kbuhagiar

Hello Folks,

My wife and I just purchased a 1992 LT1 coupe with a 6-speed transmission. We got it from the second owner with only 75,000 miles on it. It is in excellent (1-) condition and has been garaged and well-maintained all of its life. Other than a very slight oil leak (1 drop on the driveway every time we park it) I am not aware of any problems with the car. I must say that I am amazed at how much car we got for the price, and although it is 23 years old, it is still a 'new' Corvette to us (we sold our last one, a 1963 Roadster, in 2010).

I am trying to familiarize myself with the C4s in general, and 1992s in particular, and as part of that was hoping to get some input from the other members of C4 nation...are there any quirks or characteristics I should be aware of, or potential areas of concern to watch for (such as the problematic Bose stereo, which was replaced by the PO)? Any mechanical issues that may be looming on the horizon?

Thanks in advance for any assistance and support!

Lloyd Smale

im sure if you read this fourm at all you've come across stuff about the opti spark distributor. Its kind of the Achilles heal of this generation of corvettes. But then honestly theres something major wrong with about any generation.

VikingTrad3r

hi Kbuh. welcome. yah opti for the Lt1.

yes is t it amazballs how much car can be bought in the c4 right now.

welcome to the forum. this forum is better than any magazine will ever be so just visit the general and tech sections iften and you will see what others are fixing and that gives you the mental database of what the quirks and quarks are for your gen of c4.

So far (I am an L98 owner) there isnt a "weak spot" other than just a general lack of keeping up with maintainence. In the 92 year perhaps they have not fallen so far behind. my 85 was atteocious. Its almost caught up now.

for fun you can get yourself a new looking window build sticker for your new car here: https://corvetteparts.com/page/sticker

its not an exact replica, but close!

FASTAZU

Congrats on the C4.. The most common area for oil leaks on an LT1 are at the front or rear of the intake manifold. A very easy and straight forward fix.

When changing fluids be sure to change the fluid in the clutch master cylinder under the ECM.

Do a search on the subject many good write ups on it.

92ragtop

Congrats on the 92!

Consider replacing the Multec injectors with Bosch III from FIC. Apparently, ethanol is not kind to the Multecs. Very easy job on the LT1. Just pull the covers straight off to get at them.

Inspect the area between the rad and the condenser for trash and road debris.

Enjoy!

Christi@n

Congrats for yoy purchase

Pay attention to any operation with fluids around optispark in order to avoid it from wet

These could be:

No wash engine with water in that area
No spill coolant on it if you are going to remove throttle body
No spill coolant on it if you are going to replace thermostat or water pump

And any other fluids operation


As far as oil leak, i've noticed on mine 1995 filling engine oil with 4.5 ~ 4.7 qt instead using 5 qt, car isn't going to leak oil from crank front seal

John A. Marker

with the OPTI...do not wash the engine!!!

The hoses all have a printed date on them. Suggest you check the dates and consider changing all the hoses. Rockauto.com has good prices on these.

All fluids should be changed and or checked.

kbuhagiar

Hello again C4 Nation,

Thanks for all of the responses so far - great information.

We took the Corvette for it first long ride (140 miles) yesterday, and it performed flawlessly. I am just blown away by the gas mileage (slightly above 30 mpg on the open road).

I had a better chance to investigate the oil leak, and based on observations and the occasional whiff of burning oil (on the exhaust manifold), I am confident that it is coming from the upper end and can be easily remedied (fingers crossed!).

One other observation - after the long drive I experienced the (apparently) well-known ZF6 tranny rattle at idle. It only seems to occur after the driveline is warmed up, it goes away when I depress the clutch pedal, and is non-existant when driving. It does not seem to otherwise affect the driveability in any way. How common is this, and should I just ignore it?

Thanks again in advance!

c4cruiser

Welcome to the C4 club

If the car was properly maintained by the previous owner, you should get years of fun from it. I had a '92 convertible for over 7 years and never had one bit of trouble with that car. I drove it from WA to Bowling Green for the 50th Anniversary celebration and the gas mileage averaged 29 MPG for the 6600 miles round trip. And that included a fair amount of triple-digit "cruising"

The '92 was the first year for Mobil-1 full synthetic oil in a 5W-30 viscosity so keep using it although there re some good oils that meet the new Dexos-1 standard. It can't hurt to change all of the fluids if you didn't get service records with the car.

