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Is this a blown head gasket give me your opinion

topless82vette

Well-known member
Joined
Nov 1, 2001
Messages
910
Location
southern california
Corvette
1982 convertible (not factory) stock 350cfi auto
I bought this 1990 vette which the seller a young kid claimed thats what it had.

I ran the car on a cold rainy day and yes there was alot of white smoke (keep in mind this car has no cats) but today was sunny and considerably warmer car went to about 230 degrees fans running all the time (however that is believed to be a stuck thermostat) but anyways I saw no visible white smoke this time except a little at first startup.

Now when I do start this car I always have to depress the accelerator to get it to cold start and the car has a very strong fuel odor to it (maybe the coolant temp sensor for the ecm) I've been told if this is bad it could cause the fans not to operate as normal either. so I will change that as well.

It looks like the some sort of head work was done on the car at some point due to how clean everything is on that part of the engine. once warm the engine idles at about 800rpm and idles very nice (motor doesn't seem to stumble or shake) real crisp throttle reponse at all times.

Sorry but I have never had a car with a blown head gasket so I'm kind of confused on this car. Is there anything to test for a blown head gasket available? And would I need to completely flush the cooling system prior to doing this?

The kid also stated coolant contaminates the oil which I haven't noticed just looks like normal clean oil but as much as I've run the car I would have thought it would have started to change to a darker color by now. Car has straight water in it now or if the head gaskets are leaking would that be why the oil always seems clean? I would have thought even just plain water would turn it a milky color.

He also claimed a severe battery drain whiich I found to be a dead cell in the battery so I am wondering if his version of blown head gaskets to be a just a car thats overheating because of a bad thermostat and fans not working.

so how can I be 100% positive of the head gaskets not being blown guys?
 
I would pressure test the cooling system and see if the system holds pressure!!Whats the spark plugs look like??You can usually tell by looking at a spark plug and tell if coolant has been getting to it!! Some of the parts stores have testers for rent or lone!:thumb

PS Also,sometimes water won't leak where anti-freeze will!:thumb
 
I haven't pulled the plugs on it at all so couldn't tell you. How prone are these heads to cracking as well? Just trying to figure my most practicle approach to this engine whether it be fixing it or just replacing it.

Can the oil pan be removed with engine still in the car or is there a crossmember under the engine?
 
I haven't pulled the plugs on it at all so couldn't tell you. How prone are these heads to cracking as well? Just trying to figure my most practicle approach to this engine whether it be fixing it or just replacing it.

Can the oil pan be removed with engine still in the car or is there a crossmember under the engine?

I've never encountered a cracked head on a L98,that don't mean it don't happen!I have ran on to a blown head gasket,but not really that often!!
Just depends on how hot it's been!:thumb:thumb:thumb
 
I would pressure test the cooling system and see if the system holds pressure!!Whats the spark plugs look like??You can usually tell by looking at a spark plug and tell if coolant has been getting to it!! Some of the parts stores have testers for rent or lone!:thumb

PS Also,sometimes water won't leak where anti-freeze will!:thumb

How about a good old fashion compression test?
 
Hi, do a compression test. Doen't sound like a head gasket to me. See what the others say. Roger.
 
Also...

Take off the oil filler cap and look around as much as you can. Use a light to look left and right. Look at the springs, and any left over oil that had not dropped into the oil pan since you last started the car. If you see anything white/frothy looking (like on top of a cappuccino) it means you could have a head gasket problem.
Hope this helps!
 
Look in the oil filler hole for any frothy white substance. It will be mixed in with your oil from the last time you ran your engine!

Hope this helps!
 
I've probably idled the engine maybe a total of a hour and half- to two hours since I bought this thing and the oil has remained the same color. I will however pull the valve covers maybe this weekend and take a look.

Do these L-98's use NON re-useable head bolts ??????
 
I would A) Find someone with a cooling system pressure tester and attach it where the coolant cap is, start the engine (warm) and at 1500-2000 rpms see how much and how quickly it builds pressure on it's own (it's normal for it to build some pressure on it's own while running 12-18 psi range depending on the system) if the pressure rises quickly and pegs the needle then you likely have compression being forced into the cooling system. B) Some automotive tool suppliers Snapon ,Mac,Matco have a "kit" which sucks some coolant into a tube, mixes it with a chemical which will change color if it detects exhaust gases ( CO ) ie blown head gasket,cracked head or block.

