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Hello guys will anyone please help me diagnose my 89 c4 corvette? I recently replaced the water pump and now when i start the car tons of white smoke comes out from both tailpipes and a small amount of smoke is coming from the engine bay near the passenger side header near the oil dip stick. Also when i first put the new water pump on no smoke was coming out and the engine was idling at 6-7 rpm and sounded good,(now which is the next day) it sounds rough and idles at 9-11 rpm and the smoke will not stop so i shut it down until i further investigate the problem.the car has 120000 miles on it. Oil looks a little dark but not milky.I can see some parts of the head gasket sticking out and it looks very old and brittle.Any information would help.

vette196

blown head gasket.....the smoke is from the coolant burning

ddahlgren

Sure sounds like a head gasket failed

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I assumed that as well but i was hoping it can be something else? Can it also possibly be a leaky manifold gasket? There was also dropplets of water coming from the tailpipes but that stopped and smoked continued.Before i replaced the water pump the car overheated bad.Oil temp and coolant temp got really hot over 250.

s carter

you can start by pulling the plugs, when you find a plug that is super clean or wet you are confirmed you have either a very bad intake gasket or a blown head gasket. I vote for the head gasket since you don't have contamination / water in the oil and it got pretty Hot

If you can get your hands on a Radiator pressure tester with plugs out pressurize the system you may hear or have coolant come of bad cylinder

mlm0

My 89 did same thing. Blown head gasket at number 7

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Well i guess all you Vette experts agree its a blown head gasket,im not a fully experienced mechanic but i just replaced the water pump which in my option was easy. Is replacing the head gasket a easy job for a novice mechanic like myself?

s carter

It's a tougher than a water pump, but if you take your time keep track of how things came off if you have a good shop manual you will be OK. You will need some special tool's like a Long 35 torx on a 3/8 drive for making short work of Intake plenum bolts, a regular set of Torx Sockets and a Torque wrench to Torque down heads. The hardest things are the intake and adjusting the valves, and getting the exhaust out of the way each have their challenges.

One thing I will stress is notice the position of the Distributor Rotor mark it remember and don't let the crank move until it is back in to help to confirm TDC when its time to adjust the valves timing the Distributor, some like to bump motor around to TDC on the Balancer/Timing mark before pulling Distributor which is a good way to be sure nothing has moved while doing repairs.

Need A Vette

In my old truck that had a 350, I could do a headgasket in about 1:15, start to finish, but I had built that motor from the ground up, and knew it inside out. Though it wasn't FI, or in a corvette, but in an '81 C10 Pickup. But the principles are the same, just a little more complicated now.

D.

mlm0

I did both head gaskets on my 89. Never did it before, but with help from members on this forum, it started on very first crank. Take lots and lots of pictures, bag and tag everything. Remember some bolts are different lengths, so they need to go back where they came out of. I drew drawings on card board and punched holes in it to hold bolts so t knew where they went. Did a lot of research on gasket thickness and finally just went to Chev dealer and bought parts. Replacement gasket from them was .051. Have your heads rebuilt and surfaced while they are out. I got really confused when it came to adjustment of the lifters, but did it right with forum help and FSM help

remember to get #1 at top dead center before removing parts, makes it easier later

if I can do all by myself, you can. Look up my post on the subject, and it might answer some of your questions

WW7

I'm in the process now of replacing the head gaskets on my 383 motor in my 89 .. I pulled the motor apart yesterday down to the heads , tomorrow the heads come off and go to the machine shop to be checked.. My heads are Dart pro 1 heads and I still had the same number 7 cylinder go out just like the stock motor .. This must be a weak point on all 350 motors... It took me 7 hours to pull the motor apart , it will probably take twice that long to put it back together and I know every bolt on the motor.. I removed all the plugs and spun the motor over, I had coolant blowing out of cylinder 7, that's how I knew it was either a head gasket or something cracked... I'm hoping it's only a head gasket.....WW

viii

I had the same problem on my 85. Not tons of white smoke but enough white smoke. It was my intake manifold gasket. Failed close to the area where the thermostat is located.

ToniJ1960

use a tester that goes into the radiator opening to check for combustion gases in the coolant. rent from autozone or wherever you might have to buy the fluid that goes in the tester.

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Thats encouraging and useful information thanks.Any estimate on the cost to re-do the heads at a machine shop i assume? or is there a known place that specializes in that ?

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Thanks thats what i was thinkinh i already heard like 4 different people that all had that area fail. I pulled the passenger side spark plug thats right behind the oil dipstick and about a quarter ounce of coolant came out. Yes hopefully just a gasket

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Was there any coolant in the oil? Or oil in the coolant? Did coolant come out of any spark plug holes?

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I removed the spark plug behind the oil dipstick and about a quarter ounce of coolant came out ! I then checked the oil and it appears to have coolant mixed in and i looked in the radiator and i can see a few drops of oil in there too! So theres coolant in my oil and a little oil in my coolant.I immediately drained the oil already .Is this a clear indication of a much more serious problem? Not just a cracked manifold or head gasket?

mlm0

I found an engine machine shop out in the country near a small town. Went out and visited with them several times before I decided to use them. Did both heads completely including surfacing for a total of 350.00 not including new head bolts. Only took a week. Found shops in bigger cities much more expensive and would take a lot longer. Good luck

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whats the best way I can tell if the engine block is cracked or if it's just a gasket ? Coolant was already seen on one spark plug and coolant in oil .

WW7

Pulling the heads is the only sure way to tell.. You usually have to have the motor get very hot to crack or warp a head, blocks cracking do happen but not to often...Head gaskets going bad are what happen most of the time...Having.a compression test done on that cylinder will let you know if the problem is in the cylinder or possibly a leaking intake gasket since you do have coolent in your oil...WW

Here's where I'm at now....