One thing I did twice a year was to spread a very thin coat of dielectric grease on the weatherstripping. That will help to keep it from drying out and will also stop any squeaking noises.

As mentioned, don't use a stream of water to clean the engine. That can easily kill the OptiSpark distributor which is about $450 to replace. I used to use old shop rags and Acetone to wipe off any oil or grease.

My '92 had the Bose Gold system and it worked fine. Some people don't think it's a good system, but with the aftermarket exhaust I had, music quality suffered anyway.

The ZF6 is known for the rattle and it's not a big deal.

Post some pics when you get a chance!!

antfarmer2

congats and welcome to the forum I would do a proper flush by pulling the knock sensors and new hoses. I put in new knocks could not bring myself to put back old parts and they come with the proper dope on them cheap torque is very important. would also put in fresh 02s while your under there.
as far as your trans just drive and enjoy.

kidbubbles

Congrats on the purchase. I have a '93 with 60K miles on it, and I absolutely love it.

I too have the rattle from the ZF6 when the pedal is up. When it's in or running in gear; again, no rattle.

Since I am teaching the wife to drive stick, I envision that I may need to put a clutch in it eventually. Does anyone know if there is a different (clutch, pressure plate, throw-out bearing, etc), that would reduce or eliminate that rattle?

Thanks All

John A. Marker

Do you know if the clutch has been replaced? You will get more rattle out of the transmission if it has. My 95 had very little noise with stock flywheel.

Christi@n

@buhagiar
@c4 cruiser

Dis you get 30-29 mpg on street that was always flat? No riding hill?

I have some difficult to get 30mpg

John A. Marker

I get 28-29 MPG on the freeway between SF Bay area and Seattle...about 1650 miles round trip. Up over the mountains.

DGXR

About these fuel economy numbers people are posting...

Are they from the car's computer "average MPG"? Or are they from real-world calculations (miles driven/gallons added)?

John A. Marker

Mine were based on miles traveled divided by gallons consumed.

c4cruiser

For me, the average I mentioned was based on freeway (autostrada) driving over my entire trip of nearly 6600 miles or 11,000 kilometers. Driving across the US, I crossed mountain passes in the West, flat country through the Midwest and some hills through the South. Outside of some 100+MPH shots, most of the speeds were in the 65-70 MPH (110-130Km/h) range and I used the cruise control as much as possible.

The best average I saw on my trip was going thru Oklahoma and Texas where I saw a computed 31.5 MPG for one tank of gas. As I recall, the speed limits at that time were 60 MPH or 100Km/h

When I drove the car locally, I would see mileage in the 24-26 MPG ranges but that included city driving, back roads and some freeway driving. Never really used the cruise control for local driving.

All of the mileage calculations were done mathematically, the computer MPG display was off by 2-3 MPG (lower)

One thing I did do with the car prior to the trip was to replace the spark plugs and the wires. I made sure the tires were inflated properly too.

I now have a 2002 C5 with a supercharger and it will also deliver gas mileage in the same range as the C4 did. As long as I drive it "conservatively"....

csthews

Welcome to the forum and Congrats on the purchase. I have one more word of caution to add. DO NOT use the steering wheel to help get in and out of the car. A lot of C4's (including mine) have steering wheels with excessive side-to-side play because of this. This can also cause issues with the operation of the dimmer. To repair this will require removing the air bag, so, I choose to live with it.

Enjoy the car, and post up some pics soon.

kbuhagiar

Open road, not always flat, some hills, averaging 65-75 MPH (105-120 KPH), with occasional bursts to 95 MPH (153 KPH) climbing from sea level (San Francisco CA) to 2600 ft at destination (Sonora CA).

Mileage calculations were based on the amount of fuel consumed; traveled 142 miles, consumed 4.7 gallons. Fill-ups at beginning and end of trip.

Doughan

Congrats! I was never a C4 fan until I bought one! I love my C4. Just pulled it out and drove her today. It's an old car and will have some issues but just fix them, and enjoy!