and 40% antifreeze.... I will let you all know something next week...... At what temp is the second fan suppose to kick on with a basic stock set-up?

 

[Vettelt193]

1 fan should be enough to keep the car cool with the A/C off... (i know this because i had a broken fan) I don't know the exact temp the second fan comes on, but it is way up there... I think you mainly need to clean things... see what happens after that.

 

[CLABORN1960]

Okay...... I will spend the next few days cleaning and report back..... thanks for the info....so much info.........

peace

 

[CLABORN1960]

FYI. I was able to shine a flashlight into the access area on the passenger side and look at the front of the radiator. About 1/4 maybe a little more of the front surface of the radiator is covered with some black looking gook, not to mention some pine needles and other assorted stuff stuck to it. So I will definitely spend this weekend removing and cleaning.

One question. When I refill the radiator how do I get all the air out of the system?

 

[CLABORN1960]

update

I was NOT able to get the radiator out. On my 93 the upper shroud has 6 7mm bolts that are located in the lower front part of the shroud. I could not get to those bolts...... Soooo plan B was to hose out what debris I could by sticking the hose into the access vent on the passenger's side. Luckily I was able to get the surface debris out.

I let some of the coolant out, replaced it with distilled water and the temps flucuated like normal. (the fan kicks on at 228 while idling in traffic) Overall the coolant temps were about 15 to 20 degrees lower than last week.

The other problem still exists. After the temp gets to 228 or so it still stumbles some.... this happens with the A/C on or off..... someone said it may be the optispark..... is that the general consensus?