I would only use the above methods after I knew I had a coolant loss and it wasn't external OR had already checked for coolant in the oil AND had already checked for coolant on the spark plugs. On a cold start up coolant in the cylinder will usually cause a missfire which clears up as the engine runs, unless it's a large internal leak in which case you would have constant white smoke and a "sweet" smell out of the exhaust. Most of this was mentioned in the above posts (all good suggestions) Once again I'd only try A or B if I couldn't find anything with the normal checks AND I was still sure I had a problem.

Frankly it doesn't sound like a head gasket problem as was stated above the L98 is not known for head gaskets. Just sounds like a overheating problem-- radiator blocked externally (famous for it) maybe internal radiator stopped up, improper aux fan operation or thermostat. Well that's my long winded 2 cents worth. :thumb
 
Ok .... I pulled the thermostat today at least the intake does have water in it so thats at least a good sign. I am heating water on the stove to see what the thermostat does and will let you know. I also pulled the oil filler cap of the drivers valve cover and see absolutely NO signs of milky colored oil, in fact looks like brand new inside of there almost like the heads have recently been done.

I can also see the casting number which ends in 113 which I think are the correct aluminum heads (correct me if I am wrong)

Now a question

the lower part of the throttle body has a coolant hose going to the bottom of the throttle body if this hose is plugged will it cause a coolant flow issue? this car has a bad heater core which is why its like that.

If the thermostat is bad I am going to replace it and get the system flowing then see if it runs like it should.
 
if you got the thermostat out might as well replace it with a fail safe, if you have orielleys where you live just go and tell them you want a fail safe,if the temp gets over 250 it'll lock open had one save my motor about 3 months ago i think they cost about 9.00 to 12.00 but are worth it
 
okay

At boiling the thermostat opens a little but I would expect it to open much more then it does. I also took a garden hose and when any water is put into the upper radiator hose towards the radiator itself water immediately comes out the thermostat hole in the intake.

I also started the car for like 5 seconds with the thermostat housing of and water immediately started coming out.

so I guess that means my cooling system is filled to capacity and circulating and the thermostat has to be the cause correct?


so with a lack of water signs in the oil and valve cover area ..... and being the heads are so clean inside and the fact the previous owner said the car definately got coolant in the oil what do you all think .... Does this car seem like it has blown heads gaskets? could the steam from idling from the tailpipes since it drastically changes from a rainy day to a nice day just be normal? the car has straight water in the system now so I can't smell the exhaust for coolant smell.

Only smell out the tailpipes is a raw fuel smell and on the warmer days there is just very minimal steam/white smoke but when rev'ed black smoke.
 
"IF' it were me, I'd put in a new thermostat, drain and refill the cooling system, put in a bottle of 'Barrs Leak' and button up the whole thing. Drive it about twenty miles and back home, Let it cool, remove the spark plugs and using a compression guage, do a complete compression test. If any of the cylinders show more than a 12 to 20 pound difference, there is a problem with the heads or rings. But it seems to me, that for whatever reason the person who sold you the car has some odd reasoning as to a bad head gasket. But GMjunkie would know a lot more in detail about engines and head gaskets.;)
 
okay

At boiling the thermostat opens a little but I would expect it to open much more then it does.
If the water was boiling and the thermostat wasn't Wide open,It's Bad!!!:thumb
 
well, I changed thermostat, added that bars leaks stuff. idled motor for about and hour the ran motor at 2,000 rpm for 20 minutes and saw no white smoke out tailpipes. temp gauge stayed about 1/3 of the way up with fans on all the time. if I grounded fans periodically car would run to about 230'ish on gauge but when fans came on rapidly cooled down to about the 1/3 way point in approx. 1 minute
 
If the fan circuits are working correctly,without the AC running!! The 1st fan should kick on at about 228* the second one should come on at about 235* if it heats up that far!!:thumb 1 fan should run all the time the AC is on!!:thumb Sounds like up have it whipped!!:thumb:thumb:thumbNow go cruze that bad boy and see how it dose!!:beer
 

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