[Dyk]

I was driving whit my corvette ( a -87 C4 whit a L98 engine and supercharger) and suddenly it started to run badly, and started to come smoke from the valvecover, and i could smell som gas from it to. I shearched for some problem codes at first there were code 34 and 36 i pulled of the + pole from the battery and resetted the computer now there where no problemcodes i whent for a ride and came back still no codes, the car still runs badly and i lookt in the cooling system and i think there were some bubbles and smelled gas. i hawe lookt up the comp. and it was 6 bars. now my thoughts are that i hawe blown the hedgaskets or pistonrings and on slow run the gar works good but when it start to blow in the air from the supercharger the pressure can escape true the hedgasket or pistonrings...

I would like to know what you all think about this, is there some good way to look this up or?

thanx...

 

[raidmagic]

I would look at the headgaskets first.

 

[muddpile]

I vote head gaskets as well. Piston rings shouldn't let a gas smell into the coolant.

 

[Dyk]

yes but its strange that the car runs good when the comp. dosent load anything but when it starts tom load rhe car runs badly. but mayby the hedgasket can resist the normal engine presure but when it starts to load it dosent hold, the comp is blowing whit 12 psi so

 

[Dyk]

Just a little update

Now i hawe pulled some tarts of the engine and i tryed to put air in the cylinders and se if anything leaks out (holding against the engine so it wont turn) i fixed the valves so that they both are closed (the best way i could) bow when i started to put air in the engine it just leakt out :WTF maybe i did not hawe the valves closed properly but still, when i put air in to the cylinders i felt i think (it was a so week flow) that air started to come up from the oilchanels and it did that on all cylinders :WTF it dosent sound right that all the pistonrings should be bad, but maybe i hawe blown the headgasket on all the cylinders i dont know, its strange. when i notised that the car started to run badly i notised that my olipressure was down to 0 but on the oilstick it was on the lower level (why did i not check it :bang ), maybe a bearing has gone bad and later after i filled oil the engine started to sound strange to not a ticking sound and not a ratteling sound but something in the middle

I had the car to a garage snd they did a leakdown test and the results were somewhere around 20-24% on all exept for the num. 7 cyilinder that had 42% the mechanik told me that this is somewhat ok but i dont know.

I hope to get some suggestions on what to do before a take more of the engine. maybe its the headgasket or the pistonrings still i dont know or

 

[Barney 5]

I'd try to get a chemical test on the cooling system that will detect any exhaust in the cooling system. Any shop worth its salt should be able to do this in short order.

 

[grumpyvette]

"
I had the car to a garage snd they did a leakdown test and the results were somewhere around 20-24% on all exept for the num. 7 cyilinder that had 42% the mechanik told me that this is somewhat ok but i dont know.":WTF

THAT LEAK DOWN TEST RESULT IS REALLY (BAD) you should be between 5% and 10% at max with anything over about 15% and you need a refresh/rebuild on rings , cylinder hone and valves(bearings and gaskets also)
Id bet the pistons have detonation damage TIME TO PULL IT DOWN,INSPECT AND REBUILD.......MAYBE TIME TO UPGRADE SOME PARTS WHILE YOUR IN THE PROCESS...............24%-42% WOW!!!HELL ID HAVE IT ALL APART and INSPECTED ,WELL BEFORE IT REACHED 15%

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[Barney 5]

Cylinder #7 should have actually had a miss with 42% leak down. The rest are on the excessive side. I agree that it sounds like it's time for surgery what with all the noises and such you describe.